--- /dev/null
+* id3v2.3.0
+
+Informal Standard
+Document: id3v2.3
+M. Nilsson
+3rd February 1999
+
+
+1. ID3 tag version 2.3.0
+
+
+1.1. Status of this document
+
+This document is an informal standard and replaces the id3v2.2.0 standard. The
+informal standard is released so that implementors could have a set standard
+before a formal standard is set. The formal standard will use another version
+or revision number if not identical to what is described in this document. The
+contents in this document may change for clarifications but never for added or
+altered functionallity.
+Distribution of this document is unlimited.
+
+1.2. Abstract
+
+This document describes the ID3v2.3.0 standard, which is a more developed
+version of the ID3v2 informal standard (version [:id3v2-00: 2.2.0]), evolved
+from the ID3 tagging system. The ID3v2 offers a flexible way of storing
+information about an audio file within itself to determine its origin and
+contents. The information may be technical information, such as equalisation
+curves, as well as related meta information, such as title, performer,
+copyright etc.
+Contents
+
+ 1. ID3_tag_version_2.3.0
+
+ 1. Status_of_this_document
+ 2. Abstract
+
+ 2. Conventions_in_this_document
+ 3. ID3v2_overview
+
+ 1. ID3v2_header
+ 2. ID3v2_extended_header
+ 3. ID3v2_frame_overview
+
+ 1. Frame_header_flags
+
+ 4. Default_flags
+
+ 4. Declared_ID3v2_frames
+
+ 1. Unique_file_identifier
+ 2. Text_information_frames
+
+ 1. Text_information_frames_-_details
+ 2. User_defined_text_information_frame
+
+ 3. URL_link_frames
+
+ 1. URL_link_frames_-_details
+ 2. User_defined_URL_link_frame
+
+ 4. Involved_people_list
+ 5. Music_CD_identifier
+ 6. Event_timing_codes
+ 7. MPEG_location_lookup_table
+ 8. Synchronised_tempo_codes
+ 9. Unsychronised_lyrics/text_transcription
+ 10. Synchronised_lyrics/text
+ 11. Comments
+ 12. Relative_volume_adjustment
+ 13. Equalisation
+ 14. Reverb
+ 15. Attached_picture
+ 16. General_encapsulated_object
+ 17. Play_counter
+ 18. Popularimeter
+ 19. Recommended_buffer_size
+ 20. Audio_encryption
+ 21. Linked_information
+ 22. Position_synchronisation_frame
+ 23. Terms_of_use_frame
+ 24. Ownership_frame
+ 25. Commercial_frame
+ 26. Encryption_method_registration
+ 27. Group_identification_registration
+ 28. Private_frame
+
+ 5. The_unsynchronisation_scheme
+ 6. Copyright
+ 7. References
+ 8. Appendix
+
+ 1. Appendix_A_-_Genre_List_from_ID3v1
+
+ 9. Author's_Address
+
+
+
+2. Conventions in this document
+
+In the examples, text within "" is a text string exactly as it appears in a
+file. Numbers preceded with $ are hexadecimal and numbers preceded with % are
+binary. $xx is used to indicate a byte with unknown content. %x is used to
+indicate a bit with unknown content. The most significant bit (MSB) of a byte
+is called 'bit 7' and the least significant bit (LSB) is called 'bit 0'.
+A tag is the whole tag described in this document. A frame is a block of
+information in the tag. The tag consists of a header, frames and optional
+padding. A field is a piece of information; one value, a string etc. A numeric
+string is a string that consists of the characters 0-9 only.
+
+
+3. ID3v2 overview
+
+The two biggest design goals were to be able to implement ID3v2 without
+disturbing old software too much and that ID3v2 should be as flexible and
+expandable as possible.
+The first criterion is met by the simple fact that the MPEG decoding software
+uses a syncsignal, embedded in the audiostream, to 'lock on to' the audio.
+Since the ID3v2 tag doesn't contain a valid syncsignal, no software will
+attempt to play the tag. If, for any reason, coincidence make a syncsignal
+appear within the tag it will be taken care of by the 'unsynchronisation
+scheme' described in section_5.
+The second criterion has made a more noticeable impact on the design of the
+ID3v2 tag. It is constructed as a container for several information blocks,
+called frames, whose format need not be known to the software that encounters
+them. At the start of every frame there is an identifier that explains the
+frames' format and content, and a size descriptor that allows software to skip
+unknown frames.
+If a total revision of the ID3v2 tag should be needed, there is a version
+number and a size descriptor in the ID3v2 header.
+The ID3 tag described in this document is mainly targeted at files encoded with
+MPEG-1/2 layer I, MPEG-1/2 layer II, MPEG-1/2 layer III and MPEG-2.5, but may
+work with other types of encoded audio.
+The bitorder in ID3v2 is most significant bit first (MSB). The byteorder in
+multibyte numbers is most significant byte first (e.g. $12345678 would be
+encoded $12 34 56 78).
+It is permitted to include padding after all the final frame (at the end of the
+ID3 tag), making the size of all the frames together smaller than the size
+given in the head of the tag. A possible purpose of this padding is to allow
+for adding a few additional frames or enlarge existing frames within the tag
+without having to rewrite the entire file. The value of the padding bytes must
+be $00.
+
+3.1. ID3v2 header
+
+The ID3v2 tag header, which should be the first information in the file, is 10
+bytes as follows:
+
+ ID3v2/file identifier "ID3"
+ ID3v2 version $03 00
+ ID3v2 flags %abc00000
+ ID3v2 size 4 * %0xxxxxxx
+
+The first three bytes of the tag are always "ID3" to indicate that this is an
+ID3v2 tag, directly followed by the two version bytes. The first byte of ID3v2
+version is it's major version, while the second byte is its revision number. In
+this case this is ID3v2.3.0. All revisions are backwards compatible while major
+versions are not. If software with ID3v2.2.0 and below support should encounter
+version three or higher it should simply ignore the whole tag. Version and
+revision will never be $FF.
+The version is followed by one the ID3v2 flags field, of which currently only
+three flags are used.
+
+
+ a - Unsynchronisation
+ Bit 7 in the 'ID3v2 flags' indicates whether or not unsynchronisation is
+ used (see section_5 for details); a set bit indicates usage.
+
+ b - Extended header
+ The second bit (bit 6) indicates whether or not the header is followed by
+ an extended header. The extended header is described in section_3.2.
+
+ c - Experimental indicator
+ The third bit (bit 5) should be used as an 'experimental indicator'. This
+ flag should always be set when the tag is in an experimental stage.
+
+All the other flags should be cleared. If one of these undefined flags are set
+that might mean that the tag is not readable for a parser that does not know
+the flags function.
+The ID3v2 tag size is encoded with four bytes where the most significant bit
+(bit 7) is set to zero in every byte, making a total of 28 bits. The zeroed
+bits are ignored, so a 257 bytes long tag is represented as $00 00 02 01.
+The ID3v2 tag size is the size of the complete tag after unsychronisation,
+including padding, excluding the header but not excluding the extended header
+(total tag size - 10). Only 28 bits (representing up to 256MB) are used in the
+size description to avoid the introducuction of 'false syncsignals'.
+An ID3v2 tag can be detected with the following pattern:
+
+ $49 44 33 yy yy xx zz zz zz zz
+
+Where yy is less than $FF, xx is the 'flags' byte and zz is less than $80.
+
+3.2. ID3v2 extended header
+
+The extended header contains information that is not vital to the correct
+parsing of the tag information, hence the extended header is optional.
+
+ Extended header size $xx xx xx xx
+ Extended Flags $xx xx
+ Size of padding $xx xx xx xx
+
+Where the 'Extended header size', currently 6 or 10 bytes, excludes itself. The
+'Size of padding' is simply the total tag size excluding the frames and the
+headers, in other words the padding. The extended header is considered separate
+from the header proper, and as such is subject to unsynchronisation.
+The extended flags are a secondary flag set which describes further attributes
+of the tag. These attributes are currently defined as follows
+
+ %x0000000 00000000
+
+
+
+ x - CRC data present
+ If this flag is set four bytes of CRC-32 data is appended to the extended
+ header. The CRC should be calculated before unsynchronisation on the data
+ between the extended header and the padding, i.e. the frames and only the
+ frames.
+
+ Total frame CRC $xx xx xx xx
+
+
+
+3.3. ID3v2 frame overview
+
+As the tag consists of a tag header and a tag body with one or more frames, all
+the frames consists of a frame header followed by one or more fields containing
+the actual information. The layout of the frame header:
+
+ Frame ID $xx xx xx xx (four characters)
+ Size $xx xx xx xx
+ Flags $xx xx
+
+The frame ID made out of the characters capital A-Z and 0-9. Identifiers
+beginning with "X", "Y" and "Z" are for experimental use and free for everyone
+to use, without the need to set the experimental bit in the tag header. Have in
+mind that someone else might have used the same identifier as you. All other
+identifiers are either used or reserved for future use.
+The frame ID is followed by a size descriptor, making a total header size of
+ten bytes in every frame. The size is calculated as frame size excluding frame
+header (frame size - 10).
+In the frame header the size descriptor is followed by two flags bytes. These
+flags are described in section_3.3.1.
+There is no fixed order of the frames' appearance in the tag, although it is
+desired that the frames are arranged in order of significance concerning the
+recognition of the file. An example of such order: UFID, TIT2, MCDI, TRCK ...
+A tag must contain at least one frame. A frame must be at least 1 byte big,
+excluding the header.
+If nothing else is said a string is represented as ISO-8859-1 characters in the
+range $20 - $FF. Such strings are represented as <text string>, or <full text
+string> if newlines are allowed, in the frame descriptions. All Unicode strings
+use 16-bit unicode 2.0 (ISO/IEC 10646-1:1993, UCS-2). Unicode strings must
+begin with the Unicode BOM ($FF FE or $FE FF) to identify the byte order.
+All numeric strings and URLs are always encoded as ISO-8859-1. Terminated
+strings are terminated with $00 if encoded with ISO-8859-1 and $00 00 if
+encoded as unicode. If nothing else is said newline character is forbidden. In
+ISO-8859-1 a new line is represented, when allowed, with $0A only. Frames that
+allow different types of text encoding have a text encoding description byte
+directly after the frame size. If ISO-8859-1 is used this byte should be $00,
+if Unicode is used it should be $01. Strings dependent on encoding is
+represented as <text string according to encoding>, or <full text string
+according to encoding> if newlines are allowed. Any empty Unicode strings which
+are NULL-terminated may have the Unicode BOM followed by a Unicode NULL ($FF FE
+00 00 or $FE FF 00 00).
+The three byte language field is used to describe the language of the frame's
+content, according to ISO-639-2.
+All URLs may be relative, e.g. "picture.png", "../doc.txt".
+If a frame is longer than it should be, e.g. having more fields than specified
+in this document, that indicates that additions to the frame have been made in
+a later version of the ID3v2 standard. This is reflected by the revision number
+in the header of the tag.
+
+3.3.1. Frame header flags
+
+In the frame header the size descriptor is followed by two flags bytes. All
+unused flags must be cleared. The first byte is for 'status messages' and the
+second byte is for encoding purposes. If an unknown flag is set in the first
+byte the frame may not be changed without the bit cleared. If an unknown flag
+is set in the second byte it is likely to not be readable. The flags field is
+defined as follows.
+
+ %abc00000 %ijk00000
+
+
+
+ a - Tag alter preservation
+ This flag tells the software what to do with this frame if it is unknown
+ and the tag is altered in any way. This applies to all kinds of
+ alterations, including adding more padding and reordering the frames.
+
+ 0 Frame should be preserved.
+ 1 Frame should be discarded.
+
+
+ b - File alter preservation
+ This flag tells the software what to do with this frame if it is unknown
+ and the file, excluding the tag, is altered. This does not apply when the
+ audio is completely replaced with other audio data.
+
+ 0 Frame should be preserved.
+ 1 Frame should be discarded.
+
+
+ c - Read only
+ This flag, if set, tells the software that the contents of this frame is
+ intended to be read only. Changing the contents might break something,
+ e.g. a signature. If the contents are changed, without knowledge in why
+ the frame was flagged read only and without taking the proper means to
+ compensate, e.g. recalculating the signature, the bit should be cleared.
+
+ i - Compression
+ This flag indicates whether or not the frame is compressed.
+
+ 0 Frame is not compressed.
+ 1 Frame is compressed using [#ZLIB zlib] with 4 bytes for
+ 'decompressed size' appended to the frame header.
+
+
+ j - Encryption
+ This flag indicates wether or not the frame is enrypted. If set one byte
+ indicating with which method it was encrypted will be appended to the
+ frame header. See section_4.26. for more information about encryption
+ method registration.
+
+ 0 Frame is not encrypted.
+ 1 Frame is encrypted.
+
+
+ k - Grouping identity
+ This flag indicates whether or not this frame belongs in a group with
+ other frames. If set a group identifier byte is added to the frame
+ header. Every frame with the same group identifier belongs to the same
+ group.
+
+ 0 Frame does not contain group information
+ 1 Frame contains group information
+
+
+Some flags indicates that the frame header is extended with additional
+information. This information will be added to the frame header in the same
+order as the flags indicating the additions. I.e. the four bytes of
+decompressed size will preceed the encryption method byte. These additions to
+the frame header, while not included in the frame header size but are included
+in the 'frame size' field, are not subject to encryption or compression.
+
+3.4. Default flags
+
+The default settings for the frames described in this document can be divided
+into the following classes. The flags may be set differently if found more
+suitable by the software.
+
+ 1. Discarded if tag is altered, discarded if file is altered.
+
+ o None.
+
+ 2. Discarded if tag is altered, preserved if file is altered.
+
+ o None.
+
+ 3. Preserved if tag is altered, discarded if file is altered.
+
+ o AENC, ETCO, EQUA, MLLT, POSS, SYLT, SYTC, RVAD, TENC, TLEN, TSIZ
+
+ 4. Preserved if tag is altered, preserved if file is altered.
+
+ o The rest of the frames.
+
+
+
+
+4. Declared ID3v2 frames
+
+The following frames are declared in this draft.
+
+ 4.20 AENC [#sec4.20 Audio encryption]
+ 4.15 APIC [#sec4.15 Attached picture]
+ 4.11 COMM [#sec4.11 Comments]
+ 4.25 COMR [#sec4.25 Commercial frame]
+ 4.26 ENCR [#sec4.26 Encryption method registration]
+ 4.13 EQUA [#sec4.13 Equalization]
+ 4.6 ETCO [#sec4.6 Event timing codes]
+ 4.16 GEOB [#sec4.16 General encapsulated object]
+ 4.27 GRID [#sec4.27 Group identification registration]
+ 4.4 IPLS [#sec4.4 Involved people list]
+ 4.21 LINK [#sec4.21 Linked information]
+ 4.5 MCDI [#sec4.5 Music CD identifier]
+ 4.7 MLLT [#sec4.7 MPEG location lookup table]
+ 4.24 OWNE [#sec4.24 Ownership frame]
+ 4.28 PRIV [#sec4.28 Private frame]
+ 4.17 PCNT [#sec4.17 Play counter]
+ 4.18 POPM [#sec4.18 Popularimeter]
+ 4.22 POSS [#sec4.22 Position synchronisation frame]
+ 4.19 RBUF [#sec4.19 Recommended buffer size]
+ 4.12 RVAD [#sec4.12 Relative volume adjustment]
+ 4.14 RVRB [#sec4.14 Reverb]
+ 4.10 SYLT [#sec4.10 Synchronized lyric/text]
+ 4.8 SYTC [#sec4.8 Synchronized tempo codes]
+ 4.2.1 TALB [#TALB Album/Movie/Show title]
+ 4.2.1 TBPM [#TBPM BPM (beats per minute)]
+ 4.2.1 TCOM [#TCOM Composer]
+ 4.2.1 TCON [#TCON Content type]
+ 4.2.1 TCOP [#TCOP Copyright message]
+ 4.2.1 TDAT [#TDAT Date]
+ 4.2.1 TDLY [#TDLY Playlist delay]
+ 4.2.1 TENC [#TENC Encoded by]
+ 4.2.1 TEXT [#TEXT Lyricist/Text writer]
+ 4.2.1 TFLT [#TFLT File type]
+ 4.2.1 TIME [#TIME Time]
+ 4.2.1 TIT1 [#TIT1 Content group description]
+ 4.2.1 TIT2 [#TIT2 Title/songname/content description]
+ 4.2.1 TIT3 [#TIT3 Subtitle/Description refinement]
+ 4.2.1 TKEY [#TKEY Initial key]
+ 4.2.1 TLAN [#TLAN Language(s)]
+ 4.2.1 TLEN [#TLEN Length]
+ 4.2.1 TMED [#TMED Media type]
+ 4.2.1 TOAL [#TOAL Original album/movie/show title]
+ 4.2.1 TOFN [#TOFN Original filename]
+ 4.2.1 TOLY [#TOLY Original lyricist(s)/text writer(s)]
+ 4.2.1 TOPE [#TOPE Original artist(s)/performer(s)]
+ 4.2.1 TORY [#TORY Original release year]
+ 4.2.1 TOWN [#TOWN File owner/licensee]
+ 4.2.1 TPE1 [#TPE1 Lead performer(s)/Soloist(s)]
+ 4.2.1 TPE2 [#TPE2 Band/orchestra/accompaniment]
+ 4.2.1 TPE3 [#TPE3 Conductor/performer refinement]
+ 4.2.1 TPE4 [#TPE4 Interpreted, remixed, or otherwise modified by]
+ 4.2.1 TPOS [#TPOS Part of a set]
+ 4.2.1 TPUB [#TPUB Publisher]
+ 4.2.1 TRCK [#TRCK Track number/Position in set]
+ 4.2.1 TRDA [#TRDA Recording dates]
+ 4.2.1 TRSN [#TRSN Internet radio station name]
+ 4.2.1 TRSO [#TRSO Internet radio station owner]
+ 4.2.1 TSIZ [#TSIZ Size]
+ 4.2.1 TSRC [#TSRC ISRC (international standard recording code)]
+ 4.2.1 TSSE [#TSEE Software/Hardware and settings used for encoding]
+ 4.2.1 TYER [#TYER Year]
+ 4.2.2 TXXX [#TXXX User defined text information frame]
+ 4.1 UFID [#sec4.1 Unique file identifier]
+ 4.23 USER [#sec4.23 Terms of use]
+ 4.9 USLT [#sec4.9 Unsychronized lyric/text transcription]
+ 4.3.1 WCOM [#WCOM Commercial information]
+ 4.3.1 WCOP [#WCOP Copyright/Legal information]
+ 4.3.1 WOAF [#WOAF Official audio file webpage]
+ 4.3.1 WOAR [#WOAR Official artist/performer webpage]
+ 4.3.1 WOAS [#WOAS Official audio source webpage]
+ 4.3.1 WORS [#WORS Official internet radio station homepage]
+ 4.3.1 WPAY [#WPAY Payment]
+ 4.3.1 WPUB [#WPUB Publishers official webpage]
+ 4.3.2 WXXX [#WXXX User defined URL link frame]
+
+
+4.1. Unique file identifier
+
+This frame's purpose is to be able to identify the audio file in a database
+that may contain more information relevant to the content. Since
+standardisation of such a database is beyond this document, all frames begin
+with a null-terminated string with a URL containing an email address, or a link
+to a location where an email address can be found, that belongs to the
+organisation responsible for this specific database implementation. Questions
+regarding the database should be sent to the indicated email address. The URL
+should not be used for the actual database queries. The string "http://
+www.id3.org/dummy/ufid.html" should be used for tests. Software that isn't told
+otherwise may safely remove such frames. The 'Owner identifier' must be non-
+empty (more than just a termination). The 'Owner identifier' is then followed
+by the actual identifier, which may be up to 64 bytes. There may be more than
+one "UFID" frame in a tag, but only one with the same 'Owner identifier'.
+
+ <Header for 'Unique file identifier', ID: "UFID">
+ Owner identifier <text string> $00
+ Identifier <up to 64 bytes binary data>
+
+
+4.2. Text information frames
+
+The text information frames are the most important frames, containing
+information like artist, album and more. There may only be one text information
+frame of its kind in an tag. If the textstring is followed by a termination
+($00 (00)) all the following information should be ignored and not be
+displayed. All text frame identifiers begin with "T". Only text frame
+identifiers begin with "T", with the exception of the "TXXX" frame. All the
+text information frames have the following format:
+
+ <Header for 'Text information frame', ID: "T000" - "TZZZ", excluding "TXXX"
+ described in 4.2.2.>
+ Text encoding $xx
+ Information <text string according to encoding>
+
+
+4.2.1. Text information frames - details
+
+
+
+ TALB
+ The 'Album/Movie/Show title' frame is intended for the title of the
+ recording(/source of sound) which the audio in the file is taken from.
+
+
+
+ TBPM
+ The 'BPM' frame contains the number of beats per minute in the mainpart
+ of the audio. The BPM is an integer and represented as a numerical
+ string.
+
+
+
+ TCOM
+ The 'Composer(s)' frame is intended for the name of the composer(s). They
+ are seperated with the "/" character.
+
+
+
+ TCON
+ The 'Content type', which previously was stored as a one byte numeric
+ value only, is now a numeric string. You may use one or several of the
+ types as ID3v1.1 did or, since the category list would be impossible to
+ maintain with accurate and up to date categories, define your own.
+
+ References to the ID3v1 genres can be made by, as first byte, enter "("
+ followed by a number from the genres list (appendix A) and ended with a
+ ")" character. This is optionally followed by a refinement, e.g. "(21)"
+ or "(4)Eurodisco". Several references can be made in the same frame, e.g.
+ "(51)(39)". If the refinement should begin with a "(" character it should
+ be replaced with "((", e.g. "((I can figure out any genre)" or "(55)((I
+ think...)". The following new content types is defined in ID3v2 and is
+ implemented in the same way as the numerig content types, e.g. "(RX)".
+
+ RX Remix
+ CR Cover
+
+
+
+
+ TCOP
+ The 'Copyright message' frame, which must begin with a year and a space
+ character (making five characters), is intended for the copyright holder
+ of the original sound, not the audio file itself. The absence of this
+ frame means only that the copyright information is unavailable or has
+ been removed, and must not be interpreted to mean that the sound is
+ public domain. Every time this field is displayed the field must be
+ preceded with "Copyright © ".
+
+
+
+ TDAT
+ The 'Date' frame is a numeric string in the DDMM format containing the
+ date for the recording. This field is always four characters long.
+
+
+
+ TDLY
+ The 'Playlist delay' defines the numbers of milliseconds of silence
+ between every song in a playlist. The player should use the "ETC" frame,
+ if present, to skip initial silence and silence at the end of the audio
+ to match the 'Playlist delay' time. The time is represented as a numeric
+ string.
+
+
+
+ TENC
+ The 'Encoded by' frame contains the name of the person or organisation
+ that encoded the audio file. This field may contain a copyright message,
+ if the audio file also is copyrighted by the encoder.
+
+
+
+ TEXT
+ The 'Lyricist(s)/Text writer(s)' frame is intended for the writer(s) of
+ the text or lyrics in the recording. They are seperated with the "/
+ " character.
+
+
+
+ TFLT
+ The 'File type' frame indicates which type of audio this tag defines. The
+ following type and refinements are defined:
+
+ MPG MPEG Audio
+ /1 MPEG 1/2 layer I
+ /2 MPEG 1/2 layer II
+ /3 MPEG 1/2 layer III
+ /2.5 MPEG 2.5
+ /AAC Advanced audio compression
+ VQF Transform-domain Weighted Interleave Vector Quantization
+ PCM Pulse Code Modulated audio
+
+
+but other types may be used, not for these types though. This is used in a
+similar way to the predefined types in the "TMED" frame, but without
+parentheses. If this frame is not present audio type is assumed to be "MPG".
+
+
+ TIME
+ The 'Time' frame is a numeric string in the HHMM format containing the
+ time for the recording. This field is always four characters long.
+
+
+
+ TIT1
+ The 'Content group description' frame is used if the sound belongs to a
+ larger category of sounds/music. For example, classical music is often
+ sorted in different musical sections (e.g. "Piano Concerto", "Weather -
+ Hurricane").
+
+
+
+ TIT2
+ The 'Title/Songname/Content description' frame is the actual name of the
+ piece (e.g. "Adagio", "Hurricane Donna").
+
+
+
+ TIT3
+ The 'Subtitle/Description refinement' frame is used for information
+ directly related to the contents title (e.g. "Op. 16" or "Performed live
+ at Wembley").
+
+
+
+ TKEY
+ The 'Initial key' frame contains the musical key in which the sound
+ starts. It is represented as a string with a maximum length of three
+ characters. The ground keys are represented with "A","B","C","D","E", "F"
+ and "G" and halfkeys represented with "b" and "#". Minor is represented
+ as "m". Example "Cbm". Off key is represented with an "o" only.
+
+
+
+ TLAN
+ The 'Language(s)' frame should contain the languages of the text or
+ lyrics spoken or sung in the audio. The language is represented with
+ three characters according to ISO-639-2. If more than one language is
+ used in the text their language codes should follow according to their
+ usage.
+
+
+
+ TLEN
+ The 'Length' frame contains the length of the audiofile in milliseconds,
+ represented as a numeric string.
+
+
+
+ TMED
+ The 'Media type' frame describes from which media the sound originated.
+ This may be a text string or a reference to the predefined media types
+ found in the list below. References are made within "(" and ")" and are
+ optionally followed by a text refinement, e.g. "(MC) with four channels".
+ If a text refinement should begin with a "(" character it should be
+ replaced with "((" in the same way as in the "TCO" frame. Predefined
+ refinements is appended after the media type, e.g. "(CD/A)" or "(VID/PAL/
+ VHS)".
+
+ DIG Other digital media
+ /A Analog transfer from media
+
+ ANA Other analog media
+ /WAC Wax cylinder
+ /8CA 8-track tape cassette
+
+ CD CD
+ /A Analog transfer from media
+ /DD DDD
+ /AD ADD
+ /AA AAD
+
+ LD Laserdisc
+ /A Analog transfer from media
+
+ TT Turntable records
+ /33 33.33 rpm
+ /45 45 rpm
+ /71 71.29 rpm
+ /76 76.59 rpm
+ /78 78.26 rpm
+ /80 80 rpm
+
+ MD MiniDisc
+ /A Analog transfer from media
+
+ DAT DAT
+ /A Analog transfer from media
+ /1 standard, 48 kHz/16 bits, linear
+ /2 mode 2, 32 kHz/16 bits, linear
+ /3 mode 3, 32 kHz/12 bits, nonlinear, low speed
+ /4 mode 4, 32 kHz/12 bits, 4 channels
+ /5 mode 5, 44.1 kHz/16 bits, linear
+ /6 mode 6, 44.1 kHz/16 bits, 'wide track' play
+
+ DCC DCC
+ /A Analog transfer from media
+
+ DVD DVD
+ /A Analog transfer from media
+
+ TV Television
+ /PAL PAL
+ /NTSC NTSC
+ /SECAM SECAM
+
+ VID Video
+ /PAL PAL
+ /NTSC NTSC
+ /SECAM SECAM
+ /VHS VHS
+ /SVHS S-VHS
+ /BETA BETAMAX
+
+ RAD Radio
+ /FM FM
+ /AM AM
+ /LW LW
+ /MW MW
+
+ TEL Telephone
+ /I ISDN
+
+ MC MC (normal cassette)
+ /4 4.75 cm/s (normal speed for a two sided cassette)
+ /9 9.5 cm/s
+ /I Type I cassette (ferric/normal)
+ /II Type II cassette (chrome)
+ /III Type III cassette (ferric chrome)
+ /IV Type IV cassette (metal)
+
+ REE Reel
+ /9 9.5 cm/s
+ /19 19 cm/s
+ /38 38 cm/s
+ /76 76 cm/s
+ /I Type I cassette (ferric/normal)
+ /II Type II cassette (chrome)
+ /III Type III cassette (ferric chrome)
+ /IV Type IV cassette (metal)
+
+
+
+
+ TOAL
+ The 'Original album/movie/show title' frame is intended for the title of
+ the original recording (or source of sound), if for example the music in
+ the file should be a cover of a previously released song.
+
+
+
+ TOFN
+ The 'Original filename' frame contains the preferred filename for the
+ file, since some media doesn't allow the desired length of the filename.
+ The filename is case sensitive and includes its suffix.
+
+
+
+ TOLY
+ The 'Original lyricist(s)/text writer(s)' frame is intended for the text
+ writer(s) of the original recording, if for example the music in the file
+ should be a cover of a previously released song. The text writers are
+ seperated with the "/" character.
+
+
+
+ TOPE
+ The 'Original artist(s)/performer(s)' frame is intended for the performer
+ (s) of the original recording, if for example the music in the file
+ should be a cover of a previously released song. The performers are
+ seperated with the "/" character.
+
+
+
+ TORY
+ The 'Original release year' frame is intended for the year when the
+ original recording, if for example the music in the file should be a
+ cover of a previously released song, was released. The field is formatted
+ as in the "TYER" frame.
+
+
+
+ TOWN
+ The 'File owner/licensee' frame contains the name of the owner or
+ licensee of the file and it's contents.
+
+
+
+ TPE1
+ The 'Lead artist(s)/Lead performer(s)/Soloist(s)/Performing group' is
+ used for the main artist(s). They are seperated with the "/" character.
+
+
+
+ TPE2
+ The 'Band/Orchestra/Accompaniment' frame is used for additional
+ information about the performers in the recording.
+
+
+
+ TPE3
+ The 'Conductor' frame is used for the name of the conductor.
+
+
+
+ TPE4
+ The 'Interpreted, remixed, or otherwise modified by' frame contains more
+ information about the people behind a remix and similar interpretations
+ of another existing piece.
+
+
+
+ TPOS
+ The 'Part of a set' frame is a numeric string that describes which part
+ of a set the audio came from. This frame is used if the source described
+ in the "TALB" frame is divided into several mediums, e.g. a double CD.
+ The value may be extended with a "/" character and a numeric string
+ containing the total number of parts in the set. E.g. "1/2".
+
+
+
+ TPUB
+ The 'Publisher' frame simply contains the name of the label or publisher.
+
+
+
+ TRCK
+ The 'Track number/Position in set' frame is a numeric string containing
+ the order number of the audio-file on its original recording. This may be
+ extended with a "/" character and a numeric string containing the total
+ numer of tracks/elements on the original recording. E.g. "4/9".
+
+
+
+ TRDA
+ The 'Recording dates' frame is a intended to be used as complement to the
+ "TYER", "TDAT" and "TIME" frames. E.g. "4th-7th June, 12th June" in
+ combination with the "TYER" frame.
+
+
+
+ TRSN
+ The 'Internet radio station name' frame contains the name of the internet
+ radio station from which the audio is streamed.
+
+
+
+ TRSO
+ The 'Internet radio station owner' frame contains the name of the owner
+ of the internet radio station from which the audio is streamed.
+
+
+
+ TSIZ
+ The 'Size' frame contains the size of the audiofile in bytes, excluding
+ the ID3v2 tag, represented as a numeric string.
+
+
+
+ TSRC
+ The 'ISRC' frame should contain the International Standard Recording Code
+ (ISRC) (12 characters).
+
+
+
+ TSSE
+ The 'Software/Hardware and settings used for encoding' frame includes the
+ used audio encoder and its settings when the file was encoded. Hardware
+ refers to hardware encoders, not the computer on which a program was run.
+
+
+
+ TYER
+ The 'Year' frame is a numeric string with a year of the recording. This
+ frames is always four characters long (until the year 10000).
+
+
+4.2.2. User defined text information frame
+
+This frame is intended for one-string text information concerning the audiofile
+in a similar way to the other "T"-frames. The frame body consists of a
+description of the string, represented as a terminated string, followed by the
+actual string. There may be more than one "TXXX" frame in each tag, but only
+one with the same description.
+
+ <Header for 'User defined text information frame', ID: "TXXX">
+ Text encoding $xx
+ Description <text string according to encoding> $00 (00)
+ Value <text string according to encoding>
+
+
+4.3. URL link frames
+
+With these frames dynamic data such as webpages with touring information, price
+information or plain ordinary news can be added to the tag. There may only be
+one URL link frame of its kind in an tag, except when stated otherwise in the
+frame description. If the textstring is followed by a termination ($00 (00))
+all the following information should be ignored and not be displayed. All URL
+link frame identifiers begins with "W". Only URL link frame identifiers begins
+with "W". All URL link frames have the following format:
+
+ <Header for 'URL link frame', ID: "W000" - "WZZZ", excluding "WXXX" described
+ in 4.3.2.>
+ URL <text string>
+
+
+4.3.1. URL link frames - details
+
+
+
+ WCOM
+ The 'Commercial information' frame is a URL pointing at a webpage with
+ information such as where the album can be bought. There may be more than
+ one "WCOM" frame in a tag, but not with the same content.
+
+
+
+ WCOP
+ The 'Copyright/Legal information' frame is a URL pointing at a webpage
+ where the terms of use and ownership of the file is described.
+
+
+
+ WOAF
+ The 'Official audio file webpage' frame is a URL pointing at a file
+ specific webpage.
+
+
+
+ WOAR
+ The 'Official artist/performer webpage' frame is a URL pointing at the
+ artists official webpage. There may be more than one "WOAR" frame in a
+ tag if the audio contains more than one performer, but not with the same
+ content.
+
+
+
+ WOAS
+ The 'Official audio source webpage' frame is a URL pointing at the
+ official webpage for the source of the audio file, e.g. a movie.
+
+
+
+ WORS
+ The 'Official internet radio station homepage' contains a URL pointing at
+ the homepage of the internet radio station.
+
+
+
+ WPAY
+ The 'Payment' frame is a URL pointing at a webpage that will handle the
+ process of paying for this file.
+
+
+
+ WPUB
+ The 'Publishers official webpage' frame is a URL pointing at the official
+ wepage for the publisher.
+
+
+4.3.2. User defined URL link frame
+
+This frame is intended for URL links concerning the audiofile in a similar way
+to the other "W"-frames. The frame body consists of a description of the
+string, represented as a terminated string, followed by the actual URL. The URL
+is always encoded with ISO-8859-1. There may be more than one "WXXX" frame in
+each tag, but only one with the same description.
+
+ <Header for 'User defined URL link frame', ID: "WXXX">
+ Text encoding $xx
+ Description <text string according to encoding> $00 (00)
+ URL <text string>
+
+
+4.4. Involved people list
+
+Since there might be a lot of people contributing to an audio file in various
+ways, such as musicians and technicians, the 'Text information frames' are
+often insufficient to list everyone involved in a project. The 'Involved people
+list' is a frame containing the names of those involved, and how they were
+involved. The body simply contains a terminated string with the involvement
+directly followed by a terminated string with the involvee followed by a new
+involvement and so on. There may only be one "IPLS" frame in each tag.
+
+ <Header for 'Involved people list', ID: "IPLS">
+ Text encoding $xx
+ People list strings <text strings according to encoding>
+
+
+4.5. Music CD identifier
+
+This frame is intended for music that comes from a CD, so that the CD can be
+identified in databases such as the CDDB. The frame consists of a binary dump
+of the Table Of Contents, TOC, from the CD, which is a header of 4 bytes and
+then 8 bytes/track on the CD plus 8 bytes for the 'lead out' making a maximum
+of 804 bytes. The offset to the beginning of every track on the CD should be
+described with a four bytes absolute CD-frame address per track, and not with
+absolute time. This frame requires a present and valid "TRCK" frame, even if
+the CD's only got one track. There may only be one "MCDI" frame in each tag.
+
+ <Header for 'Music CD identifier', ID: "MCDI">
+ CD TOC <binary data>
+
+
+4.6. Event timing codes
+
+This frame allows synchronisation with key events in a song or sound. The
+header is:
+
+ <Header for 'Event timing codes', ID: "ETCO">
+ Time stamp format $xx
+
+Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+Abolute time means that every stamp contains the time from the beginning of the
+file.
+Followed by a list of key events in the following format:
+
+ Type of event $xx
+ Time stamp $xx (xx ...)
+
+The 'Time stamp' is set to zero if directly at the beginning of the sound or
+after the previous event. All events should be sorted in chronological order.
+The type of event is as follows:
+
+ $00 padding (has no meaning)
+ $01 end of initial silence
+ $02 intro start
+ $03 mainpart start
+ $04 outro start
+ $05 outro end
+ $06 verse start
+ $07 refrain start
+ $08 interlude start
+ $09 theme start
+ $0A variation start
+ $0B key change
+ $0C time change
+ $0D momentary unwanted noise (Snap, Crackle & Pop)
+ $0E sustained noise
+ $0F sustained noise end
+ $10 intro end
+ $11 mainpart end
+ $12 verse end
+ $13 refrain end
+ $14 theme end
+ $15-$DF reserved for future use
+ $E0-$EF not predefined sync 0-F
+ $F0-$FC reserved for future use
+ $FD audio end (start of silence)
+ $FE audio file ends
+ $FF one more byte of events follows (all the following bytes with the
+ value $FF have the same function)
+
+Terminating the start events such as "intro start" is not required. The 'Not
+predefined sync's ($E0-EF) are for user events. You might want to synchronise
+your music to something, like setting of an explosion on-stage, turning on your
+screensaver etc.
+There may only be one "ETCO" frame in each tag.
+
+4.7. MPEG location lookup table
+
+To increase performance and accuracy of jumps within a MPEG audio file, frames
+with timecodes in different locations in the file might be useful. The ID3v2
+frame includes references that the software can use to calculate positions in
+the file. After the frame header is a descriptor of how much the 'frame
+counter' should increase for every reference. If this value is two then the
+first reference points out the second frame, the 2nd reference the 4th frame,
+the 3rd reference the 6th frame etc. In a similar way the 'bytes between
+reference' and 'milliseconds between reference' points out bytes and
+milliseconds respectively.
+Each reference consists of two parts; a certain number of bits, as defined in
+'bits for bytes deviation', that describes the difference between what is said
+in 'bytes between reference' and the reality and a certain number of bits, as
+defined in 'bits for milliseconds deviation', that describes the difference
+between what is said in 'milliseconds between reference' and the reality. The
+number of bits in every reference, i.e. 'bits for bytes deviation'+'bits for
+milliseconds deviation', must be a multiple of four. There may only be one
+"MLLT" frame in each tag.
+
+ <Header for 'Location lookup table', ID: "MLLT">
+ MPEG frames between reference $xx xx
+ Bytes between reference $xx xx xx
+ Milliseconds between reference $xx xx xx
+ Bits for bytes deviation $xx
+ Bits for milliseconds dev. $xx
+
+Then for every reference the following data is included;
+
+ Deviation in bytes %xxx....
+ Deviation in milliseconds %xxx....
+
+
+4.8. Synchronised tempo codes
+
+For a more accurate description of the tempo of a musical piece this frame
+might be used. After the header follows one byte describing which time stamp
+format should be used. Then follows one or more tempo codes. Each tempo code
+consists of one tempo part and one time part. The tempo is in BPM described
+with one or two bytes. If the first byte has the value $FF, one more byte
+follows, which is added to the first giving a range from 2 - 510 BPM, since $00
+and $01 is reserved. $00 is used to describe a beat-free time period, which is
+not the same as a music-free time period. $01 is used to indicate one single
+beat-stroke followed by a beat-free period.
+The tempo descriptor is followed by a time stamp. Every time the tempo in the
+music changes, a tempo descriptor may indicate this for the player. All tempo
+descriptors should be sorted in chronological order. The first beat-stroke in a
+time-period is at the same time as the beat description occurs. There may only
+be one "SYTC" frame in each tag.
+
+ <Header for 'Synchronised tempo codes', ID: "SYTC">
+ Time stamp format $xx
+ Tempo data <binary data>
+
+Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+Abolute time means that every stamp contains the time from the beginning of the
+file.
+
+4.9. Unsychronised lyrics/text transcription
+
+This frame contains the lyrics of the song or a text transcription of other
+vocal activities. The head includes an encoding descriptor and a content
+descriptor. The body consists of the actual text. The 'Content descriptor' is a
+terminated string. If no descriptor is entered, 'Content descriptor' is $00
+(00) only. Newline characters are allowed in the text. There may be more than
+one 'Unsynchronised lyrics/text transcription' frame in each tag, but only one
+with the same language and content descriptor.
+
+ <Header for 'Unsynchronised lyrics/text transcription', ID: "USLT">
+ Text encoding $xx
+ Language $xx xx xx
+ Content descriptor <text string according to encoding> $00 (00)
+ Lyrics/text <full text string according to encoding>
+
+
+4.10. Synchronised lyrics/text
+
+This is another way of incorporating the words, said or sung lyrics, in the
+audio file as text, this time, however, in sync with the audio. It might also
+be used to describing events e.g. occurring on a stage or on the screen in sync
+with the audio. The header includes a content descriptor, represented with as
+terminated textstring. If no descriptor is entered, 'Content descriptor' is $00
+(00) only.
+
+ <Header for 'Synchronised lyrics/text', ID: "SYLT">
+ Text encoding $xx
+ Language $xx xx xx
+ Time stamp format $xx
+ Content type $xx
+ Content descriptor <text string according to encoding> $00 (00)
+
+Encoding:
+
+ $00 ISO-8859-1 character set is used => $00 is sync identifier.
+ $01 Unicode character set is used => $00 00 is sync identifier.
+
+Content type:
+
+ $00 is other
+ $01 is lyrics
+ $02 is text transcription
+ $03 is movement/part name (e.g. "Adagio")
+ $04 is events (e.g. "Don Quijote enters the stage")
+ $05 is chord (e.g. "Bb F Fsus")
+ $06 is trivia/'pop up' information
+
+Time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+Abolute time means that every stamp contains the time from the beginning of the
+file.
+The text that follows the frame header differs from that of the unsynchronised
+lyrics/text transcription in one major way. Each syllable (or whatever size of
+text is considered to be convenient by the encoder) is a null terminated string
+followed by a time stamp denoting where in the sound file it belongs. Each sync
+thus has the following structure:
+
+ Terminated text to be synced (typically a syllable)
+ Sync identifier (terminator to above string) $00 (00)
+ Time stamp $xx (xx ...)
+
+The 'time stamp' is set to zero or the whole sync is omitted if located
+directly at the beginning of the sound. All time stamps should be sorted in
+chronological order. The sync can be considered as a validator of the
+subsequent string.
+Newline ($0A) characters are allowed in all "SYLT" frames and should be used
+after every entry (name, event etc.) in a frame with the content type $03 -
+$04.
+A few considerations regarding whitespace characters: Whitespace separating
+words should mark the beginning of a new word, thus occurring in front of the
+first syllable of a new word. This is also valid for new line characters. A
+syllable followed by a comma should not be broken apart with a sync (both the
+syllable and the comma should be before the sync).
+An example: The "USLT" passage
+
+ "Strangers in the night" $0A "Exchanging glances"
+
+would be "SYLT" encoded as:
+
+ "Strang" $00 xx xx "ers" $00 xx xx " in" $00 xx xx " the" $00
+ xx xx " night" $00 xx xx 0A "Ex" $00 xx xx "chang" $00 xx xx
+ "ing" $00 xx xx "glan" $00 xx xx "ces" $00 xx xx
+
+There may be more than one "SYLT" frame in each tag, but only one with the same
+language and content descriptor.
+
+4.11. Comments
+
+This frame is indended for any kind of full text information that does not fit
+in any other frame. It consists of a frame header followed by encoding,
+language and content descriptors and is ended with the actual comment as a text
+string. Newline characters are allowed in the comment text string. There may be
+more than one comment frame in each tag, but only one with the same language
+and content descriptor.
+
+ <Header for 'Comment', ID: "COMM">
+ Text encoding $xx
+ Language $xx xx xx
+ Short content descrip. <text string according to encoding> $00 (00)
+ The actual text <full text string according to encoding>
+
+
+4.12. Relative volume adjustment
+
+This is a more subjective function than the previous ones. It allows the user
+to say how much he wants to increase/decrease the volume on each channel while
+the file is played. The purpose is to be able to align all files to a reference
+volume, so that you don't have to change the volume constantly. This frame may
+also be used to balance adjust the audio. If the volume peak levels are known
+then this could be described with the 'Peak volume right' and 'Peak volume
+left' field. If Peakvolume is not known these fields could be left zeroed or,
+if no other data follows, be completely omitted. There may only be one "RVAD"
+frame in each tag.
+
+ <Header for 'Relative volume adjustment', ID: "RVAD">
+ Increment/decrement %00xxxxxx
+ Bits used for volume descr. $xx
+ Relative volume change, right $xx xx (xx ...)
+ Relative volume change, left $xx xx (xx ...)
+ Peak volume right $xx xx (xx ...)
+ Peak volume left $xx xx (xx ...)
+
+In the increment/decrement field bit 0 is used to indicate the right channel
+and bit 1 is used to indicate the left channel. 1 is increment and 0 is
+decrement.
+The 'bits used for volume description' field is normally $10 (16 bits) for MPEG
+2 layer I, II and III and MPEG 2.5. This value may not be $00. The volume is
+always represented with whole bytes, padded in the beginning (highest bits)
+when 'bits used for volume description' is not a multiple of eight.
+This datablock is then optionally followed by a volume definition for the left
+and right back channels. If this information is appended to the frame the first
+two channels will be treated as front channels. In the increment/decrement
+field bit 2 is used to indicate the right back channel and bit 3 for the left
+back channel.
+
+ Relative volume change, right back $xx xx (xx ...)
+ Relative volume change, left back $xx xx (xx ...)
+ Peak volume right back $xx xx (xx ...)
+ Peak volume left back $xx xx (xx ...)
+
+If the center channel adjustment is present the following is appended to the
+existing frame, after the left and right back channels. The center channel is
+represented by bit 4 in the increase/decrease field.
+
+ Relative volume change, center $xx xx (xx ...)
+ Peak volume center $xx xx (xx ...)
+
+If the bass channel adjustment is present the following is appended to the
+existing frame, after the center channel. The bass channel is represented by
+bit 5 in the increase/decrease field.
+
+ Relative volume change, bass $xx xx (xx ...)
+ Peak volume bass $xx xx (xx ...)
+
+
+4.13. Equalisation
+
+This is another subjective, alignment frame. It allows the user to predefine an
+equalisation curve within the audio file. There may only be one "EQUA" frame in
+each tag.
+
+ <Header of 'Equalisation', ID: "EQUA">
+ Adjustment bits $xx
+
+The 'adjustment bits' field defines the number of bits used for representation
+of the adjustment. This is normally $10 (16 bits) for MPEG 2 layer I, II and
+III and MPEG 2.5. This value may not be $00.
+This is followed by 2 bytes + ('adjustment bits' rounded up to the nearest
+byte) for every equalisation band in the following format, giving a frequency
+range of 0 - 32767Hz:
+
+ Increment/decrement %x (MSB of the Frequency)
+ Frequency (lower 15 bits)
+ Adjustment $xx (xx ...)
+
+The increment/decrement bit is 1 for increment and 0 for decrement. The
+equalisation bands should be ordered increasingly with reference to frequency.
+All frequencies don't have to be declared. The equalisation curve in the
+reading software should be interpolated between the values in this frame. Three
+equal adjustments for three subsequent frequencies. A frequency should only be
+described once in the frame.
+
+4.14. Reverb
+
+Yet another subjective one. You may here adjust echoes of different kinds.
+Reverb left/right is the delay between every bounce in ms. Reverb bounces left/
+right is the number of bounces that should be made. $FF equals an infinite
+number of bounces. Feedback is the amount of volume that should be returned to
+the next echo bounce. $00 is 0%, $FF is 100%. If this value were $7F, there
+would be 50% volume reduction on the first bounce, 50% of that on the second
+and so on. Left to left means the sound from the left bounce to be played in
+the left speaker, while left to right means sound from the left bounce to be
+played in the right speaker.
+'Premix left to right' is the amount of left sound to be mixed in the right
+before any reverb is applied, where $00 id 0% and $FF is 100%. 'Premix right to
+left' does the same thing, but right to left. Setting both premix to $FF would
+result in a mono output (if the reverb is applied symmetric). There may only be
+one "RVRB" frame in each tag.
+
+ <Header for 'Reverb', ID: "RVRB">
+ Reverb left (ms) $xx xx
+ Reverb right (ms) $xx xx
+ Reverb bounces, left $xx
+ Reverb bounces, right $xx
+ Reverb feedback, left to left $xx
+ Reverb feedback, left to right $xx
+ Reverb feedback, right to right $xx
+ Reverb feedback, right to left $xx
+ Premix left to right $xx
+ Premix right to left $xx
+
+
+4.15. Attached picture
+
+This frame contains a picture directly related to the audio file. Image format
+is the MIME type and subtype for the image. In the event that the MIME media
+type name is omitted, "image/" will be implied. The "image/png" or "image/jpeg"
+picture format should be used when interoperability is wanted. Description is a
+short description of the picture, represented as a terminated textstring. The
+description has a maximum length of 64 characters, but may be empty. There may
+be several pictures attached to one file, each in their individual "APIC"
+frame, but only one with the same content descriptor. There may only be one
+picture with the picture type declared as picture type $01 and $02
+respectively. There is the possibility to put only a link to the image file by
+using the 'MIME type' "-->" and having a complete URL instead of picture data.
+The use of linked files should however be used sparingly since there is the
+risk of separation of files.
+
+ <Header for 'Attached picture', ID: "APIC">
+ Text encoding $xx
+ MIME type <text string> $00
+ Picture type $xx
+ Description <text string according to encoding> $00 (00)
+ Picture data <binary data>
+
+Picture type:
+
+ $00 Other
+ $01 32x32 pixels 'file icon' (PNG only)
+ $02 Other file icon
+ $03 Cover (front)
+ $04 Cover (back)
+ $05 Leaflet page
+ $06 Media (e.g. lable side of CD)
+ $07 Lead artist/lead performer/soloist
+ $08 Artist/performer
+ $09 Conductor
+ $0A Band/Orchestra
+ $0B Composer
+ $0C Lyricist/text writer
+ $0D Recording Location
+ $0E During recording
+ $0F During performance
+ $10 Movie/video screen capture
+ $11 A bright coloured fish
+ $12 Illustration
+ $13 Band/artist logotype
+ $14 Publisher/Studio logotype
+
+
+4.16. General encapsulated object
+
+In this frame any type of file can be encapsulated. After the header, 'Frame
+size' and 'Encoding' follows 'MIME type' represented as as a terminated string
+encoded with ISO-8859-1. The filename is case sensitive and is encoded as
+'Encoding'. Then follows a content description as terminated string, encoded as
+'Encoding'. The last thing in the frame is the actual object. The first two
+strings may be omitted, leaving only their terminations. There may be more than
+one "GEOB" frame in each tag, but only one with the same content descriptor.
+
+ <Header for 'General encapsulated object', ID: "GEOB">
+ Text encoding $xx
+ MIME type <text string> $00
+ Filename <text string according to encoding> $00 (00)
+ Content description $00 (00)
+ Encapsulated object <binary data>
+
+
+4.17. Play counter
+
+This is simply a counter of the number of times a file has been played. The
+value is increased by one every time the file begins to play. There may only be
+one "PCNT" frame in each tag. When the counter reaches all one's, one byte is
+inserted in front of the counter thus making the counter eight bits bigger. The
+counter must be at least 32-bits long to begin with.
+
+ <Header for 'Play counter', ID: "PCNT">
+ Counter $xx xx xx xx (xx ...)
+
+
+4.18. Popularimeter
+
+The purpose of this frame is to specify how good an audio file is. Many
+interesting applications could be found to this frame such as a playlist that
+features better audiofiles more often than others or it could be used to
+profile a person's taste and find other 'good' files by comparing people's
+profiles. The frame is very simple. It contains the email address to the user,
+one rating byte and a four byte play counter, intended to be increased with one
+for every time the file is played. The email is a terminated string. The rating
+is 1-255 where 1 is worst and 255 is best. 0 is unknown. If no personal counter
+is wanted it may be omitted. When the counter reaches all one's, one byte is
+inserted in front of the counter thus making the counter eight bits bigger in
+the same away as the play counter ("PCNT"). There may be more than one "POPM"
+frame in each tag, but only one with the same email address.
+
+ <Header for 'Popularimeter', ID: "POPM">
+ Email to user <text string> $00
+ Rating $xx
+ Counter $xx xx xx xx (xx ...)
+
+
+4.19. Recommended buffer size
+
+Sometimes the server from which a audio file is streamed is aware of
+transmission or coding problems resulting in interruptions in the audio stream.
+In these cases, the size of the buffer can be recommended by the server using
+this frame. If the 'embedded info flag' is true (1) then this indicates that an
+ID3 tag with the maximum size described in 'Buffer size' may occur in the
+audiostream. In such case the tag should reside between two MPEG frames, if the
+audio is MPEG encoded. If the position of the next tag is known, 'offset to
+next tag' may be used. The offset is calculated from the end of tag in which
+this frame resides to the first byte of the header in the next. This field may
+be omitted. Embedded tags are generally not recommended since this could render
+unpredictable behaviour from present software/hardware.
+For applications like streaming audio it might be an idea to embed tags into
+the audio stream though. If the clients connects to individual connections like
+HTTP and there is a possibility to begin every transmission with a tag, then
+this tag should include a 'recommended buffer size' frame. If the client is
+connected to a arbitrary point in the stream, such as radio or multicast, then
+the 'recommended buffer size' frame should be included in every tag. Every tag
+that is picked up after the initial/first tag is to be considered as an update
+of the previous one. E.g. if there is a "TIT2" frame in the first received tag
+and one in the second tag, then the first should be 'replaced' with the second.
+The 'Buffer size' should be kept to a minimum. There may only be one "RBUF"
+frame in each tag.
+
+ <Header for 'Recommended buffer size', ID: "RBUF">
+ Buffer size $xx xx xx
+ Embedded info flag %0000000x
+ Offset to next tag $xx xx xx xx
+
+
+4.20. Audio encryption
+
+This frame indicates if the actual audio stream is encrypted, and by whom.
+Since standardisation of such encrypion scheme is beyond this document, all
+"AENC" frames begin with a terminated string with a URL containing an email
+address, or a link to a location where an email address can be found, that
+belongs to the organisation responsible for this specific encrypted audio file.
+Questions regarding the encrypted audio should be sent to the email address
+specified. If a $00 is found directly after the 'Frame size' and the audiofile
+indeed is encrypted, the whole file may be considered useless.
+After the 'Owner identifier', a pointer to an unencrypted part of the audio can
+be specified. The 'Preview start' and 'Preview length' is described in frames.
+If no part is unencrypted, these fields should be left zeroed. After the
+'preview length' field follows optionally a datablock required for decryption
+of the audio. There may be more than one "AENC" frames in a tag, but only one
+with the same 'Owner identifier'.
+
+ <Header for 'Audio encryption', ID: "AENC">
+ Owner identifier <text string> $00
+ Preview start $xx xx
+ Preview length $xx xx
+ Encryption info <binary data>
+
+
+4.21. Linked information
+
+To keep space waste as low as possible this frame may be used to link
+information from another ID3v2 tag that might reside in another audio file or
+alone in a binary file. It is recommended that this method is only used when
+the files are stored on a CD-ROM or other circumstances when the risk of file
+seperation is low. The frame contains a frame identifier, which is the frame
+that should be linked into this tag, a URL field, where a reference to the file
+where the frame is given, and additional ID data, if needed. Data should be
+retrieved from the first tag found in the file to which this link points. There
+may be more than one "LINK" frame in a tag, but only one with the same
+contents. A linked frame is to be considered as part of the tag and has the
+same restrictions as if it was a physical part of the tag (i.e. only one "RVRB"
+frame allowed, whether it's linked or not).
+
+ <Header for 'Linked information', ID: "LINK">
+ Frame identifier $xx xx xx
+ URL <text string> $00
+ ID and additional data <text string(s)>
+
+Frames that may be linked and need no additional data are "IPLS", "MCID",
+"ETCO", "MLLT", "SYTC", "RVAD", "EQUA", "RVRB", "RBUF", the text information
+frames and the URL link frames.
+The "TXXX", "APIC", "GEOB" and "AENC" frames may be linked with the content
+descriptor as additional ID data.
+The "COMM", "SYLT" and "USLT" frames may be linked with three bytes of language
+descriptor directly followed by a content descriptor as additional ID data.
+
+4.22. Position synchronisation frame
+
+This frame delivers information to the listener of how far into the audio
+stream he picked up; in effect, it states the time offset of the first frame in
+the stream. The frame layout is:
+
+ <Head for 'Position synchronisation', ID: "POSS">
+ Time stamp format $xx
+ Position $xx (xx ...)
+
+Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+and position is where in the audio the listener starts to receive, i.e. the
+beginning of the next frame. If this frame is used in the beginning of a file
+the value is always 0. There may only be one "POSS" frame in each tag.
+
+4.23. Terms of use frame
+
+This frame contains a brief description of the terms of use and ownership of
+the file. More detailed information concerning the legal terms might be
+available through the "WCOP" frame. Newlines are allowed in the text. There may
+only be one "USER" frame in a tag.
+
+ <Header for 'Terms of use frame', ID: "USER">
+ Text encoding $xx
+ Language $xx xx xx
+ The actual text <text string according to encoding>
+
+
+4.24. Ownership frame
+
+The ownership frame might be used as a reminder of a made transaction or, if
+signed, as proof. Note that the "USER" and "TOWN" frames are good to use in
+conjunction with this one. The frame begins, after the frame ID, size and
+encoding fields, with a 'price payed' field. The first three characters of this
+field contains the currency used for the transaction, encoded according to ISO-
+4217 alphabetic currency code. Concatenated to this is the actual price payed,
+as a numerical string using "." as the decimal separator. Next is an 8
+character date string (YYYYMMDD) followed by a string with the name of the
+seller as the last field in the frame. There may only be one "OWNE" frame in a
+tag.
+
+ <Header for 'Ownership frame', ID: "OWNE">
+ Text encoding $xx
+ Price payed <text string> $00
+ Date of purch. <text string>
+ Seller <text string according to encoding>
+
+
+4.25. Commercial frame
+
+This frame enables several competing offers in the same tag by bundling all
+needed information. That makes this frame rather complex but it's an easier
+solution than if one tries to achieve the same result with several frames. The
+frame begins, after the frame ID, size and encoding fields, with a price string
+field. A price is constructed by one three character currency code, encoded
+according to ISO-4217 alphabetic currency code, followed by a numerical value
+where "." is used as decimal seperator. In the price string several prices may
+be concatenated, seperated by a "/" character, but there may only be one
+currency of each type.
+The price string is followed by an 8 character date string in the format
+YYYYMMDD, describing for how long the price is valid. After that is a contact
+URL, with which the user can contact the seller, followed by a one byte
+'received as' field. It describes how the audio is delivered when bought
+according to the following list:
+
+ $00 Other
+ $01 Standard CD album with other songs
+ $02 Compressed audio on CD
+ $03 File over the Internet
+ $04 Stream over the Internet
+ $05 As note sheets
+ $06 As note sheets in a book with other sheets
+ $07 Music on other media
+ $08 Non-musical merchandise
+
+Next follows a terminated string with the name of the seller followed by a
+terminated string with a short description of the product. The last thing is
+the ability to include a company logotype. The first of them is the 'Picture
+MIME type' field containing information about which picture format is used. In
+the event that the MIME media type name is omitted, "image/" will be implied.
+Currently only "image/png" and "image/jpeg" are allowed. This format string is
+followed by the binary picture data. This two last fields may be omitted if no
+picture is to attach.
+
+ <Header for 'Commercial frame', ID: "COMR">
+ Text encoding $xx
+ Price string <text string> $00
+ Valid until <text string>
+ Contact URL <text string> $00
+ Received as $xx
+ Name of seller <text string according to encoding> $00 (00)
+ Description <text string according to encoding> $00 (00)
+ Picture MIME type <string> $00
+ Seller logo <binary data>
+
+
+4.26. Encryption method registration
+
+To identify with which method a frame has been encrypted the encryption method
+must be registered in the tag with this frame. The 'Owner identifier' is a
+null-terminated string with a URL containing an email address, or a link to a
+location where an email address can be found, that belongs to the organisation
+responsible for this specific encryption method. Questions regarding the
+encryption method should be sent to the indicated email address. The 'Method
+symbol' contains a value that is associated with this method throughout the
+whole tag. Values below $80 are reserved. The 'Method symbol' may optionally be
+followed by encryption specific data. There may be several "ENCR" frames in a
+tag but only one containing the same symbol and only one containing the same
+owner identifier. The method must be used somewhere in the tag. See section
+3.3.1, flag j for more information.
+
+ <Header for 'Encryption method registration', ID: "ENCR">
+ Owner identifier <text string> $00
+ Method symbol $xx
+ Encryption data <binary data>
+
+
+4.27. Group identification registration
+
+This frame enables grouping of otherwise unrelated frames. This can be used
+when some frames are to be signed. To identify which frames belongs to a set of
+frames a group identifier must be registered in the tag with this frame. The
+'Owner identifier' is a null-terminated string with a URL containing an email
+address, or a link to a location where an email address can be found, that
+belongs to the organisation responsible for this grouping. Questions regarding
+the grouping should be sent to the indicated email address. The 'Group symbol'
+contains a value that associates the frame with this group throughout the whole
+tag. Values below $80 are reserved. The 'Group symbol' may optionally be
+followed by some group specific data, e.g. a digital signature. There may be
+several "GRID" frames in a tag but only one containing the same symbol and only
+one containing the same owner identifier. The group symbol must be used
+somewhere in the tag. See section_3.3.1, flag j for more information.
+
+ <Header for 'Group ID registration', ID: "GRID">
+ Owner identifier <text string> $00
+ Group symbol $xx
+ Group dependent data <binary data>
+
+
+4.28. Private frame
+
+This frame is used to contain information from a software producer that its
+program uses and does not fit into the other frames. The frame consists of an
+'Owner identifier' string and the binary data. The 'Owner identifier' is a
+null-terminated string with a URL containing an email address, or a link to a
+location where an email address can be found, that belongs to the organisation
+responsible for the frame. Questions regarding the frame should be sent to the
+indicated email address. The tag may contain more than one "PRIV" frame but
+only with different contents. It is recommended to keep the number of "PRIV"
+frames as low as possible.
+
+ <Header for 'Private frame', ID: "PRIV">
+ Owner identifier <text string> $00
+ The private data <binary data>
+
+
+
+5. The unsynchronisation scheme
+
+The only purpose of the 'unsynchronisation scheme' is to make the ID3v2 tag as
+compatible as possible with existing software. There is no use in
+'unsynchronising' tags if the file is only to be processed by new software.
+Unsynchronisation may only be made with MPEG 2 layer I, II and III and MPEG 2.5
+files.
+Whenever a false synchronisation is found within the tag, one zeroed byte is
+inserted after the first false synchronisation byte. The format of a correct
+sync that should be altered by ID3 encoders is as follows:
+
+ %11111111 111xxxxx
+
+And should be replaced with:
+
+ %11111111 00000000 111xxxxx
+
+This has the side effect that all $FF 00 combinations have to be altered, so
+they won't be affected by the decoding process. Therefore all the $FF 00
+combinations have to be replaced with the $FF 00 00 combination during the
+unsynchronisation.
+To indicate usage of the unsynchronisation, the first bit in 'ID3 flags' should
+be set. This bit should only be set if the tag contains a, now corrected, false
+synchronisation. The bit should only be clear if the tag does not contain any
+false synchronisations.
+Do bear in mind, that if a compression scheme is used by the encoder, the
+unsynchronisation scheme should be applied *afterwards*. When decoding a
+compressed, 'unsynchronised' file, the 'unsynchronisation scheme' should be
+parsed first, decompression afterwards.
+If the last byte in the tag is $FF, and there is a need to eliminate false
+synchronisations in the tag, at least one byte of padding should be added.
+
+
+6. Copyright
+
+Copyright © Martin Nilsson 1998. All Rights Reserved.
+This document and translations of it may be copied and furnished to others, and
+derivative works that comment on or otherwise explain it or assist in its
+implementation may be prepared, copied, published and distributed, in whole or
+in part, without restriction of any kind, provided that a reference to this
+document is included on all such copies and derivative works. However, this
+document itself may not be modified in any way and reissued as the original
+document.
+The limited permissions granted above are perpetual and will not be revoked.
+This document and the information contained herein is provided on an "AS IS"
+basis and THE AUTHORS DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
+INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR
+A PARTICULAR PURPOSE.
+
+
+7. References
+
+[CDDB] Compact Disc Data Base http://www.cddb.com
+
+[ID3v2] Martin Nilsson, "ID3v2_informal_standard".
+
+ [ISO-639-2] ISO/FDIS 639-2. Codes for the representation of names of
+languages, Part 2: Alpha-3 code. Technical committee / subcommittee: TC 37 / SC
+2
+
+ [ISO-4217] ISO 4217:1995. Codes for the representation of currencies and
+funds. Technical committee / subcommittee: TC 68
+
+ [ISO-8859-1] ISO/IEC DIS 8859-1. 8-bit single-byte coded graphic character
+sets, Part 1: Latin alphabet No. 1. Technical committee / subcommittee: JTC 1 /
+SC 2
+
+ [ISRC] ISO 3901:1986 International Standard Recording Code (ISRC). Technical
+committee / subcommittee: TC 46 / SC 9
+
+ [JFIF] JPEG File Interchange Format, version 1.02, http://www.w3.org/Graphics/
+JPEG/jfif.txt
+
+ [MIME] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions
+(MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996.,
+ftp://ftp.isi.edu/in-notes/rfc2045.txt
+
+ [MPEG] ISO/IEC 11172-3:1993. Coding of moving pictures and associated audio
+for digital storage media at up to about 1,5 Mbit/s, Part 3: Audio. Technical
+committee / subcommittee: JTC 1 / SC 29 and ISO/IEC 13818-3:1995 Generic coding
+of moving pictures and associated audio information, Part 3: Audio. Technical
+committee / subcommittee: JTC 1 / SC 29 and ISO/IEC DIS 13818-3 Generic coding
+of moving pictures and associated audio information, Part 3: Audio (Revision of
+ISO/IEC 13818-3:1995)
+
+ [PNG] Portable Network Graphics, version 1.0, http://www.w3.org/TR/REC-png-
+multi.html
+
+ [UNICODE] ISO/IEC 10646-1:1993. Universal Multiple-Octet Coded Character Set
+(UCS), Part 1: Architecture and Basic Multilingual Plane. Technical committee /
+subcommittee: JTC 1 / SC 2, http://www.unicode.org
+
+ [URL] T. Berners-Lee, L. Masinter & M. McCahill, "Uniform Resource
+Locators (URL).", RFC 1738, December 1994., ftp://ftp.isi.edu/in-notes/
+rfc1738.txt
+
+ [ZLIB] P. Deutsch, Aladdin Enterprises & J-L. Gailly, "ZLIB Compressed
+Data Format Specification version 3.3", RFC 1950, May 1996., url:ftp://
+ftp.isi.edu/in-notes/rfc1950.txt
+
+
+
+8. Appendix
+
+
+8.1. Appendix A - Genre List from ID3v1
+
+The following genres is defined in ID3v1
+
+ 0. Blues
+ 1. Classic Rock
+ 2. Country
+ 3. Dance
+ 4. Disco
+ 5. Funk
+ 6. Grunge
+ 7. Hip-Hop
+ 8. Jazz
+ 9. Metal
+ 10. New Age
+ 11. Oldies
+ 12. Other
+ 13. Pop
+ 14. R&B
+ 15. Rap
+ 16. Reggae
+ 17. Rock
+ 18. Techno
+ 19. Industrial
+ 20. Alternative
+ 21. Ska
+ 22. Death Metal
+ 23. Pranks
+ 24. Soundtrack
+ 25. Euro-Techno
+ 26. Ambient
+ 27. Trip-Hop
+ 28. Vocal
+ 29. Jazz+Funk
+ 30. Fusion
+ 31. Trance
+ 32. Classical
+ 33. Instrumental
+ 34. Acid
+ 35. House
+ 36. Game
+ 37. Sound Clip
+ 38. Gospel
+ 39. Noise
+ 40. AlternRock
+ 41. Bass
+ 42. Soul
+ 43. Punk
+ 44. Space
+ 45. Meditative
+ 46. Instrumental Pop
+ 47. Instrumental Rock
+ 48. Ethnic
+ 49. Gothic
+ 50. Darkwave
+ 51. Techno-Industrial
+ 52. Electronic
+ 53. Pop-Folk
+ 54. Eurodance
+ 55. Dream
+ 56. Southern Rock
+ 57. Comedy
+ 58. Cult
+ 59. Gangsta
+ 60. Top 40
+ 61. Christian Rap
+ 62. Pop/Funk
+ 63. Jungle
+ 64. Native American
+ 65. Cabaret
+ 66. New Wave
+ 67. Psychadelic
+ 68. Rave
+ 69. Showtunes
+ 70. Trailer
+ 71. Lo-Fi
+ 72. Tribal
+ 73. Acid Punk
+ 74. Acid Jazz
+ 75. Polka
+ 76. Retro
+ 77. Musical
+ 78. Rock & Roll
+ 79. Hard Rock
+
+The following genres are Winamp extensions
+
+ 80. Folk
+ 81. Folk-Rock
+ 82. National Folk
+ 83. Swing
+ 84. Fast Fusion
+ 85. Bebob
+ 86. Latin
+ 87. Revival
+ 88. Celtic
+ 89. Bluegrass
+ 90. Avantgarde
+ 91. Gothic Rock
+ 92. Progressive Rock
+ 93. Psychedelic Rock
+ 94. Symphonic Rock
+ 95. Slow Rock
+ 96. Big Band
+ 97. Chorus
+ 98. Easy Listening
+ 99. Acoustic
+ 100. Humour
+ 101. Speech
+ 102. Chanson
+ 103. Opera
+ 104. Chamber Music
+ 105. Sonata
+ 106. Symphony
+ 107. Booty Bass
+ 108. Primus
+ 109. Porn Groove
+ 110. Satire
+ 111. Slow Jam
+ 112. Club
+ 113. Tango
+ 114. Samba
+ 115. Folklore
+ 116. Ballad
+ 117. Power Ballad
+ 118. Rhythmic Soul
+ 119. Freestyle
+ 120. Duet
+ 121. Punk Rock
+ 122. Drum Solo
+ 123. A capella
+ 124. Euro-House
+ 125. Dance Hall
+
+
+
+9. Author's Address
+
+Written by
+Martin Nilsson
+Rydsven 246 C. 30
+S-584 34 Linkoping
+Sweden
+
+Email: nilsson at id3.org
+
+Edited by
+Dirk Mahoney
+57 Pechey Street
+Chermside Q
+Australia 4032
+
+Email: dirk at id3.org
+
+Johan Sundstrom
+Alsttersgatan 5 A. 34
+S-584 35 Linkoping
+Sweden
+
+Email: johan at id3.org
+id3v2.3.0 (last edited 2006-12-18 06:25:16 by DanONeill)
--- /dev/null
+$Id$
+
+Informal standard M. Nilsson
+Document: id3v2.4.0-frames.txt 1st November 2000
+
+
+ ID3 tag version 2.4.0 - Native Frames
+
+Status of this document
+
+ This document is an informal standard and replaces the ID3v2.3.0
+ standard [ID3v2]. A formal standard will use another revision number
+ even if the content is identical to document. The contents in this
+ document may change for clarifications but never for added or altered
+ functionallity.
+
+ Distribution of this document is unlimited.
+
+
+Abstract
+
+ This document describes the frames natively supported by ID3v2.4.0,
+ which is a revised version of the ID3v2 informal standard [ID3v2.3.0]
+ version 2.3.0. The ID3v2 offers a flexible way of storing audio meta
+ information within audio file itself. The information may be
+ technical information, such as equalisation curves, as well as title,
+ performer, copyright etc.
+
+ ID3v2.4.0 is meant to be as close as possible to ID3v2.3.0 in order
+ to allow for implementations to be revised as easily as possible.
+
+
+1. Table of contents
+
+ 2. Conventions in this document
+ 3. Default flags
+ 4. Declared ID3v2 frames
+ 4.1. Unique file identifier
+ 4.2. Text information frames
+ 4.2.1. Identification frames
+ 4.2.2. Involved persons frames
+ 4.2.3. Derived and subjective properties frames
+ 4.2.4. Rights and license frames
+ 4.2.5. Other text frames
+ 4.2.6. User defined text information frame
+ 4.3. URL link frames
+ 4.3.1. URL link frames - details
+ 4.3.2. User defined URL link frame
+ 4.4. Music CD Identifier
+ 4.5. Event timing codes
+ 4.6. MPEG location lookup table
+ 4.7. Synced tempo codes
+ 4.8. Unsynchronised lyrics/text transcription
+ 4.9. Synchronised lyrics/text
+ 4.10. Comments
+ 4.11. Relative volume adjustment (2)
+ 4.12. Equalisation (2)
+ 4.13. Reverb
+ 4.14. Attached picture
+ 4.15. General encapsulated object
+ 4.16. Play counter
+ 4.17. Popularimeter
+ 4.18. Recommended buffer size
+ 4.19. Audio encryption
+ 4.20. Linked information
+ 4.21. Position synchronisation frame
+ 4.22. Terms of use
+ 4.23. Ownership frame
+ 4.24. Commercial frame
+ 4.25. Encryption method registration
+ 4.26. Group identification registration
+ 4.27. Private frame
+ 4.28. Signature frame
+ 4.29. Seek frame
+ 4.30. Audio seek point index
+ 5. Copyright
+ 6. References
+ 7. Appendix
+ A. Appendix A - Genre List from ID3v1
+ 8. Author's Address
+
+
+2. Conventions in this document
+
+ Text within "" is a text string exactly as it appears in a tag.
+ Numbers preceded with $ are hexadecimal and numbers preceded with %
+ are binary. $xx is used to indicate a byte with unknown content. %x
+ is used to indicate a bit with unknown content. The most significant
+ bit (MSB) of a byte is called 'bit 7' and the least significant bit
+ (LSB) is called 'bit 0'.
+
+ A tag is the whole tag described the ID3v2 main structure document
+ [ID3v2-strct]. A frame is a block of information in the tag. The tag
+ consists of a header, frames and optional padding. A field is a piece
+ of information; one value, a string etc. A numeric string is a string
+ that consists of the characters "0123456789" only.
+
+ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+ "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+ document are to be interpreted as described in RFC 2119 [KEYWORDS].
+
+
+3. Default flags
+
+ The default settings for the frames described in this document can be
+ divided into the following classes. The flags may be set differently
+ if found more suitable by the software.
+
+ 1. Discarded if tag is altered, discarded if file is altered.
+
+ None.
+
+ 2. Discarded if tag is altered, preserved if file is altered.
+
+ None.
+
+ 3. Preserved if tag is altered, discarded if file is altered.
+
+ ASPI, AENC, ETCO, EQU2, MLLT, POSS, SEEK, SYLT, SYTC, RVA2, TENC,
+ TLEN
+
+ 4. Preserved if tag is altered, preserved if file is altered.
+
+ The rest of the frames.
+
+
+4. Declared ID3v2 frames
+
+ The following frames are declared in this draft.
+
+ 4.19 AENC Audio encryption
+ 4.14 APIC Attached picture
+ 4.30 ASPI Audio seek point index
+
+ 4.10 COMM Comments
+ 4.24 COMR Commercial frame
+
+ 4.25 ENCR Encryption method registration
+ 4.12 EQU2 Equalisation (2)
+ 4.5 ETCO Event timing codes
+
+ 4.15 GEOB General encapsulated object
+ 4.26 GRID Group identification registration
+
+ 4.20 LINK Linked information
+
+ 4.4 MCDI Music CD identifier
+ 4.6 MLLT MPEG location lookup table
+
+ 4.23 OWNE Ownership frame
+
+ 4.27 PRIV Private frame
+ 4.16 PCNT Play counter
+ 4.17 POPM Popularimeter
+ 4.21 POSS Position synchronisation frame
+
+ 4.18 RBUF Recommended buffer size
+ 4.11 RVA2 Relative volume adjustment (2)
+ 4.13 RVRB Reverb
+
+ 4.29 SEEK Seek frame
+ 4.28 SIGN Signature frame
+ 4.9 SYLT Synchronised lyric/text
+ 4.7 SYTC Synchronised tempo codes
+
+ 4.2.1 TALB Album/Movie/Show title
+ 4.2.3 TBPM BPM (beats per minute)
+ 4.2.2 TCOM Composer
+ 4.2.3 TCON Content type
+ 4.2.4 TCOP Copyright message
+ 4.2.5 TDEN Encoding time
+ 4.2.5 TDLY Playlist delay
+ 4.2.5 TDOR Original release time
+ 4.2.5 TDRC Recording time
+ 4.2.5 TDRL Release time
+ 4.2.5 TDTG Tagging time
+ 4.2.2 TENC Encoded by
+ 4.2.2 TEXT Lyricist/Text writer
+ 4.2.3 TFLT File type
+ 4.2.2 TIPL Involved people list
+ 4.2.1 TIT1 Content group description
+ 4.2.1 TIT2 Title/songname/content description
+ 4.2.1 TIT3 Subtitle/Description refinement
+ 4.2.3 TKEY Initial key
+ 4.2.3 TLAN Language(s)
+ 4.2.3 TLEN Length
+ 4.2.2 TMCL Musician credits list
+ 4.2.3 TMED Media type
+ 4.2.3 TMOO Mood
+ 4.2.1 TOAL Original album/movie/show title
+ 4.2.5 TOFN Original filename
+ 4.2.2 TOLY Original lyricist(s)/text writer(s)
+ 4.2.2 TOPE Original artist(s)/performer(s)
+ 4.2.4 TOWN File owner/licensee
+ 4.2.2 TPE1 Lead performer(s)/Soloist(s)
+ 4.2.2 TPE2 Band/orchestra/accompaniment
+ 4.2.2 TPE3 Conductor/performer refinement
+ 4.2.2 TPE4 Interpreted, remixed, or otherwise modified by
+ 4.2.1 TPOS Part of a set
+ 4.2.4 TPRO Produced notice
+ 4.2.4 TPUB Publisher
+ 4.2.1 TRCK Track number/Position in set
+ 4.2.4 TRSN Internet radio station name
+ 4.2.4 TRSO Internet radio station owner
+ 4.2.5 TSOA Album sort order
+ 4.2.5 TSOP Performer sort order
+ 4.2.5 TSOT Title sort order
+ 4.2.1 TSRC ISRC (international standard recording code)
+ 4.2.5 TSSE Software/Hardware and settings used for encoding
+ 4.2.1 TSST Set subtitle
+ 4.2.2 TXXX User defined text information frame
+
+ 4.1 UFID Unique file identifier
+ 4.22 USER Terms of use
+ 4.8 USLT Unsynchronised lyric/text transcription
+
+ 4.3.1 WCOM Commercial information
+ 4.3.1 WCOP Copyright/Legal information
+ 4.3.1 WOAF Official audio file webpage
+ 4.3.1 WOAR Official artist/performer webpage
+ 4.3.1 WOAS Official audio source webpage
+ 4.3.1 WORS Official Internet radio station homepage
+ 4.3.1 WPAY Payment
+ 4.3.1 WPUB Publishers official webpage
+ 4.3.2 WXXX User defined URL link frame
+
+
+4.1. Unique file identifier
+
+ This frame's purpose is to be able to identify the audio file in a
+ database, that may provide more information relevant to the content.
+ Since standardisation of such a database is beyond this document, all
+ UFID frames begin with an 'owner identifier' field. It is a null-
+ terminated string with a URL [URL] containing an email address, or a
+ link to a location where an email address can be found, that belongs
+ to the organisation responsible for this specific database
+ implementation. Questions regarding the database should be sent to
+ the indicated email address. The URL should not be used for the
+ actual database queries. The string
+ "http://www.id3.org/dummy/ufid.html" should be used for tests. The
+ 'Owner identifier' must be non-empty (more than just a termination).
+ The 'Owner identifier' is then followed by the actual identifier,
+ which may be up to 64 bytes. There may be more than one "UFID" frame
+ in a tag, but only one with the same 'Owner identifier'.
+
+ <Header for 'Unique file identifier', ID: "UFID">
+ Owner identifier <text string> $00
+ Identifier <up to 64 bytes binary data>
+
+
+4.2. Text information frames
+
+ The text information frames are often the most important frames,
+ containing information like artist, album and more. There may only be
+ one text information frame of its kind in an tag. All text
+ information frames supports multiple strings, stored as a null
+ separated list, where null is reperesented by the termination code
+ for the charater encoding. All text frame identifiers begin with "T".
+ Only text frame identifiers begin with "T", with the exception of the
+ "TXXX" frame. All the text information frames have the following
+ format:
+
+ <Header for 'Text information frame', ID: "T000" - "TZZZ",
+ excluding "TXXX" described in 4.2.6.>
+ Text encoding $xx
+ Information <text string(s) according to encoding>
+
+
+4.2.1. Identification frames
+
+ TIT1
+ The 'Content group description' frame is used if the sound belongs to
+ a larger category of sounds/music. For example, classical music is
+ often sorted in different musical sections (e.g. "Piano Concerto",
+ "Weather - Hurricane").
+
+ TIT2
+ The 'Title/Songname/Content description' frame is the actual name of
+ the piece (e.g. "Adagio", "Hurricane Donna").
+
+ TIT3
+ The 'Subtitle/Description refinement' frame is used for information
+ directly related to the contents title (e.g. "Op. 16" or "Performed
+ live at Wembley").
+
+ TALB
+ The 'Album/Movie/Show title' frame is intended for the title of the
+ recording (or source of sound) from which the audio in the file is
+ taken.
+
+ TOAL
+ The 'Original album/movie/show title' frame is intended for the title
+ of the original recording (or source of sound), if for example the
+ music in the file should be a cover of a previously released song.
+
+ TRCK
+ The 'Track number/Position in set' frame is a numeric string
+ containing the order number of the audio-file on its original
+ recording. This MAY be extended with a "/" character and a numeric
+ string containing the total number of tracks/elements on the original
+ recording. E.g. "4/9".
+
+ TPOS
+ The 'Part of a set' frame is a numeric string that describes which
+ part of a set the audio came from. This frame is used if the source
+ described in the "TALB" frame is divided into several mediums, e.g. a
+ double CD. The value MAY be extended with a "/" character and a
+ numeric string containing the total number of parts in the set. E.g.
+ "1/2".
+
+ TSST
+ The 'Set subtitle' frame is intended for the subtitle of the part of
+ a set this track belongs to.
+
+ TSRC
+ The 'ISRC' frame should contain the International Standard Recording
+ Code [ISRC] (12 characters).
+
+
+4.2.2. Involved persons frames
+
+ TPE1
+ The 'Lead artist/Lead performer/Soloist/Performing group' is
+ used for the main artist.
+
+ TPE2
+ The 'Band/Orchestra/Accompaniment' frame is used for additional
+ information about the performers in the recording.
+
+ TPE3
+ The 'Conductor' frame is used for the name of the conductor.
+
+ TPE4
+ The 'Interpreted, remixed, or otherwise modified by' frame contains
+ more information about the people behind a remix and similar
+ interpretations of another existing piece.
+
+ TOPE
+ The 'Original artist/performer' frame is intended for the performer
+ of the original recording, if for example the music in the file
+ should be a cover of a previously released song.
+
+ TEXT
+ The 'Lyricist/Text writer' frame is intended for the writer of the
+ text or lyrics in the recording.
+
+ TOLY
+ The 'Original lyricist/text writer' frame is intended for the
+ text writer of the original recording, if for example the music in
+ the file should be a cover of a previously released song.
+
+ TCOM
+ The 'Composer' frame is intended for the name of the composer.
+
+ TMCL
+ The 'Musician credits list' is intended as a mapping between
+ instruments and the musician that played it. Every odd field is an
+ instrument and every even is an artist or a comma delimited list of
+ artists.
+
+ TIPL
+ The 'Involved people list' is very similar to the musician credits
+ list, but maps between functions, like producer, and names.
+
+ TENC
+ The 'Encoded by' frame contains the name of the person or
+ organisation that encoded the audio file. This field may contain a
+ copyright message, if the audio file also is copyrighted by the
+ encoder.
+
+
+4.2.3. Derived and subjective properties frames
+
+ TBPM
+ The 'BPM' frame contains the number of beats per minute in the
+ main part of the audio. The BPM is an integer and represented as a
+ numerical string.
+
+ TLEN
+ The 'Length' frame contains the length of the audio file in
+ milliseconds, represented as a numeric string.
+
+ TKEY
+ The 'Initial key' frame contains the musical key in which the sound
+ starts. It is represented as a string with a maximum length of three
+ characters. The ground keys are represented with "A","B","C","D","E",
+ "F" and "G" and halfkeys represented with "b" and "#". Minor is
+ represented as "m", e.g. "Dbm" $00. Off key is represented with an
+ "o" only.
+
+ TLAN
+ The 'Language' frame should contain the languages of the text or
+ lyrics spoken or sung in the audio. The language is represented with
+ three characters according to ISO-639-2 [ISO-639-2]. If more than one
+ language is used in the text their language codes should follow
+ according to the amount of their usage, e.g. "eng" $00 "sve" $00.
+
+ TCON
+ The 'Content type', which ID3v1 was stored as a one byte numeric
+ value only, is now a string. You may use one or several of the ID3v1
+ types as numerical strings, or, since the category list would be
+ impossible to maintain with accurate and up to date categories,
+ define your own. Example: "21" $00 "Eurodisco" $00
+
+ You may also use any of the following keywords:
+
+ RX Remix
+ CR Cover
+
+ TFLT
+ The 'File type' frame indicates which type of audio this tag defines.
+ The following types and refinements are defined:
+
+ MIME MIME type follows
+ MPG MPEG Audio
+ /1 MPEG 1/2 layer I
+ /2 MPEG 1/2 layer II
+ /3 MPEG 1/2 layer III
+ /2.5 MPEG 2.5
+ /AAC Advanced audio compression
+ VQF Transform-domain Weighted Interleave Vector Quantisation
+ PCM Pulse Code Modulated audio
+
+ but other types may be used, but not for these types though. This is
+ used in a similar way to the predefined types in the "TMED" frame,
+ but without parentheses. If this frame is not present audio type is
+ assumed to be "MPG".
+
+ TMED
+ The 'Media type' frame describes from which media the sound
+ originated. This may be a text string or a reference to the
+ predefined media types found in the list below. Example:
+ "VID/PAL/VHS" $00.
+
+ DIG Other digital media
+ /A Analogue transfer from media
+
+ ANA Other analogue media
+ /WAC Wax cylinder
+ /8CA 8-track tape cassette
+
+ CD CD
+ /A Analogue transfer from media
+ /DD DDD
+ /AD ADD
+ /AA AAD
+
+ LD Laserdisc
+
+ TT Turntable records
+ /33 33.33 rpm
+ /45 45 rpm
+ /71 71.29 rpm
+ /76 76.59 rpm
+ /78 78.26 rpm
+ /80 80 rpm
+
+ MD MiniDisc
+ /A Analogue transfer from media
+
+ DAT DAT
+ /A Analogue transfer from media
+ /1 standard, 48 kHz/16 bits, linear
+ /2 mode 2, 32 kHz/16 bits, linear
+ /3 mode 3, 32 kHz/12 bits, non-linear, low speed
+ /4 mode 4, 32 kHz/12 bits, 4 channels
+ /5 mode 5, 44.1 kHz/16 bits, linear
+ /6 mode 6, 44.1 kHz/16 bits, 'wide track' play
+
+ DCC DCC
+ /A Analogue transfer from media
+
+ DVD DVD
+ /A Analogue transfer from media
+
+ TV Television
+ /PAL PAL
+ /NTSC NTSC
+ /SECAM SECAM
+
+ VID Video
+ /PAL PAL
+ /NTSC NTSC
+ /SECAM SECAM
+ /VHS VHS
+ /SVHS S-VHS
+ /BETA BETAMAX
+
+ RAD Radio
+ /FM FM
+ /AM AM
+ /LW LW
+ /MW MW
+
+ TEL Telephone
+ /I ISDN
+
+ MC MC (normal cassette)
+ /4 4.75 cm/s (normal speed for a two sided cassette)
+ /9 9.5 cm/s
+ /I Type I cassette (ferric/normal)
+ /II Type II cassette (chrome)
+ /III Type III cassette (ferric chrome)
+ /IV Type IV cassette (metal)
+
+ REE Reel
+ /9 9.5 cm/s
+ /19 19 cm/s
+ /38 38 cm/s
+ /76 76 cm/s
+ /I Type I cassette (ferric/normal)
+ /II Type II cassette (chrome)
+ /III Type III cassette (ferric chrome)
+ /IV Type IV cassette (metal)
+
+ TMOO
+ The 'Mood' frame is intended to reflect the mood of the audio with a
+ few keywords, e.g. "Romantic" or "Sad".
+
+
+4.2.4. Rights and license frames
+
+ TCOP
+ The 'Copyright message' frame, in which the string must begin with a
+ year and a space character (making five characters), is intended for
+ the copyright holder of the original sound, not the audio file
+ itself. The absence of this frame means only that the copyright
+ information is unavailable or has been removed, and must not be
+ interpreted to mean that the audio is public domain. Every time this
+ field is displayed the field must be preceded with "Copyright " (C) "
+ ", where (C) is one character showing a C in a circle.
+
+ TPRO
+ The 'Produced notice' frame, in which the string must begin with a
+ year and a space character (making five characters), is intended for
+ the production copyright holder of the original sound, not the audio
+ file itself. The absence of this frame means only that the production
+ copyright information is unavailable or has been removed, and must
+ not be interpreted to mean that the audio is public domain. Every
+ time this field is displayed the field must be preceded with
+ "Produced " (P) " ", where (P) is one character showing a P in a
+ circle.
+
+ TPUB
+ The 'Publisher' frame simply contains the name of the label or
+ publisher.
+
+ TOWN
+ The 'File owner/licensee' frame contains the name of the owner or
+ licensee of the file and it's contents.
+
+ TRSN
+ The 'Internet radio station name' frame contains the name of the
+ internet radio station from which the audio is streamed.
+
+ TRSO
+ The 'Internet radio station owner' frame contains the name of the
+ owner of the internet radio station from which the audio is
+ streamed.
+
+4.2.5. Other text frames
+
+ TOFN
+ The 'Original filename' frame contains the preferred filename for the
+ file, since some media doesn't allow the desired length of the
+ filename. The filename is case sensitive and includes its suffix.
+
+ TDLY
+ The 'Playlist delay' defines the numbers of milliseconds of silence
+ that should be inserted before this audio. The value zero indicates
+ that this is a part of a multifile audio track that should be played
+ continuously.
+
+ TDEN
+ The 'Encoding time' frame contains a timestamp describing when the
+ audio was encoded. Timestamp format is described in the ID3v2
+ structure document [ID3v2-strct].
+
+ TDOR
+ The 'Original release time' frame contains a timestamp describing
+ when the original recording of the audio was released. Timestamp
+ format is described in the ID3v2 structure document [ID3v2-strct].
+
+ TDRC
+ The 'Recording time' frame contains a timestamp describing when the
+ audio was recorded. Timestamp format is described in the ID3v2
+ structure document [ID3v2-strct].
+
+ TDRL
+ The 'Release time' frame contains a timestamp describing when the
+ audio was first released. Timestamp format is described in the ID3v2
+ structure document [ID3v2-strct].
+
+ TDTG
+ The 'Tagging time' frame contains a timestamp describing then the
+ audio was tagged. Timestamp format is described in the ID3v2
+ structure document [ID3v2-strct].
+
+ TSSE
+ The 'Software/Hardware and settings used for encoding' frame
+ includes the used audio encoder and its settings when the file was
+ encoded. Hardware refers to hardware encoders, not the computer on
+ which a program was run.
+
+ TSOA
+ The 'Album sort order' frame defines a string which should be used
+ instead of the album name (TALB) for sorting purposes. E.g. an album
+ named "A Soundtrack" might preferably be sorted as "Soundtrack".
+
+ TSOP
+ The 'Performer sort order' frame defines a string which should be
+ used instead of the performer (TPE2) for sorting purposes.
+
+ TSOT
+ The 'Title sort order' frame defines a string which should be used
+ instead of the title (TIT2) for sorting purposes.
+
+
+4.2.6. User defined text information frame
+
+ This frame is intended for one-string text information concerning the
+ audio file in a similar way to the other "T"-frames. The frame body
+ consists of a description of the string, represented as a terminated
+ string, followed by the actual string. There may be more than one
+ "TXXX" frame in each tag, but only one with the same description.
+
+ <Header for 'User defined text information frame', ID: "TXXX">
+ Text encoding $xx
+ Description <text string according to encoding> $00 (00)
+ Value <text string according to encoding>
+
+
+4.3. URL link frames
+
+ With these frames dynamic data such as webpages with touring
+ information, price information or plain ordinary news can be added to
+ the tag. There may only be one URL [URL] link frame of its kind in an
+ tag, except when stated otherwise in the frame description. If the
+ text string is followed by a string termination, all the following
+ information should be ignored and not be displayed. All URL link
+ frame identifiers begins with "W". Only URL link frame identifiers
+ begins with "W", except for "WXXX". All URL link frames have the
+ following format:
+
+ <Header for 'URL link frame', ID: "W000" - "WZZZ", excluding "WXXX"
+ described in 4.3.2.>
+ URL <text string>
+
+
+4.3.1. URL link frames - details
+
+ WCOM
+ The 'Commercial information' frame is a URL pointing at a webpage
+ with information such as where the album can be bought. There may be
+ more than one "WCOM" frame in a tag, but not with the same content.
+
+ WCOP
+ The 'Copyright/Legal information' frame is a URL pointing at a
+ webpage where the terms of use and ownership of the file is
+ described.
+
+ WOAF
+ The 'Official audio file webpage' frame is a URL pointing at a file
+ specific webpage.
+
+ WOAR
+ The 'Official artist/performer webpage' frame is a URL pointing at
+ the artists official webpage. There may be more than one "WOAR" frame
+ in a tag if the audio contains more than one performer, but not with
+ the same content.
+
+ WOAS
+ The 'Official audio source webpage' frame is a URL pointing at the
+ official webpage for the source of the audio file, e.g. a movie.
+
+ WORS
+ The 'Official Internet radio station homepage' contains a URL
+ pointing at the homepage of the internet radio station.
+
+ WPAY
+ The 'Payment' frame is a URL pointing at a webpage that will handle
+ the process of paying for this file.
+
+ WPUB
+ The 'Publishers official webpage' frame is a URL pointing at the
+ official webpage for the publisher.
+
+
+4.3.2. User defined URL link frame
+
+ This frame is intended for URL [URL] links concerning the audio file
+ in a similar way to the other "W"-frames. The frame body consists
+ of a description of the string, represented as a terminated string,
+ followed by the actual URL. The URL is always encoded with ISO-8859-1
+ [ISO-8859-1]. There may be more than one "WXXX" frame in each tag,
+ but only one with the same description.
+
+ <Header for 'User defined URL link frame', ID: "WXXX">
+ Text encoding $xx
+ Description <text string according to encoding> $00 (00)
+ URL <text string>
+
+
+4.4. Music CD identifier
+
+ This frame is intended for music that comes from a CD, so that the CD
+ can be identified in databases such as the CDDB [CDDB]. The frame
+ consists of a binary dump of the Table Of Contents, TOC, from the CD,
+ which is a header of 4 bytes and then 8 bytes/track on the CD plus 8
+ bytes for the 'lead out', making a maximum of 804 bytes. The offset
+ to the beginning of every track on the CD should be described with a
+ four bytes absolute CD-frame address per track, and not with absolute
+ time. When this frame is used the presence of a valid "TRCK" frame is
+ REQUIRED, even if the CD's only got one track. It is recommended that
+ this frame is always added to tags originating from CDs. There may
+ only be one "MCDI" frame in each tag.
+
+ <Header for 'Music CD identifier', ID: "MCDI">
+ CD TOC <binary data>
+
+
+4.5. Event timing codes
+
+ This frame allows synchronisation with key events in the audio. The
+ header is:
+
+ <Header for 'Event timing codes', ID: "ETCO">
+ Time stamp format $xx
+
+ Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+ Absolute time means that every stamp contains the time from the
+ beginning of the file.
+
+ Followed by a list of key events in the following format:
+
+ Type of event $xx
+ Time stamp $xx (xx ...)
+
+ The 'Time stamp' is set to zero if directly at the beginning of the
+ sound or after the previous event. All events MUST be sorted in
+ chronological order. The type of event is as follows:
+
+ $00 padding (has no meaning)
+ $01 end of initial silence
+ $02 intro start
+ $03 main part start
+ $04 outro start
+ $05 outro end
+ $06 verse start
+ $07 refrain start
+ $08 interlude start
+ $09 theme start
+ $0A variation start
+ $0B key change
+ $0C time change
+ $0D momentary unwanted noise (Snap, Crackle & Pop)
+ $0E sustained noise
+ $0F sustained noise end
+ $10 intro end
+ $11 main part end
+ $12 verse end
+ $13 refrain end
+ $14 theme end
+ $15 profanity
+ $16 profanity end
+
+ $17-$DF reserved for future use
+
+ $E0-$EF not predefined synch 0-F
+
+ $F0-$FC reserved for future use
+
+ $FD audio end (start of silence)
+ $FE audio file ends
+ $FF one more byte of events follows (all the following bytes with
+ the value $FF have the same function)
+
+ Terminating the start events such as "intro start" is OPTIONAL. The
+ 'Not predefined synch's ($E0-EF) are for user events. You might want
+ to synchronise your music to something, like setting off an explosion
+ on-stage, activating a screensaver etc.
+
+ There may only be one "ETCO" frame in each tag.
+
+
+4.6. MPEG location lookup table
+
+ To increase performance and accuracy of jumps within a MPEG [MPEG]
+ audio file, frames with time codes in different locations in the file
+ might be useful. This ID3v2 frame includes references that the
+ software can use to calculate positions in the file. After the frame
+ header follows a descriptor of how much the 'frame counter' should be
+ increased for every reference. If this value is two then the first
+ reference points out the second frame, the 2nd reference the 4th
+ frame, the 3rd reference the 6th frame etc. In a similar way the
+ 'bytes between reference' and 'milliseconds between reference' points
+ out bytes and milliseconds respectively.
+
+ Each reference consists of two parts; a certain number of bits, as
+ defined in 'bits for bytes deviation', that describes the difference
+ between what is said in 'bytes between reference' and the reality and
+ a certain number of bits, as defined in 'bits for milliseconds
+ deviation', that describes the difference between what is said in
+ 'milliseconds between reference' and the reality. The number of bits
+ in every reference, i.e. 'bits for bytes deviation'+'bits for
+ milliseconds deviation', must be a multiple of four. There may only
+ be one "MLLT" frame in each tag.
+
+ <Header for 'Location lookup table', ID: "MLLT">
+ MPEG frames between reference $xx xx
+ Bytes between reference $xx xx xx
+ Milliseconds between reference $xx xx xx
+ Bits for bytes deviation $xx
+ Bits for milliseconds dev. $xx
+
+ Then for every reference the following data is included;
+
+ Deviation in bytes %xxx....
+ Deviation in milliseconds %xxx....
+
+
+4.7. Synchronised tempo codes
+
+ For a more accurate description of the tempo of a musical piece, this
+ frame might be used. After the header follows one byte describing
+ which time stamp format should be used. Then follows one or more
+ tempo codes. Each tempo code consists of one tempo part and one time
+ part. The tempo is in BPM described with one or two bytes. If the
+ first byte has the value $FF, one more byte follows, which is added
+ to the first giving a range from 2 - 510 BPM, since $00 and $01 is
+ reserved. $00 is used to describe a beat-free time period, which is
+ not the same as a music-free time period. $01 is used to indicate one
+ single beat-stroke followed by a beat-free period.
+
+ The tempo descriptor is followed by a time stamp. Every time the
+ tempo in the music changes, a tempo descriptor may indicate this for
+ the player. All tempo descriptors MUST be sorted in chronological
+ order. The first beat-stroke in a time-period is at the same time as
+ the beat description occurs. There may only be one "SYTC" frame in
+ each tag.
+
+ <Header for 'Synchronised tempo codes', ID: "SYTC">
+ Time stamp format $xx
+ Tempo data <binary data>
+
+ Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+ Absolute time means that every stamp contains the time from the
+ beginning of the file.
+
+
+4.8. Unsynchronised lyrics/text transcription
+
+ This frame contains the lyrics of the song or a text transcription of
+ other vocal activities. The head includes an encoding descriptor and
+ a content descriptor. The body consists of the actual text. The
+ 'Content descriptor' is a terminated string. If no descriptor is
+ entered, 'Content descriptor' is $00 (00) only. Newline characters
+ are allowed in the text. There may be more than one 'Unsynchronised
+ lyrics/text transcription' frame in each tag, but only one with the
+ same language and content descriptor.
+
+ <Header for 'Unsynchronised lyrics/text transcription', ID: "USLT">
+ Text encoding $xx
+ Language $xx xx xx
+ Content descriptor <text string according to encoding> $00 (00)
+ Lyrics/text <full text string according to encoding>
+
+
+4.9. Synchronised lyrics/text
+
+ This is another way of incorporating the words, said or sung lyrics,
+ in the audio file as text, this time, however, in sync with the
+ audio. It might also be used to describing events e.g. occurring on a
+ stage or on the screen in sync with the audio. The header includes a
+ content descriptor, represented with as terminated text string. If no
+ descriptor is entered, 'Content descriptor' is $00 (00) only.
+
+ <Header for 'Synchronised lyrics/text', ID: "SYLT">
+ Text encoding $xx
+ Language $xx xx xx
+ Time stamp format $xx
+ Content type $xx
+ Content descriptor <text string according to encoding> $00 (00)
+
+ Content type: $00 is other
+ $01 is lyrics
+ $02 is text transcription
+ $03 is movement/part name (e.g. "Adagio")
+ $04 is events (e.g. "Don Quijote enters the stage")
+ $05 is chord (e.g. "Bb F Fsus")
+ $06 is trivia/'pop up' information
+ $07 is URLs to webpages
+ $08 is URLs to images
+
+ Time stamp format:
+
+ $01 Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+ Absolute time means that every stamp contains the time from the
+ beginning of the file.
+
+ The text that follows the frame header differs from that of the
+ unsynchronised lyrics/text transcription in one major way. Each
+ syllable (or whatever size of text is considered to be convenient by
+ the encoder) is a null terminated string followed by a time stamp
+ denoting where in the sound file it belongs. Each sync thus has the
+ following structure:
+
+ Terminated text to be synced (typically a syllable)
+ Sync identifier (terminator to above string) $00 (00)
+ Time stamp $xx (xx ...)
+
+ The 'time stamp' is set to zero or the whole sync is omitted if
+ located directly at the beginning of the sound. All time stamps
+ should be sorted in chronological order. The sync can be considered
+ as a validator of the subsequent string.
+
+ Newline characters are allowed in all "SYLT" frames and MUST be used
+ after every entry (name, event etc.) in a frame with the content type
+ $03 - $04.
+
+ A few considerations regarding whitespace characters: Whitespace
+ separating words should mark the beginning of a new word, thus
+ occurring in front of the first syllable of a new word. This is also
+ valid for new line characters. A syllable followed by a comma should
+ not be broken apart with a sync (both the syllable and the comma
+ should be before the sync).
+
+ An example: The "USLT" passage
+
+ "Strangers in the night" $0A "Exchanging glances"
+
+ would be "SYLT" encoded as:
+
+ "Strang" $00 xx xx "ers" $00 xx xx " in" $00 xx xx " the" $00 xx xx
+ " night" $00 xx xx 0A "Ex" $00 xx xx "chang" $00 xx xx "ing" $00 xx
+ xx "glan" $00 xx xx "ces" $00 xx xx
+
+ There may be more than one "SYLT" frame in each tag, but only one
+ with the same language and content descriptor.
+
+
+4.10. Comments
+
+ This frame is intended for any kind of full text information that
+ does not fit in any other frame. It consists of a frame header
+ followed by encoding, language and content descriptors and is ended
+ with the actual comment as a text string. Newline characters are
+ allowed in the comment text string. There may be more than one
+ comment frame in each tag, but only one with the same language and
+ content descriptor.
+
+ <Header for 'Comment', ID: "COMM">
+ Text encoding $xx
+ Language $xx xx xx
+ Short content descrip. <text string according to encoding> $00 (00)
+ The actual text <full text string according to encoding>
+
+
+4.11. Relative volume adjustment (2)
+
+ This is a more subjective frame than the previous ones. It allows the
+ user to say how much he wants to increase/decrease the volume on each
+ channel when the file is played. The purpose is to be able to align
+ all files to a reference volume, so that you don't have to change the
+ volume constantly. This frame may also be used to balance adjust the
+ audio. The volume adjustment is encoded as a fixed point decibel
+ value, 16 bit signed integer representing (adjustment*512), giving
+ +/- 64 dB with a precision of 0.001953125 dB. E.g. +2 dB is stored as
+ $04 00 and -2 dB is $FC 00. There may be more than one "RVA2" frame
+ in each tag, but only one with the same identification string.
+
+ <Header for 'Relative volume adjustment (2)', ID: "RVA2">
+ Identification <text string> $00
+
+ The 'identification' string is used to identify the situation and/or
+ device where this adjustment should apply. The following is then
+ repeated for every channel
+
+ Type of channel $xx
+ Volume adjustment $xx xx
+ Bits representing peak $xx
+ Peak volume $xx (xx ...)
+
+
+ Type of channel: $00 Other
+ $01 Master volume
+ $02 Front right
+ $03 Front left
+ $04 Back right
+ $05 Back left
+ $06 Front centre
+ $07 Back centre
+ $08 Subwoofer
+
+ Bits representing peak can be any number between 0 and 255. 0 means
+ that there is no peak volume field. The peak volume field is always
+ padded to whole bytes, setting the most significant bits to zero.
+
+
+4.12. Equalisation (2)
+
+ This is another subjective, alignment frame. It allows the user to
+ predefine an equalisation curve within the audio file. There may be
+ more than one "EQU2" frame in each tag, but only one with the same
+ identification string.
+
+ <Header of 'Equalisation (2)', ID: "EQU2">
+ Interpolation method $xx
+ Identification <text string> $00
+
+ The 'interpolation method' describes which method is preferred when
+ an interpolation between the adjustment point that follows. The
+ following methods are currently defined:
+
+ $00 Band
+ No interpolation is made. A jump from one adjustment level to
+ another occurs in the middle between two adjustment points.
+ $01 Linear
+ Interpolation between adjustment points is linear.
+
+ The 'identification' string is used to identify the situation and/or
+ device where this adjustment should apply. The following is then
+ repeated for every adjustment point
+
+ Frequency $xx xx
+ Volume adjustment $xx xx
+
+ The frequency is stored in units of 1/2 Hz, giving it a range from 0
+ to 32767 Hz.
+
+ The volume adjustment is encoded as a fixed point decibel value, 16
+ bit signed integer representing (adjustment*512), giving +/- 64 dB
+ with a precision of 0.001953125 dB. E.g. +2 dB is stored as $04 00
+ and -2 dB is $FC 00.
+
+ Adjustment points should be ordered by frequency and one frequency
+ should only be described once in the frame.
+
+
+4.13. Reverb
+
+ Yet another subjective frame, with which you can adjust echoes of
+ different kinds. Reverb left/right is the delay between every bounce
+ in ms. Reverb bounces left/right is the number of bounces that should
+ be made. $FF equals an infinite number of bounces. Feedback is the
+ amount of volume that should be returned to the next echo bounce. $00
+ is 0%, $FF is 100%. If this value were $7F, there would be 50% volume
+ reduction on the first bounce, 50% of that on the second and so on.
+ Left to left means the sound from the left bounce to be played in the
+ left speaker, while left to right means sound from the left bounce to
+ be played in the right speaker.
+
+ 'Premix left to right' is the amount of left sound to be mixed in the
+ right before any reverb is applied, where $00 id 0% and $FF is 100%.
+ 'Premix right to left' does the same thing, but right to left.
+ Setting both premix to $FF would result in a mono output (if the
+ reverb is applied symmetric). There may only be one "RVRB" frame in
+ each tag.
+
+ <Header for 'Reverb', ID: "RVRB">
+ Reverb left (ms) $xx xx
+ Reverb right (ms) $xx xx
+ Reverb bounces, left $xx
+ Reverb bounces, right $xx
+ Reverb feedback, left to left $xx
+ Reverb feedback, left to right $xx
+ Reverb feedback, right to right $xx
+ Reverb feedback, right to left $xx
+ Premix left to right $xx
+ Premix right to left $xx
+
+
+4.14. Attached picture
+
+ This frame contains a picture directly related to the audio file.
+ Image format is the MIME type and subtype [MIME] for the image. In
+ the event that the MIME media type name is omitted, "image/" will be
+ implied. The "image/png" [PNG] or "image/jpeg" [JFIF] picture format
+ should be used when interoperability is wanted. Description is a
+ short description of the picture, represented as a terminated
+ text string. There may be several pictures attached to one file, each
+ in their individual "APIC" frame, but only one with the same content
+ descriptor. There may only be one picture with the picture type
+ declared as picture type $01 and $02 respectively. There is the
+ possibility to put only a link to the image file by using the 'MIME
+ type' "-->" and having a complete URL [URL] instead of picture data.
+ The use of linked files should however be used sparingly since there
+ is the risk of separation of files.
+
+ <Header for 'Attached picture', ID: "APIC">
+ Text encoding $xx
+ MIME type <text string> $00
+ Picture type $xx
+ Description <text string according to encoding> $00 (00)
+ Picture data <binary data>
+
+
+ Picture type: $00 Other
+ $01 32x32 pixels 'file icon' (PNG only)
+ $02 Other file icon
+ $03 Cover (front)
+ $04 Cover (back)
+ $05 Leaflet page
+ $06 Media (e.g. label side of CD)
+ $07 Lead artist/lead performer/soloist
+ $08 Artist/performer
+ $09 Conductor
+ $0A Band/Orchestra
+ $0B Composer
+ $0C Lyricist/text writer
+ $0D Recording Location
+ $0E During recording
+ $0F During performance
+ $10 Movie/video screen capture
+ $11 A bright coloured fish
+ $12 Illustration
+ $13 Band/artist logotype
+ $14 Publisher/Studio logotype
+
+
+4.15. General encapsulated object
+
+ In this frame any type of file can be encapsulated. After the header,
+ 'Frame size' and 'Encoding' follows 'MIME type' [MIME] represented as
+ as a terminated string encoded with ISO 8859-1 [ISO-8859-1]. The
+ filename is case sensitive and is encoded as 'Encoding'. Then follows
+ a content description as terminated string, encoded as 'Encoding'.
+ The last thing in the frame is the actual object. The first two
+ strings may be omitted, leaving only their terminations. MIME type is
+ always an ISO-8859-1 text string. There may be more than one "GEOB"
+ frame in each tag, but only one with the same content descriptor.
+
+ <Header for 'General encapsulated object', ID: "GEOB">
+ Text encoding $xx
+ MIME type <text string> $00
+ Filename <text string according to encoding> $00 (00)
+ Content description <text string according to encoding> $00 (00)
+ Encapsulated object <binary data>
+
+
+4.16. Play counter
+
+ This is simply a counter of the number of times a file has been
+ played. The value is increased by one every time the file begins to
+ play. There may only be one "PCNT" frame in each tag. When the
+ counter reaches all one's, one byte is inserted in front of the
+ counter thus making the counter eight bits bigger. The counter must
+ be at least 32-bits long to begin with.
+
+ <Header for 'Play counter', ID: "PCNT">
+ Counter $xx xx xx xx (xx ...)
+
+
+4.17. Popularimeter
+
+ The purpose of this frame is to specify how good an audio file is.
+ Many interesting applications could be found to this frame such as a
+ playlist that features better audio files more often than others or
+ it could be used to profile a person's taste and find other 'good'
+ files by comparing people's profiles. The frame contains the email
+ address to the user, one rating byte and a four byte play counter,
+ intended to be increased with one for every time the file is played.
+ The email is a terminated string. The rating is 1-255 where 1 is
+ worst and 255 is best. 0 is unknown. If no personal counter is wanted
+ it may be omitted. When the counter reaches all one's, one byte is
+ inserted in front of the counter thus making the counter eight bits
+ bigger in the same away as the play counter ("PCNT"). There may be
+ more than one "POPM" frame in each tag, but only one with the same
+ email address.
+
+ <Header for 'Popularimeter', ID: "POPM">
+ Email to user <text string> $00
+ Rating $xx
+ Counter $xx xx xx xx (xx ...)
+
+
+4.18. Recommended buffer size
+
+ Sometimes the server from which an audio file is streamed is aware of
+ transmission or coding problems resulting in interruptions in the
+ audio stream. In these cases, the size of the buffer can be
+ recommended by the server using this frame. If the 'embedded info
+ flag' is true (1) then this indicates that an ID3 tag with the
+ maximum size described in 'Buffer size' may occur in the audio
+ stream. In such case the tag should reside between two MPEG [MPEG]
+ frames, if the audio is MPEG encoded. If the position of the next tag
+ is known, 'offset to next tag' may be used. The offset is calculated
+ from the end of tag in which this frame resides to the first byte of
+ the header in the next. This field may be omitted. Embedded tags are
+ generally not recommended since this could render unpredictable
+ behaviour from present software/hardware.
+
+ For applications like streaming audio it might be an idea to embed
+ tags into the audio stream though. If the clients connects to
+ individual connections like HTTP and there is a possibility to begin
+ every transmission with a tag, then this tag should include a
+ 'recommended buffer size' frame. If the client is connected to a
+ arbitrary point in the stream, such as radio or multicast, then the
+ 'recommended buffer size' frame SHOULD be included in every tag.
+
+ The 'Buffer size' should be kept to a minimum. There may only be one
+ "RBUF" frame in each tag.
+
+ <Header for 'Recommended buffer size', ID: "RBUF">
+ Buffer size $xx xx xx
+ Embedded info flag %0000000x
+ Offset to next tag $xx xx xx xx
+
+
+4.19. Audio encryption
+
+ This frame indicates if the actual audio stream is encrypted, and by
+ whom. Since standardisation of such encryption scheme is beyond this
+ document, all "AENC" frames begin with a terminated string with a
+ URL containing an email address, or a link to a location where an
+ email address can be found, that belongs to the organisation
+ responsible for this specific encrypted audio file. Questions
+ regarding the encrypted audio should be sent to the email address
+ specified. If a $00 is found directly after the 'Frame size' and the
+ audio file indeed is encrypted, the whole file may be considered
+ useless.
+
+ After the 'Owner identifier', a pointer to an unencrypted part of the
+ audio can be specified. The 'Preview start' and 'Preview length' is
+ described in frames. If no part is unencrypted, these fields should
+ be left zeroed. After the 'preview length' field follows optionally a
+ data block required for decryption of the audio. There may be more
+ than one "AENC" frames in a tag, but only one with the same 'Owner
+ identifier'.
+
+ <Header for 'Audio encryption', ID: "AENC">
+ Owner identifier <text string> $00
+ Preview start $xx xx
+ Preview length $xx xx
+ Encryption info <binary data>
+
+
+4.20. Linked information
+
+ To keep information duplication as low as possible this frame may be
+ used to link information from another ID3v2 tag that might reside in
+ another audio file or alone in a binary file. It is RECOMMENDED that
+ this method is only used when the files are stored on a CD-ROM or
+ other circumstances when the risk of file separation is low. The
+ frame contains a frame identifier, which is the frame that should be
+ linked into this tag, a URL [URL] field, where a reference to the
+ file where the frame is given, and additional ID data, if needed.
+ Data should be retrieved from the first tag found in the file to
+ which this link points. There may be more than one "LINK" frame in a
+ tag, but only one with the same contents. A linked frame is to be
+ considered as part of the tag and has the same restrictions as if it
+ was a physical part of the tag (i.e. only one "RVRB" frame allowed,
+ whether it's linked or not).
+
+ <Header for 'Linked information', ID: "LINK">
+ Frame identifier $xx xx xx xx
+ URL <text string> $00
+ ID and additional data <text string(s)>
+
+ Frames that may be linked and need no additional data are "ASPI",
+ "ETCO", "EQU2", "MCID", "MLLT", "OWNE", "RVA2", "RVRB", "SYTC", the
+ text information frames and the URL link frames.
+
+ The "AENC", "APIC", "GEOB" and "TXXX" frames may be linked with
+ the content descriptor as additional ID data.
+
+ The "USER" frame may be linked with the language field as additional
+ ID data.
+
+ The "PRIV" frame may be linked with the owner identifier as
+ additional ID data.
+
+ The "COMM", "SYLT" and "USLT" frames may be linked with three bytes
+ of language descriptor directly followed by a content descriptor as
+ additional ID data.
+
+
+4.21. Position synchronisation frame
+
+ This frame delivers information to the listener of how far into the
+ audio stream he picked up; in effect, it states the time offset from
+ the first frame in the stream. The frame layout is:
+
+ <Head for 'Position synchronisation', ID: "POSS">
+ Time stamp format $xx
+ Position $xx (xx ...)
+
+ Where time stamp format is:
+
+ $01 Absolute time, 32 bit sized, using MPEG frames as unit
+ $02 Absolute time, 32 bit sized, using milliseconds as unit
+
+ and position is where in the audio the listener starts to receive,
+ i.e. the beginning of the next frame. If this frame is used in the
+ beginning of a file the value is always 0. There may only be one
+ "POSS" frame in each tag.
+
+
+4.22. Terms of use frame
+
+ This frame contains a brief description of the terms of use and
+ ownership of the file. More detailed information concerning the legal
+ terms might be available through the "WCOP" frame. Newlines are
+ allowed in the text. There may be more than one 'Terms of use' frame
+ in a tag, but only one with the same 'Language'.
+
+ <Header for 'Terms of use frame', ID: "USER">
+ Text encoding $xx
+ Language $xx xx xx
+ The actual text <text string according to encoding>
+
+
+4.23. Ownership frame
+
+ The ownership frame might be used as a reminder of a made transaction
+ or, if signed, as proof. Note that the "USER" and "TOWN" frames are
+ good to use in conjunction with this one. The frame begins, after the
+ frame ID, size and encoding fields, with a 'price paid' field. The
+ first three characters of this field contains the currency used for
+ the transaction, encoded according to ISO 4217 [ISO-4217] alphabetic
+ currency code. Concatenated to this is the actual price paid, as a
+ numerical string using "." as the decimal separator. Next is an 8
+ character date string (YYYYMMDD) followed by a string with the name
+ of the seller as the last field in the frame. There may only be one
+ "OWNE" frame in a tag.
+
+ <Header for 'Ownership frame', ID: "OWNE">
+ Text encoding $xx
+ Price paid <text string> $00
+ Date of purch. <text string>
+ Seller <text string according to encoding>
+
+
+4.24. Commercial frame
+
+ This frame enables several competing offers in the same tag by
+ bundling all needed information. That makes this frame rather complex
+ but it's an easier solution than if one tries to achieve the same
+ result with several frames. The frame begins, after the frame ID,
+ size and encoding fields, with a price string field. A price is
+ constructed by one three character currency code, encoded according
+ to ISO 4217 [ISO-4217] alphabetic currency code, followed by a
+ numerical value where "." is used as decimal separator. In the price
+ string several prices may be concatenated, separated by a "/"
+ character, but there may only be one currency of each type.
+
+ The price string is followed by an 8 character date string in the
+ format YYYYMMDD, describing for how long the price is valid. After
+ that is a contact URL, with which the user can contact the seller,
+ followed by a one byte 'received as' field. It describes how the
+ audio is delivered when bought according to the following list:
+
+ $00 Other
+ $01 Standard CD album with other songs
+ $02 Compressed audio on CD
+ $03 File over the Internet
+ $04 Stream over the Internet
+ $05 As note sheets
+ $06 As note sheets in a book with other sheets
+ $07 Music on other media
+ $08 Non-musical merchandise
+
+ Next follows a terminated string with the name of the seller followed
+ by a terminated string with a short description of the product. The
+ last thing is the ability to include a company logotype. The first of
+ them is the 'Picture MIME type' field containing information about
+ which picture format is used. In the event that the MIME media type
+ name is omitted, "image/" will be implied. Currently only "image/png"
+ and "image/jpeg" are allowed. This format string is followed by the
+ binary picture data. This two last fields may be omitted if no
+ picture is attached. There may be more than one 'commercial frame' in
+ a tag, but no two may be identical.
+
+ <Header for 'Commercial frame', ID: "COMR">
+ Text encoding $xx
+ Price string <text string> $00
+ Valid until <text string>
+ Contact URL <text string> $00
+ Received as $xx
+ Name of seller <text string according to encoding> $00 (00)
+ Description <text string according to encoding> $00 (00)
+ Picture MIME type <string> $00
+ Seller logo <binary data>
+
+
+4.25. Encryption method registration
+
+ To identify with which method a frame has been encrypted the
+ encryption method must be registered in the tag with this frame. The
+ 'Owner identifier' is a null-terminated string with a URL [URL]
+ containing an email address, or a link to a location where an email
+ address can be found, that belongs to the organisation responsible
+ for this specific encryption method. Questions regarding the
+ encryption method should be sent to the indicated email address. The
+ 'Method symbol' contains a value that is associated with this method
+ throughout the whole tag, in the range $80-F0. All other values are
+ reserved. The 'Method symbol' may optionally be followed by
+ encryption specific data. There may be several "ENCR" frames in a tag
+ but only one containing the same symbol and only one containing the
+ same owner identifier. The method must be used somewhere in the tag.
+ See the description of the frame encryption flag in the ID3v2
+ structure document [ID3v2-strct] for more information.
+
+ <Header for 'Encryption method registration', ID: "ENCR">
+ Owner identifier <text string> $00
+ Method symbol $xx
+ Encryption data <binary data>
+
+
+4.26. Group identification registration
+
+ This frame enables grouping of otherwise unrelated frames. This can
+ be used when some frames are to be signed. To identify which frames
+ belongs to a set of frames a group identifier must be registered in
+ the tag with this frame. The 'Owner identifier' is a null-terminated
+ string with a URL [URL] containing an email address, or a link to a
+ location where an email address can be found, that belongs to the
+ organisation responsible for this grouping. Questions regarding the
+ grouping should be sent to the indicated email address. The 'Group
+ symbol' contains a value that associates the frame with this group
+ throughout the whole tag, in the range $80-F0. All other values are
+ reserved. The 'Group symbol' may optionally be followed by some group
+ specific data, e.g. a digital signature. There may be several "GRID"
+ frames in a tag but only one containing the same symbol and only one
+ containing the same owner identifier. The group symbol must be used
+ somewhere in the tag. See the description of the frame grouping flag
+ in the ID3v2 structure document [ID3v2-strct] for more information.
+
+ <Header for 'Group ID registration', ID: "GRID">
+ Owner identifier <text string> $00
+ Group symbol $xx
+ Group dependent data <binary data>
+
+
+4.27. Private frame
+
+ This frame is used to contain information from a software producer
+ that its program uses and does not fit into the other frames. The
+ frame consists of an 'Owner identifier' string and the binary data.
+ The 'Owner identifier' is a null-terminated string with a URL [URL]
+ containing an email address, or a link to a location where an email
+ address can be found, that belongs to the organisation responsible
+ for the frame. Questions regarding the frame should be sent to the
+ indicated email address. The tag may contain more than one "PRIV"
+ frame but only with different contents.
+
+ <Header for 'Private frame', ID: "PRIV">
+ Owner identifier <text string> $00
+ The private data <binary data>
+
+
+4.28. Signature frame
+
+ This frame enables a group of frames, grouped with the 'Group
+ identification registration', to be signed. Although signatures can
+ reside inside the registration frame, it might be desired to store
+ the signature elsewhere, e.g. in watermarks. There may be more than
+ one 'signature frame' in a tag, but no two may be identical.
+
+ <Header for 'Signature frame', ID: "SIGN">
+ Group symbol $xx
+ Signature <binary data>
+
+
+4.29. Seek frame
+
+ This frame indicates where other tags in a file/stream can be found.
+ The 'minimum offset to next tag' is calculated from the end of this
+ tag to the beginning of the next. There may only be one 'seek frame'
+ in a tag.
+
+ <Header for 'Seek frame', ID: "SEEK">
+ Minimum offset to next tag $xx xx xx xx
+
+
+4.30. Audio seek point index
+
+ Audio files with variable bit rates are intrinsically difficult to
+ deal with in the case of seeking within the file. The ASPI frame
+ makes seeking easier by providing a list a seek points within the
+ audio file. The seek points are a fractional offset within the audio
+ data, providing a starting point from which to find an appropriate
+ point to start decoding. The presence of an ASPI frame requires the
+ existence of a TLEN frame, indicating the duration of the file in
+ milliseconds. There may only be one 'audio seek point index' frame in
+ a tag.
+
+ <Header for 'Seek Point Index', ID: "ASPI">
+ Indexed data start (S) $xx xx xx xx
+ Indexed data length (L) $xx xx xx xx
+ Number of index points (N) $xx xx
+ Bits per index point (b) $xx
+
+ Then for every index point the following data is included;
+
+ Fraction at index (Fi) $xx (xx)
+
+ 'Indexed data start' is a byte offset from the beginning of the file.
+ 'Indexed data length' is the byte length of the audio data being
+ indexed. 'Number of index points' is the number of index points, as
+ the name implies. The recommended number is 100. 'Bits per index
+ point' is 8 or 16, depending on the chosen precision. 8 bits works
+ well for short files (less than 5 minutes of audio), while 16 bits is
+ advantageous for long files. 'Fraction at index' is the numerator of
+ the fraction representing a relative position in the data. The
+ denominator is 2 to the power of b.
+
+ Here are the algorithms to be used in the calculation. The known data
+ must be the offset of the start of the indexed data (S), the offset
+ of the end of the indexed data (E), the number of index points (N),
+ the offset at index i (Oi). We calculate the fraction at index i
+ (Fi).
+
+ Oi is the offset of the frame whose start is soonest after the point
+ for which the time offset is (i/N * duration).
+
+ The frame data should be calculated as follows:
+
+ Fi = Oi/L * 2^b (rounded down to the nearest integer)
+
+ Offset calculation should be calculated as follows from data in the
+ frame:
+
+ Oi = (Fi/2^b)*L (rounded up to the nearest integer)
+
+
+5. Copyright
+
+ Copyright (C) Martin Nilsson 2000. All Rights Reserved.
+
+ This document and translations of it may be copied and furnished to
+ others, and derivative works that comment on or otherwise explain it
+ or assist in its implementation may be prepared, copied, published
+ and distributed, in whole or in part, without restriction of any
+ kind, provided that a reference to this document is included on all
+ such copies and derivative works. However, this document itself may
+ not be modified in any way and reissued as the original document.
+
+ The limited permissions granted above are perpetual and will not be
+ revoked.
+
+ This document and the information contained herein is provided on an
+ "AS IS" basis and THE AUTHORS DISCLAIMS ALL WARRANTIES, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
+ THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+ WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+
+6. References
+
+ [CDDB] Compact Disc Data Base
+
+ <url:http://www.cddb.com>
+
+ [ID3v2.3.0] Martin Nilsson, "ID3v2 informal standard".
+
+ <url:http://www.id3.org/id3v2.3.0.txt>
+
+ [ID3v2-strct] Martin Nilsson,
+ "ID3 tag version 2.4.0 - Main Structure"
+
+ <url:http//www.id3.org/id3v2.4.0-structure.txt>
+
+ [ISO-639-2] ISO/FDIS 639-2.
+ Codes for the representation of names of languages, Part 2: Alpha-3
+ code. Technical committee / subcommittee: TC 37 / SC 2
+
+ [ISO-4217] ISO 4217:1995.
+ Codes for the representation of currencies and funds.
+ Technical committee / subcommittee: TC 68
+
+ [ISO-8859-1] ISO/IEC DIS 8859-1.
+ 8-bit single-byte coded graphic character sets, Part 1: Latin
+ alphabet No. 1. Technical committee / subcommittee: JTC 1 / SC 2
+
+ [ISRC] ISO 3901:1986
+ International Standard Recording Code (ISRC).
+ Technical committee / subcommittee: TC 46 / SC 9
+
+ [JFIF] JPEG File Interchange Format, version 1.02
+
+ <url:http://www.w3.org/Graphics/JPEG/jfif.txt>
+
+ [KEYWORDS] S. Bradner, 'Key words for use in RFCs to Indicate
+ Requirement Levels', RFC 2119, March 1997.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc2119.txt>
+
+ [MIME] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
+ Extensions (MIME) Part One: Format of Internet Message Bodies",
+ RFC 2045, November 1996.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc2045.txt>
+
+ [MPEG] ISO/IEC 11172-3:1993.
+ Coding of moving pictures and associated audio for digital storage
+ media at up to about 1,5 Mbit/s, Part 3: Audio.
+ Technical committee / subcommittee: JTC 1 / SC 29
+ and
+ ISO/IEC 13818-3:1995
+ Generic coding of moving pictures and associated audio information,
+ Part 3: Audio.
+ Technical committee / subcommittee: JTC 1 / SC 29
+ and
+ ISO/IEC DIS 13818-3
+ Generic coding of moving pictures and associated audio information,
+ Part 3: Audio (Revision of ISO/IEC 13818-3:1995)
+
+
+ [PNG] Portable Network Graphics, version 1.0
+
+ <url:http://www.w3.org/TR/REC-png-multi.html>
+
+ [URL] T. Berners-Lee, L. Masinter & M. McCahill, "Uniform Resource
+ Locators (URL).", RFC 1738, December 1994.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc1738.txt>
+
+ [ZLIB] P. Deutsch, Aladdin Enterprises & J-L. Gailly, "ZLIB
+ Compressed
+ Data Format Specification version 3.3", RFC 1950, May 1996.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc1950.txt>
+
+
+7. Appendix
+
+
+A. Appendix A - Genre List from ID3v1
+
+ The following genres is defined in ID3v1
+
+ 0.Blues
+ 1.Classic Rock
+ 2.Country
+ 3.Dance
+ 4.Disco
+ 5.Funk
+ 6.Grunge
+ 7.Hip-Hop
+ 8.Jazz
+ 9.Metal
+ 10.New Age
+ 11.Oldies
+ 12.Other
+ 13.Pop
+ 14.R&B
+ 15.Rap
+ 16.Reggae
+ 17.Rock
+ 18.Techno
+ 19.Industrial
+ 20.Alternative
+ 21.Ska
+ 22.Death Metal
+ 23.Pranks
+ 24.Soundtrack
+ 25.Euro-Techno
+ 26.Ambient
+ 27.Trip-Hop
+ 28.Vocal
+ 29.Jazz+Funk
+ 30.Fusion
+ 31.Trance
+ 32.Classical
+ 33.Instrumental
+ 34.Acid
+ 35.House
+ 36.Game
+ 37.Sound Clip
+ 38.Gospel
+ 39.Noise
+ 40.AlternRock
+ 41.Bass
+ 42.Soul
+ 43.Punk
+ 44.Space
+ 45.Meditative
+ 46.Instrumental Pop
+ 47.Instrumental Rock
+ 48.Ethnic
+ 49.Gothic
+ 50.Darkwave
+ 51.Techno-Industrial
+ 52.Electronic
+ 53.Pop-Folk
+ 54.Eurodance
+ 55.Dream
+ 56.Southern Rock
+ 57.Comedy
+ 58.Cult
+ 59.Gangsta
+ 60.Top 40
+ 61.Christian Rap
+ 62.Pop/Funk
+ 63.Jungle
+ 64.Native American
+ 65.Cabaret
+ 66.New Wave
+ 67.Psychadelic
+ 68.Rave
+ 69.Showtunes
+ 70.Trailer
+ 71.Lo-Fi
+ 72.Tribal
+ 73.Acid Punk
+ 74.Acid Jazz
+ 75.Polka
+ 76.Retro
+ 77.Musical
+ 78.Rock & Roll
+ 79.Hard Rock
+
+
+8. Author's Address
+
+ Written by
+
+ Martin Nilsson
+ Rydsvägen 246 C. 30
+ SE-584 34 Linköping
+ Sweden
+
+ Email: nilsson@id3.org
--- /dev/null
+
+Informal standard M. Nilsson
+Document: id3v2.4.0-structure.txt 16 September 2001
+
+
+ ID3 tag version 2.4.0 - Main Structure
+
+Status of this document
+
+ This document is an informal standard and replaces the ID3v2.3.0
+ standard [ID3v2]. A formal standard will use another revision number
+ even if the content is identical to document. The contents in this
+ document may change for clarifications but never for added or altered
+ functionallity.
+
+ Distribution of this document is unlimited.
+
+
+Abstract
+
+ This document describes the main structure of ID3v2.4.0, which is a
+ revised version of the ID3v2 informal standard [ID3v2] version
+ 2.3.0. The ID3v2 offers a flexible way of storing audio meta
+ information within the audio file itself. The information may be
+ technical information, such as equalisation curves, as well as
+ title, performer, copyright etc.
+
+ ID3v2.4.0 is meant to be as close as possible to ID3v2.3.0 in order
+ to allow for implementations to be revised as easily as possible.
+
+
+1. Table of contents
+
+ Status of this document
+ Abstract
+ 1. Table of contents
+ 2. Conventions in this document
+ 2. Standard overview
+ 3. ID3v2 overview
+ 3.1. ID3v2 header
+ 3.2. ID3v2 extended header
+ 3.3. Padding
+ 3.4. ID3v2 footer
+ 4. ID3v2 frames overview
+ 4.1. Frame header flags
+ 4.1.1. Frame status flags
+ 4.1.2. Frame format flags
+ 5. Tag location
+ 6. Unsynchronisation
+ 6.1. The unsynchronisation scheme
+ 6.2. Synchsafe integers
+ 7. Copyright
+ 8. References
+ 9. Author's Address
+
+
+2. Conventions in this document
+
+ Text within "" is a text string exactly as it appears in a tag.
+ Numbers preceded with $ are hexadecimal and numbers preceded with %
+ are binary. $xx is used to indicate a byte with unknown content. %x
+ is used to indicate a bit with unknown content. The most significant
+ bit (MSB) of a byte is called 'bit 7' and the least significant bit
+ (LSB) is called 'bit 0'.
+
+ A tag is the whole tag described in this document. A frame is a block
+ of information in the tag. The tag consists of a header, frames and
+ optional padding. A field is a piece of information; one value, a
+ string etc. A numeric string is a string that consists of the
+ characters "0123456789" only.
+
+ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+ "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+ document are to be interpreted as described in RFC 2119 [KEYWORDS].
+
+
+3. ID3v2 overview
+
+ ID3v2 is a general tagging format for audio, which makes it possible
+ to store meta data about the audio inside the audio file itself. The
+ ID3 tag described in this document is mainly targeted at files
+ encoded with MPEG-1/2 layer I, MPEG-1/2 layer II, MPEG-1/2 layer III
+ and MPEG-2.5, but may work with other types of encoded audio or as a
+ stand alone format for audio meta data.
+
+ ID3v2 is designed to be as flexible and expandable as possible to
+ meet new meta information needs that might arise. To achieve that
+ ID3v2 is constructed as a container for several information blocks,
+ called frames, whose format need not be known to the software that
+ encounters them. At the start of every frame is an unique and
+ predefined identifier, a size descriptor that allows software to skip
+ unknown frames and a flags field. The flags describes encoding
+ details and if the frame should remain in the tag, should it be
+ unknown to the software, if the file is altered.
+
+ The bitorder in ID3v2 is most significant bit first (MSB). The
+ byteorder in multibyte numbers is most significant byte first (e.g.
+ $12345678 would be encoded $12 34 56 78), also known as big endian
+ and network byte order.
+
+ Overall tag structure:
+
+ +-----------------------------+
+ | Header (10 bytes) |
+ +-----------------------------+
+ | Extended Header |
+ | (variable length, OPTIONAL) |
+ +-----------------------------+
+ | Frames (variable length) |
+ +-----------------------------+
+ | Padding |
+ | (variable length, OPTIONAL) |
+ +-----------------------------+
+ | Footer (10 bytes, OPTIONAL) |
+ +-----------------------------+
+
+ In general, padding and footer are mutually exclusive. See details in
+ sections 3.3, 3.4 and 5.
+
+
+3.1. ID3v2 header
+
+ The first part of the ID3v2 tag is the 10 byte tag header, laid out
+ as follows:
+
+ ID3v2/file identifier "ID3"
+ ID3v2 version $04 00
+ ID3v2 flags %abcd0000
+ ID3v2 size 4 * %0xxxxxxx
+
+ The first three bytes of the tag are always "ID3", to indicate that
+ this is an ID3v2 tag, directly followed by the two version bytes. The
+ first byte of ID3v2 version is its major version, while the second
+ byte is its revision number. In this case this is ID3v2.4.0. All
+ revisions are backwards compatible while major versions are not. If
+ software with ID3v2.4.0 and below support should encounter version
+ five or higher it should simply ignore the whole tag. Version or
+ revision will never be $FF.
+
+ The version is followed by the ID3v2 flags field, of which currently
+ four flags are used.
+
+
+ a - Unsynchronisation
+
+ Bit 7 in the 'ID3v2 flags' indicates whether or not
+ unsynchronisation is applied on all frames (see section 6.1 for
+ details); a set bit indicates usage.
+
+
+ b - Extended header
+
+ The second bit (bit 6) indicates whether or not the header is
+ followed by an extended header. The extended header is described in
+ section 3.2. A set bit indicates the presence of an extended
+ header.
+
+
+ c - Experimental indicator
+
+ The third bit (bit 5) is used as an 'experimental indicator'. This
+ flag SHALL always be set when the tag is in an experimental stage.
+
+
+ d - Footer present
+
+ Bit 4 indicates that a footer (section 3.4) is present at the very
+ end of the tag. A set bit indicates the presence of a footer.
+
+
+ All the other flags MUST be cleared. If one of these undefined flags
+ are set, the tag might not be readable for a parser that does not
+ know the flags function.
+
+ The ID3v2 tag size is stored as a 32 bit synchsafe integer (section
+ 6.2), making a total of 28 effective bits (representing up to 256MB).
+
+ The ID3v2 tag size is the sum of the byte length of the extended
+ header, the padding and the frames after unsynchronisation. If a
+ footer is present this equals to ('total size' - 20) bytes, otherwise
+ ('total size' - 10) bytes.
+
+ An ID3v2 tag can be detected with the following pattern:
+ $49 44 33 yy yy xx zz zz zz zz
+ Where yy is less than $FF, xx is the 'flags' byte and zz is less than
+ $80.
+
+
+3.2. Extended header
+
+ The extended header contains information that can provide further
+ insight in the structure of the tag, but is not vital to the correct
+ parsing of the tag information; hence the extended header is
+ optional.
+
+ Extended header size 4 * %0xxxxxxx
+ Number of flag bytes $01
+ Extended Flags $xx
+
+ Where the 'Extended header size' is the size of the whole extended
+ header, stored as a 32 bit synchsafe integer. An extended header can
+ thus never have a size of fewer than six bytes.
+
+ The extended flags field, with its size described by 'number of flag
+ bytes', is defined as:
+
+ %0bcd0000
+
+ Each flag that is set in the extended header has data attached, which
+ comes in the order in which the flags are encountered (i.e. the data
+ for flag 'b' comes before the data for flag 'c'). Unset flags cannot
+ have any attached data. All unknown flags MUST be unset and their
+ corresponding data removed when a tag is modified.
+
+ Every set flag's data starts with a length byte, which contains a
+ value between 0 and 127 ($00 - $7f), followed by data that has the
+ field length indicated by the length byte. If a flag has no attached
+ data, the value $00 is used as length byte.
+
+
+ b - Tag is an update
+
+ If this flag is set, the present tag is an update of a tag found
+ earlier in the present file or stream. If frames defined as unique
+ are found in the present tag, they are to override any
+ corresponding ones found in the earlier tag. This flag has no
+ corresponding data.
+
+ Flag data length $00
+
+ c - CRC data present
+
+ If this flag is set, a CRC-32 [ISO-3309] data is included in the
+ extended header. The CRC is calculated on all the data between the
+ header and footer as indicated by the header's tag length field,
+ minus the extended header. Note that this includes the padding (if
+ there is any), but excludes the footer. The CRC-32 is stored as an
+ 35 bit synchsafe integer, leaving the upper four bits always
+ zeroed.
+
+ Flag data length $05
+ Total frame CRC 5 * %0xxxxxxx
+
+ d - Tag restrictions
+
+ For some applications it might be desired to restrict a tag in more
+ ways than imposed by the ID3v2 specification. Note that the
+ presence of these restrictions does not affect how the tag is
+ decoded, merely how it was restricted before encoding. If this flag
+ is set the tag is restricted as follows:
+
+ Flag data length $01
+ Restrictions %ppqrrstt
+
+ p - Tag size restrictions
+
+ 00 No more than 128 frames and 1 MB total tag size.
+ 01 No more than 64 frames and 128 KB total tag size.
+ 10 No more than 32 frames and 40 KB total tag size.
+ 11 No more than 32 frames and 4 KB total tag size.
+
+ q - Text encoding restrictions
+
+ 0 No restrictions
+ 1 Strings are only encoded with ISO-8859-1 [ISO-8859-1] or
+ UTF-8 [UTF-8].
+
+ r - Text fields size restrictions
+
+ 00 No restrictions
+ 01 No string is longer than 1024 characters.
+ 10 No string is longer than 128 characters.
+ 11 No string is longer than 30 characters.
+
+ Note that nothing is said about how many bytes is used to
+ represent those characters, since it is encoding dependent. If a
+ text frame consists of more than one string, the sum of the
+ strungs is restricted as stated.
+
+ s - Image encoding restrictions
+
+ 0 No restrictions
+ 1 Images are encoded only with PNG [PNG] or JPEG [JFIF].
+
+ t - Image size restrictions
+
+ 00 No restrictions
+ 01 All images are 256x256 pixels or smaller.
+ 10 All images are 64x64 pixels or smaller.
+ 11 All images are exactly 64x64 pixels, unless required
+ otherwise.
+
+
+3.3. Padding
+
+ It is OPTIONAL to include padding after the final frame (at the end
+ of the ID3 tag), making the size of all the frames together smaller
+ than the size given in the tag header. A possible purpose of this
+ padding is to allow for adding a few additional frames or enlarge
+ existing frames within the tag without having to rewrite the entire
+ file. The value of the padding bytes must be $00. A tag MUST NOT have
+ any padding between the frames or between the tag header and the
+ frames. Furthermore it MUST NOT have any padding when a tag footer is
+ added to the tag.
+
+
+3.4. ID3v2 footer
+
+ To speed up the process of locating an ID3v2 tag when searching from
+ the end of a file, a footer can be added to the tag. It is REQUIRED
+ to add a footer to an appended tag, i.e. a tag located after all
+ audio data. The footer is a copy of the header, but with a different
+ identifier.
+
+ ID3v2 identifier "3DI"
+ ID3v2 version $04 00
+ ID3v2 flags %abcd0000
+ ID3v2 size 4 * %0xxxxxxx
+
+
+4. ID3v2 frame overview
+
+ All ID3v2 frames consists of one frame header followed by one or more
+ fields containing the actual information. The header is always 10
+ bytes and laid out as follows:
+
+ Frame ID $xx xx xx xx (four characters)
+ Size 4 * %0xxxxxxx
+ Flags $xx xx
+
+ The frame ID is made out of the characters capital A-Z and 0-9.
+ Identifiers beginning with "X", "Y" and "Z" are for experimental
+ frames and free for everyone to use, without the need to set the
+ experimental bit in the tag header. Bear in mind that someone else
+ might have used the same identifier as you. All other identifiers are
+ either used or reserved for future use.
+
+ The frame ID is followed by a size descriptor containing the size of
+ the data in the final frame, after encryption, compression and
+ unsynchronisation. The size is excluding the frame header ('total
+ frame size' - 10 bytes) and stored as a 32 bit synchsafe integer.
+
+ In the frame header the size descriptor is followed by two flag
+ bytes. These flags are described in section 4.1.
+
+ There is no fixed order of the frames' appearance in the tag,
+ although it is desired that the frames are arranged in order of
+ significance concerning the recognition of the file. An example of
+ such order: UFID, TIT2, MCDI, TRCK ...
+
+ A tag MUST contain at least one frame. A frame must be at least 1
+ byte big, excluding the header.
+
+ If nothing else is said, strings, including numeric strings and URLs
+ [URL], are represented as ISO-8859-1 [ISO-8859-1] characters in the
+ range $20 - $FF. Such strings are represented in frame descriptions
+ as <text string>, or <full text string> if newlines are allowed. If
+ nothing else is said newline character is forbidden. In ISO-8859-1 a
+ newline is represented, when allowed, with $0A only.
+
+ Frames that allow different types of text encoding contains a text
+ encoding description byte. Possible encodings:
+
+ $00 ISO-8859-1 [ISO-8859-1]. Terminated with $00.
+ $01 UTF-16 [UTF-16] encoded Unicode [UNICODE] with BOM. All
+ strings in the same frame SHALL have the same byteorder.
+ Terminated with $00 00.
+ $02 UTF-16BE [UTF-16] encoded Unicode [UNICODE] without BOM.
+ Terminated with $00 00.
+ $03 UTF-8 [UTF-8] encoded Unicode [UNICODE]. Terminated with $00.
+
+ Strings dependent on encoding are represented in frame descriptions
+ as <text string according to encoding>, or <full text string
+ according to encoding> if newlines are allowed. Any empty strings of
+ type $01 which are NULL-terminated may have the Unicode BOM followed
+ by a Unicode NULL ($FF FE 00 00 or $FE FF 00 00).
+
+ The timestamp fields are based on a subset of ISO 8601. When being as
+ precise as possible the format of a time string is
+ yyyy-MM-ddTHH:mm:ss (year, "-", month, "-", day, "T", hour (out of
+ 24), ":", minutes, ":", seconds), but the precision may be reduced by
+ removing as many time indicators as wanted. Hence valid timestamps
+ are
+ yyyy, yyyy-MM, yyyy-MM-dd, yyyy-MM-ddTHH, yyyy-MM-ddTHH:mm and
+ yyyy-MM-ddTHH:mm:ss. All time stamps are UTC. For durations, use
+ the slash character as described in 8601, and for multiple non-
+ contiguous dates, use multiple strings, if allowed by the frame
+ definition.
+
+ The three byte language field, present in several frames, is used to
+ describe the language of the frame's content, according to ISO-639-2
+ [ISO-639-2]. The language should be represented in lower case. If the
+ language is not known the string "XXX" should be used.
+
+ All URLs [URL] MAY be relative, e.g. "picture.png", "../doc.txt".
+
+ If a frame is longer than it should be, e.g. having more fields than
+ specified in this document, that indicates that additions to the
+ frame have been made in a later version of the ID3v2 standard. This
+ is reflected by the revision number in the header of the tag.
+
+
+4.1. Frame header flags
+
+ In the frame header the size descriptor is followed by two flag
+ bytes. All unused flags MUST be cleared. The first byte is for
+ 'status messages' and the second byte is a format description. If an
+ unknown flag is set in the first byte the frame MUST NOT be changed
+ without that bit cleared. If an unknown flag is set in the second
+ byte the frame is likely to not be readable. Some flags in the second
+ byte indicates that extra information is added to the header. These
+ fields of extra information is ordered as the flags that indicates
+ them. The flags field is defined as follows (l and o left out because
+ ther resemblence to one and zero):
+
+ %0abc0000 %0h00kmnp
+
+ Some frame format flags indicate that additional information fields
+ are added to the frame. This information is added after the frame
+ header and before the frame data in the same order as the flags that
+ indicates them. I.e. the four bytes of decompressed size will precede
+ the encryption method byte. These additions affects the 'frame size'
+ field, but are not subject to encryption or compression.
+
+ The default status flags setting for a frame is, unless stated
+ otherwise, 'preserved if tag is altered' and 'preserved if file is
+ altered', i.e. %00000000.
+
+
+4.1.1. Frame status flags
+
+ a - Tag alter preservation
+
+ This flag tells the tag parser what to do with this frame if it is
+ unknown and the tag is altered in any way. This applies to all
+ kinds of alterations, including adding more padding and reordering
+ the frames.
+
+ 0 Frame should be preserved.
+ 1 Frame should be discarded.
+
+
+ b - File alter preservation
+
+ This flag tells the tag parser what to do with this frame if it is
+ unknown and the file, excluding the tag, is altered. This does not
+ apply when the audio is completely replaced with other audio data.
+
+ 0 Frame should be preserved.
+ 1 Frame should be discarded.
+
+
+ c - Read only
+
+ This flag, if set, tells the software that the contents of this
+ frame are intended to be read only. Changing the contents might
+ break something, e.g. a signature. If the contents are changed,
+ without knowledge of why the frame was flagged read only and
+ without taking the proper means to compensate, e.g. recalculating
+ the signature, the bit MUST be cleared.
+
+
+4.1.2. Frame format flags
+
+ h - Grouping identity
+
+ This flag indicates whether or not this frame belongs in a group
+ with other frames. If set, a group identifier byte is added to the
+ frame. Every frame with the same group identifier belongs to the
+ same group.
+
+ 0 Frame does not contain group information
+ 1 Frame contains group information
+
+
+ k - Compression
+
+ This flag indicates whether or not the frame is compressed.
+ A 'Data Length Indicator' byte MUST be included in the frame.
+
+ 0 Frame is not compressed.
+ 1 Frame is compressed using zlib [zlib] deflate method.
+ If set, this requires the 'Data Length Indicator' bit
+ to be set as well.
+
+
+ m - Encryption
+
+ This flag indicates whether or not the frame is encrypted. If set,
+ one byte indicating with which method it was encrypted will be
+ added to the frame. See description of the ENCR frame for more
+ information about encryption method registration. Encryption
+ should be done after compression. Whether or not setting this flag
+ requires the presence of a 'Data Length Indicator' depends on the
+ specific algorithm used.
+
+ 0 Frame is not encrypted.
+ 1 Frame is encrypted.
+
+ n - Unsynchronisation
+
+ This flag indicates whether or not unsynchronisation was applied
+ to this frame. See section 6 for details on unsynchronisation.
+ If this flag is set all data from the end of this header to the
+ end of this frame has been unsynchronised. Although desirable, the
+ presence of a 'Data Length Indicator' is not made mandatory by
+ unsynchronisation.
+
+ 0 Frame has not been unsynchronised.
+ 1 Frame has been unsyrchronised.
+
+ p - Data length indicator
+
+ This flag indicates that a data length indicator has been added to
+ the frame. The data length indicator is the value one would write
+ as the 'Frame length' if all of the frame format flags were
+ zeroed, represented as a 32 bit synchsafe integer.
+
+ 0 There is no Data Length Indicator.
+ 1 A data length Indicator has been added to the frame.
+
+
+5. Tag location
+
+ The default location of an ID3v2 tag is prepended to the audio so
+ that players can benefit from the information when the data is
+ streamed. It is however possible to append the tag, or make a
+ prepend/append combination. When deciding upon where an unembedded
+ tag should be located, the following order of preference SHOULD be
+ considered.
+
+ 1. Prepend the tag.
+
+ 2. Prepend a tag with all vital information and add a second tag at
+ the end of the file, before tags from other tagging systems. The
+ first tag is required to have a SEEK frame.
+
+ 3. Add a tag at the end of the file, before tags from other tagging
+ systems.
+
+ In case 2 and 3 the tag can simply be appended if no other known tags
+ are present. The suggested method to find ID3v2 tags are:
+
+ 1. Look for a prepended tag using the pattern found in section 3.1.
+
+ 2. If a SEEK frame was found, use its values to guide further
+ searching.
+
+ 3. Look for a tag footer, scanning from the back of the file.
+
+ For every new tag that is found, the old tag should be discarded
+ unless the update flag in the extended header (section 3.2) is set.
+
+
+6. Unsynchronisation
+
+ The only purpose of unsynchronisation is to make the ID3v2 tag as
+ compatible as possible with existing software and hardware. There is
+ no use in 'unsynchronising' tags if the file is only to be processed
+ only by ID3v2 aware software and hardware. Unsynchronisation is only
+ useful with tags in MPEG 1/2 layer I, II and III, MPEG 2.5 and AAC
+ files.
+
+
+6.1. The unsynchronisation scheme
+
+ Whenever a false synchronisation is found within the tag, one zeroed
+ byte is inserted after the first false synchronisation byte. The
+ format of synchronisations that should be altered by ID3 encoders is
+ as follows:
+
+ %11111111 111xxxxx
+
+ and should be replaced with:
+
+ %11111111 00000000 111xxxxx
+
+ This has the side effect that all $FF 00 combinations have to be
+ altered, so they will not be affected by the decoding process.
+ Therefore all the $FF 00 combinations have to be replaced with the
+ $FF 00 00 combination during the unsynchronisation.
+
+ To indicate usage of the unsynchronisation, the unsynchronisation
+ flag in the frame header should be set. This bit MUST be set if the
+ frame was altered by the unsynchronisation and SHOULD NOT be set if
+ unaltered. If all frames in the tag are unsynchronised the
+ unsynchronisation flag in the tag header SHOULD be set. It MUST NOT
+ be set if the tag has a frame which is not unsynchronised.
+
+ Assume the first byte of the audio to be $FF. The special case when
+ the last byte of the last frame is $FF and no padding nor footer is
+ used will then introduce a false synchronisation. This can be solved
+ by adding a footer, adding padding or unsynchronising the frame and
+ add $00 to the end of the frame data, thus adding more byte to the
+ frame size than a normal unsynchronisation would. Although not
+ preferred, it is allowed to apply the last method on all frames
+ ending with $FF.
+
+ It is preferred that the tag is either completely unsynchronised or
+ not unsynchronised at all. A completely unsynchronised tag has no
+ false synchonisations in it, as defined above, and does not end with
+ $FF. A completely non-unsynchronised tag contains no unsynchronised
+ frames, and thus the unsynchronisation flag in the header is cleared.
+
+ Do bear in mind, that if compression or encryption is used, the
+ unsynchronisation scheme MUST be applied afterwards. When decoding an
+ unsynchronised frame, the unsynchronisation scheme MUST be reversed
+ first, encryption and decompression afterwards.
+
+
+6.2. Synchsafe integers
+
+ In some parts of the tag it is inconvenient to use the
+ unsychronisation scheme because the size of unsynchronised data is
+ not known in advance, which is particularly problematic with size
+ descriptors. The solution in ID3v2 is to use synchsafe integers, in
+ which there can never be any false synchs. Synchsafe integers are
+ integers that keep its highest bit (bit 7) zeroed, making seven bits
+ out of eight available. Thus a 32 bit synchsafe integer can store 28
+ bits of information.
+
+ Example:
+
+ 255 (%11111111) encoded as a 16 bit synchsafe integer is 383
+ (%00000001 01111111).
+
+
+7. Copyright
+
+ Copyright (C) Martin Nilsson 2000. All Rights Reserved.
+
+ This document and translations of it may be copied and furnished to
+ others, and derivative works that comment on or otherwise explain it
+ or assist in its implementation may be prepared, copied, published
+ and distributed, in whole or in part, without restriction of any
+ kind, provided that a reference to this document is included on all
+ such copies and derivative works. However, this document itself may
+ not be modified in any way and reissued as the original document.
+
+ The limited permissions granted above are perpetual and will not be
+ revoked.
+
+ This document and the information contained herein is provided on an
+ 'AS IS' basis and THE AUTHORS DISCLAIMS ALL WARRANTIES, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
+ THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
+ WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+
+8. References
+
+ [ID3v2] Martin Nilsson, 'ID3v2 informal standard'.
+
+ <url:http://www.id3.org/id3v2.3.0.txt>
+
+ [ISO-639-2] ISO/FDIS 639-2.
+ 'Codes for the representation of names of languages, Part 2: Alpha-3
+ code.' Technical committee / subcommittee: TC 37 / SC 2
+
+ [ISO-3309] ISO 3309
+ 'Information Processing Systems--Data Communication High-Level Data
+ Link Control Procedure--Frame Structure', IS 3309, October 1984, 3rd
+ Edition.
+
+ [ISO-8859-1] ISO/IEC DIS 8859-1.
+ '8-bit single-byte coded graphic character sets, Part 1: Latin
+ alphabet No. 1.' Technical committee / subcommittee: JTC 1 / SC 2
+
+ [JFIF] 'JPEG File Interchange Format, version 1.02'
+
+ <url:http://www.w3.org/Graphics/JPEG/jfif.txt>
+
+ [KEYWORDS] S. Bradner, 'Key words for use in RFCs to Indicate
+ Requirement Levels', RFC 2119, March 1997.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc2119.txt>
+
+ [MPEG] ISO/IEC 11172-3:1993.
+ 'Coding of moving pictures and associated audio for digital storage
+ media at up to about 1,5 Mbit/s, Part 3: Audio.'
+ Technical committee / subcommittee: JTC 1 / SC 29
+ and
+ ISO/IEC 13818-3:1995
+ 'Generic coding of moving pictures and associated audio information,
+ Part 3: Audio.'
+ Technical committee / subcommittee: JTC 1 / SC 29
+ and
+ ISO/IEC DIS 13818-3
+ 'Generic coding of moving pictures and associated audio information,
+ Part 3: Audio (Revision of ISO/IEC 13818-3:1995)'
+
+ [PNG] 'Portable Network Graphics, version 1.0'
+
+ <url:http://www.w3.org/TR/REC-png-multi.html>
+
+ [UNICODE] The Unicode Consortium,
+ 'The Unicode Standard Version 3.0', ISBN 0-201-61633-5.
+
+ <url:http://www.unicode.org/unicode/standard/versions/Unicode3.0.htm>
+
+ [URL] T. Berners-Lee, L. Masinter & M. McCahill, 'Uniform Resource
+ Locators (URL)', RFC 1738, December 1994.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc1738.txt>
+
+ [UTF-8] F. Yergeau, 'UTF-8, a transformation format of ISO 10646',
+ RFC 2279, January 1998.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc2279.txt>
+
+ [UTF-16] F. Yergeau, 'UTF-16, an encoding of ISO 10646', RFC 2781,
+ February 2000.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc2781.txt>
+
+ [ZLIB] P. Deutsch, Aladdin Enterprises & J-L. Gailly, 'ZLIB
+ Compressed Data Format Specification version 3.3', RFC 1950,
+ May 1996.
+
+ <url:ftp://ftp.isi.edu/in-notes/rfc1950.txt>
+
+
+9. Author's Address
+
+ Written by
+
+ Martin Nilsson
+ Rydsvägen 246 C. 30
+ SE-584 34 Linköping
+ Sweden
+
+ Email: nilsson@id3.org
+
projects / platform / upstream / gstreamer.git / commitdiff