2 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
4 * gstvorbistag.c: library for reading / modifying vorbis tags
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
23 * SECTION:gsttagvorbis
24 * @short_description: tag mappings and support functions for plugins
25 * dealing with vorbiscomments
26 * @see_also: #GstTagList
30 * Contains various utility functions for plugins to parse or create
31 * vorbiscomments and map them to and from #GstTagList<!-- -->s.
39 #include <gst/gsttagsetter.h>
40 #include <gst/base/gstbytereader.h>
41 #include <gst/base/gstbytewriter.h>
42 #include "gsttageditingprivate.h"
47 * see http://xiph.org/ogg/vorbis/doc/v-comment.html
49 static const GstTagEntryMatch tag_matches[] = {
50 {GST_TAG_TITLE, "TITLE"},
51 {GST_TAG_VERSION, "VERSION"},
52 {GST_TAG_ALBUM, "ALBUM"},
53 {GST_TAG_TRACK_NUMBER, "TRACKNUMBER"},
54 {GST_TAG_ALBUM_VOLUME_NUMBER, "DISCNUMBER"},
55 {GST_TAG_TRACK_COUNT, "TRACKTOTAL"},
56 {GST_TAG_ALBUM_VOLUME_COUNT, "DISCTOTAL"},
57 {GST_TAG_ARTIST, "ARTIST"},
58 {GST_TAG_PERFORMER, "PERFORMER"},
59 {GST_TAG_COMPOSER, "COMPOSER"},
60 {GST_TAG_COPYRIGHT, "COPYRIGHT"},
61 {GST_TAG_LICENSE, "LICENSE"},
62 {GST_TAG_LICENSE_URI, "LICENSE"},
63 {GST_TAG_GEO_LOCATION_NAME, "LOCATION"},
64 {GST_TAG_ORGANIZATION, "ORGANIZATION"},
65 {GST_TAG_DESCRIPTION, "DESCRIPTION"},
66 {GST_TAG_GENRE, "GENRE"},
67 {GST_TAG_DATE, "DATE"},
68 {GST_TAG_CONTACT, "CONTACT"},
69 {GST_TAG_ISRC, "ISRC"},
70 {GST_TAG_COMMENT, "COMMENT"},
71 {GST_TAG_TRACK_GAIN, "REPLAYGAIN_TRACK_GAIN"},
72 {GST_TAG_TRACK_PEAK, "REPLAYGAIN_TRACK_PEAK"},
73 {GST_TAG_ALBUM_GAIN, "REPLAYGAIN_ALBUM_GAIN"},
74 {GST_TAG_ALBUM_PEAK, "REPLAYGAIN_ALBUM_PEAK"},
75 {GST_TAG_REFERENCE_LEVEL, "REPLAYGAIN_REFERENCE_LOUDNESS"},
76 {GST_TAG_MUSICBRAINZ_TRACKID, "MUSICBRAINZ_TRACKID"},
77 {GST_TAG_MUSICBRAINZ_ARTISTID, "MUSICBRAINZ_ARTISTID"},
78 {GST_TAG_MUSICBRAINZ_ALBUMID, "MUSICBRAINZ_ALBUMID"},
79 {GST_TAG_MUSICBRAINZ_ALBUMARTISTID, "MUSICBRAINZ_ALBUMARTISTID"},
80 {GST_TAG_MUSICBRAINZ_TRMID, "MUSICBRAINZ_TRMID"},
81 {GST_TAG_ARTIST_SORTNAME, "ARTISTSORT"},
82 {GST_TAG_ARTIST_SORTNAME, "ARTISTSORTORDER"},
83 {GST_TAG_ARTIST_SORTNAME, "MUSICBRAINZ_SORTNAME"},
84 {GST_TAG_ALBUM_SORTNAME, "ALBUMSORT"},
85 {GST_TAG_ALBUM_SORTNAME, "ALBUMSORTORDER"},
86 {GST_TAG_TITLE_SORTNAME, "TITLESORT"},
87 {GST_TAG_TITLE_SORTNAME, "TITLESORTORDER"},
88 {GST_TAG_ALBUM_ARTIST, "ALBUMARTIST"},
89 {GST_TAG_ALBUM_ARTIST_SORTNAME, "ALBUMARTISTSORT"},
90 {GST_TAG_ALBUM_ARTIST_SORTNAME, "ALBUMARTISTSORTORDER"},
91 {GST_TAG_LANGUAGE_CODE, "LANGUAGE"},
92 {GST_TAG_CDDA_MUSICBRAINZ_DISCID, "MUSICBRAINZ_DISCID"},
93 {GST_TAG_CDDA_CDDB_DISCID, "DISCID"},
94 /* For the apparent de-facto standard for coverart in vorbis comments, see:
95 * http://www.hydrogenaudio.org/forums/lofiversion/index.php/t48386.html */
96 {GST_TAG_PREVIEW_IMAGE, "COVERART"},
97 /* some evidence that "BPM" is used elsewhere:
98 * http://mail.kde.org/pipermail/amarok/2006-May/000090.html
100 {GST_TAG_BEATS_PER_MINUTE, "BPM"},
105 * gst_tag_from_vorbis_tag:
106 * @vorbis_tag: vorbiscomment tag to convert to GStreamer tag
108 * Looks up the GStreamer tag for a vorbiscomment tag.
110 * Returns: The corresponding GStreamer tag or NULL if none exists.
112 G_CONST_RETURN gchar *
113 gst_tag_from_vorbis_tag (const gchar * vorbis_tag)
116 gchar *real_vorbis_tag;
118 g_return_val_if_fail (vorbis_tag != NULL, NULL);
120 gst_tag_register_musicbrainz_tags ();
122 real_vorbis_tag = g_ascii_strup (vorbis_tag, -1);
123 while (tag_matches[i].gstreamer_tag != NULL) {
124 if (strcmp (real_vorbis_tag, tag_matches[i].original_tag) == 0) {
129 g_free (real_vorbis_tag);
130 return tag_matches[i].gstreamer_tag;
134 * gst_tag_to_vorbis_tag:
135 * @gst_tag: GStreamer tag to convert to vorbiscomment tag
137 * Looks up the vorbiscomment tag for a GStreamer tag.
139 * Returns: The corresponding vorbiscomment tag or NULL if none exists.
141 G_CONST_RETURN gchar *
142 gst_tag_to_vorbis_tag (const gchar * gst_tag)
146 g_return_val_if_fail (gst_tag != NULL, NULL);
148 gst_tag_register_musicbrainz_tags ();
150 while (tag_matches[i].gstreamer_tag != NULL) {
151 if (strcmp (gst_tag, tag_matches[i].gstreamer_tag) == 0) {
152 return tag_matches[i].original_tag;
161 * gst_vorbis_tag_add:
162 * @list: a #GstTagList
163 * @tag: a vorbiscomment tag string (key in key=value), must be valid UTF-8
164 * @value: a vorbiscomment value string (value in key=value), must be valid UTF-8
166 * Convenience function using gst_tag_from_vorbis_tag(), parsing
167 * a vorbis comment string into the right type and adding it to the
168 * given taglist @list.
170 * Unknown vorbiscomment tags will be added to the tag list in form
171 * of a #GST_TAG_EXTENDED_COMMENT (since 0.10.10 at least).
174 gst_vorbis_tag_add (GstTagList * list, const gchar * tag, const gchar * value)
176 const gchar *gst_tag;
179 g_return_if_fail (list != NULL);
180 g_return_if_fail (tag != NULL);
181 g_return_if_fail (value != NULL);
183 g_return_if_fail (g_utf8_validate (tag, -1, NULL));
184 g_return_if_fail (g_utf8_validate (value, -1, NULL));
185 g_return_if_fail (strchr (tag, '=') == NULL);
187 gst_tag = gst_tag_from_vorbis_tag (tag);
188 if (gst_tag == NULL) {
191 ext_comment = g_strdup_printf ("%s=%s", tag, value);
192 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, GST_TAG_EXTENDED_COMMENT,
194 g_free (ext_comment);
198 tag_type = gst_tag_get_type (gst_tag);
203 gboolean is_track_number_tag;
204 gboolean is_disc_number_tag;
206 is_track_number_tag = (strcmp (gst_tag, GST_TAG_TRACK_NUMBER) == 0);
207 is_disc_number_tag = (strcmp (gst_tag, GST_TAG_ALBUM_VOLUME_NUMBER) == 0);
208 tmp = strtoul (value, &check, 10);
209 if (*check == '/' && (is_track_number_tag || is_disc_number_tag)) {
213 count = strtoul (check, &check, 10);
214 if (*check != '\0' || count == 0)
216 if (is_track_number_tag) {
217 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, GST_TAG_TRACK_COUNT,
220 gst_tag_list_add (list, GST_TAG_MERGE_APPEND,
221 GST_TAG_ALBUM_VOLUME_COUNT, count, NULL);
224 if (*check == '\0') {
225 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, gst_tag, tmp, NULL);
232 /* specialcase for language code */
233 if (strcmp (tag, "LANGUAGE") == 0) {
234 const gchar *s = strchr (value, '[');
236 /* Accept both ISO-639-1 and ISO-639-2 codes */
237 if (s && strchr (s, ']') == s + 4) {
238 valid = g_strndup (s + 1, 3);
239 } else if (s && strchr (s, ']') == s + 3) {
240 valid = g_strndup (s + 1, 2);
241 } else if (strlen (value) != 2 && strlen (value) != 3) {
242 GST_WARNING ("doesn't contain an ISO-639 language code: %s", value);
244 } else if (strcmp (tag, "LICENSE") == 0) {
245 /* license tags in vorbis comments must contain an URI representing
246 * the license and nothing more, at least according to:
247 * http://wiki.xiph.org/index.php/LICENSE_and_COPYRIGHT_tags_on_Vorbis_Comments */
248 if (value && gst_uri_is_valid (value))
249 gst_tag = GST_TAG_LICENSE_URI;
253 valid = g_strdup (value);
255 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, gst_tag, valid, NULL);
262 c = g_strdup (value);
263 g_strdelimit (c, ",", '.');
264 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, gst_tag,
265 g_strtod (c, NULL), NULL);
270 if (tag_type == GST_TYPE_DATE) {
271 guint y, d = 1, m = 1;
272 gchar *check = (gchar *) value;
274 y = strtoul (check, &check, 10);
277 m = strtoul (check, &check, 10);
280 d = strtoul (check, &check, 10);
284 /* accept dates like 2007-00-00 and 2007-05-00 */
286 if (m == 0 && d == 0)
288 else if (m != 0 && d == 0)
292 /* date might be followed by a time */
293 if ((*check == '\0' || g_ascii_isspace (*check)) && y != 0 &&
294 g_date_valid_dmy (d, m, y)) {
297 date = g_date_new_dmy (d, m, y);
298 gst_tag_list_add (list, GST_TAG_MERGE_APPEND, gst_tag, date, NULL);
301 GST_DEBUG ("skipping invalid date '%s' (%u,%u,%u)", value, y, m, d);
304 GST_WARNING ("Unhandled tag of type '%s' (%d)",
305 g_type_name (tag_type), (gint) tag_type);
313 gst_vorbis_tag_add_coverart (GstTagList * tags, gchar * img_data_base64,
320 goto not_enough_data;
322 /* img_data_base64 points to a temporary copy of the base64 encoded data, so
323 * it's safe to do inpace decoding here
325 g_base64_decode_inplace (img_data_base64, &img_len);
330 gst_tag_image_data_to_image_buffer ((const guint8 *) img_data_base64,
331 img_len, GST_TAG_IMAGE_TYPE_NONE);
336 gst_tag_list_add (tags, GST_TAG_MERGE_APPEND,
337 GST_TAG_PREVIEW_IMAGE, img, NULL);
339 gst_buffer_unref (img);
345 GST_WARNING ("COVERART tag with too little base64-encoded data");
350 GST_WARNING ("Couldn't decode base64 image data from COVERART tag");
355 GST_WARNING ("Couldn't extract image or image type from COVERART tag");
360 /* Standardized way of adding pictures to vorbiscomments:
361 * http://wiki.xiph.org/VorbisComment#METADATA_BLOCK_PICTURE
364 gst_vorbis_tag_add_metadata_block_picture (GstTagList * tags,
365 gchar * value, gint value_len)
367 GstByteReader reader;
368 guint32 img_len = 0, img_type = 0;
369 guint32 img_mimetype_len = 0, img_description_len = 0;
371 const guint8 *data = NULL;
373 /* img_data_base64 points to a temporary copy of the base64 encoded data, so
374 * it's safe to do inpace decoding here
376 g_base64_decode_inplace (value, &decoded_len);
377 if (decoded_len == 0)
380 gst_byte_reader_init (&reader, (guint8 *) value, decoded_len);
382 if (!gst_byte_reader_get_uint32_be (&reader, &img_type))
385 if (!gst_byte_reader_get_uint32_be (&reader, &img_mimetype_len))
387 if (!gst_byte_reader_skip (&reader, img_mimetype_len))
390 if (!gst_byte_reader_get_uint32_be (&reader, &img_description_len))
392 if (!gst_byte_reader_skip (&reader, img_description_len))
395 /* Skip width, height, color depth and number of colors for
397 if (!gst_byte_reader_skip (&reader, 4 * 4))
400 if (!gst_byte_reader_get_uint32_be (&reader, &img_len))
403 if (!gst_byte_reader_get_data (&reader, img_len, &data))
406 gst_tag_list_add_id3_image (tags, data, img_len, img_type);
412 ("Couldn't extract image or image type from METADATA_BLOCK_PICTURE tag");
415 GST_WARNING ("Failed to decode Base64 data from METADATA_BLOCK_PICTURE tag");
420 * gst_tag_list_from_vorbiscomment:
421 * @data: data to convert
422 * @size: size of @data
423 * @id_data: identification data at start of stream
424 * @id_data_length: length of identification data
425 * @vendor_string: pointer to a string that should take the vendor string
426 * of this vorbis comment or NULL if you don't need it.
428 * Creates a new tag list that contains the information parsed out of a
429 * vorbiscomment packet.
431 * Returns: A new #GstTagList with all tags that could be extracted from the
432 * given vorbiscomment buffer or NULL on error.
435 gst_tag_list_from_vorbiscomment (const guint8 * data, gsize size,
436 const guint8 * id_data, const guint id_data_length, gchar ** vendor_string)
438 #define ADVANCE(x) G_STMT_START{ \
441 if (size < 4) goto error; \
442 cur_size = GST_READ_UINT32_LE (data); \
445 if (cur_size > size) goto error; \
446 cur = (gchar*)data; \
454 g_return_val_if_fail (data != NULL, NULL);
455 g_return_val_if_fail (id_data != NULL || id_data_length == 0, NULL);
457 list = gst_tag_list_new ();
459 if (size < 11 || size <= id_data_length + 4)
462 if (id_data_length > 0 && memcmp (data, id_data, id_data_length) != 0)
465 ADVANCE (id_data_length);
468 *vendor_string = g_strndup (cur, cur_size);
471 iterations = cur_size;
477 cur = g_strndup (cur, cur_size);
478 value = strchr (cur, '=');
485 value_len = strlen (value);
486 if (value_len == 0 || !g_utf8_validate (value, value_len, NULL)) {
490 /* we'll just ignore COVERARTMIME and typefind the image data */
491 if (g_ascii_strcasecmp (cur, "COVERARTMIME") == 0) {
493 } else if (g_ascii_strcasecmp (cur, "COVERART") == 0) {
494 gst_vorbis_tag_add_coverart (list, value, value_len);
495 } else if (g_ascii_strcasecmp (cur, "METADATA_BLOCK_PICTURE") == 0) {
496 gst_vorbis_tag_add_metadata_block_picture (list, value, value_len);
498 gst_vorbis_tag_add (list, cur, value);
506 gst_tag_list_free (list);
512 * gst_tag_list_from_vorbiscomment_buffer:
513 * @buffer: buffer to convert
514 * @id_data: identification data at start of stream
515 * @id_data_length: length of identification data
516 * @vendor_string: pointer to a string that should take the vendor string
517 * of this vorbis comment or NULL if you don't need it.
519 * Creates a new tag list that contains the information parsed out of a
520 * vorbiscomment packet.
522 * Returns: A new #GstTagList with all tags that could be extracted from the
523 * given vorbiscomment buffer or NULL on error.
526 gst_tag_list_from_vorbiscomment_buffer (GstBuffer * buffer,
527 const guint8 * id_data, const guint id_data_length, gchar ** vendor_string)
533 data = gst_buffer_map (buffer, &size, NULL, GST_MAP_READ);
535 gst_tag_list_from_vorbiscomment (data, size, id_data, id_data_length,
537 gst_buffer_unmap (buffer, data, size);
551 gst_tag_to_metadata_block_picture (const gchar * tag,
552 const GValue * image_value)
555 gchar *comment_data, *data_result;
556 const gchar *mime_type;
558 GstStructure *mime_struct;
565 GstByteWriter writer;
566 GstTagImageType image_type = GST_TAG_IMAGE_TYPE_NONE;
567 gint width = 0, height = 0;
568 guint8 *metadata_block;
569 guint metadata_block_len;
572 g_return_val_if_fail (image_value != NULL, NULL);
574 /* FIXME, no more buffer caps */
575 g_assert_not_reached ();
578 buffer = gst_value_get_buffer (image_value);
579 g_return_val_if_fail (gst_caps_is_fixed (buffer->caps), NULL);
580 mime_struct = gst_caps_get_structure (buffer->caps, 0);
582 mime_type = gst_structure_get_name (mime_struct);
583 if (strcmp (mime_type, "text/uri-list") == 0)
585 mime_type_len = strlen (mime_type);
587 gst_structure_get (mime_struct, "image-type", GST_TYPE_TAG_IMAGE_TYPE,
588 &image_type, "width", G_TYPE_INT, &width, "height", G_TYPE_INT, &height,
591 metadata_block_len = 32 + mime_type_len + gst_buffer_get_size (buffer);
592 gst_byte_writer_init_with_size (&writer, metadata_block_len, TRUE);
594 if (image_type == GST_TAG_IMAGE_TYPE_NONE
595 && strcmp (tag, GST_TAG_PREVIEW_IMAGE) == 0) {
596 gst_byte_writer_put_uint32_be_unchecked (&writer, 0x01);
598 /* Convert to ID3v2 APIC image type */
599 if (image_type == GST_TAG_IMAGE_TYPE_NONE)
600 image_type = GST_TAG_IMAGE_TYPE_UNDEFINED;
602 image_type = image_type + 2;
603 gst_byte_writer_put_uint32_be_unchecked (&writer, image_type);
606 gst_byte_writer_put_uint32_be_unchecked (&writer, mime_type_len);
607 gst_byte_writer_put_data_unchecked (&writer, (guint8 *) mime_type,
609 /* description length */
610 gst_byte_writer_put_uint32_be_unchecked (&writer, 0);
611 gst_byte_writer_put_uint32_be_unchecked (&writer, width);
612 gst_byte_writer_put_uint32_be_unchecked (&writer, height);
614 gst_byte_writer_put_uint32_be_unchecked (&writer, 0);
615 /* for indexed formats the number of colors */
616 gst_byte_writer_put_uint32_be_unchecked (&writer, 0);
618 data = gst_buffer_map (buffer, &size, NULL, GST_MAP_READ);
619 gst_byte_writer_put_uint32_be_unchecked (&writer, size);
620 gst_byte_writer_put_data_unchecked (&writer, data, size);
621 gst_buffer_unmap (buffer, data, size);
623 g_assert (gst_byte_writer_get_pos (&writer) == metadata_block_len);
625 metadata_block = gst_byte_writer_reset_and_get_data (&writer);
626 comment_data = g_base64_encode (metadata_block, metadata_block_len);
627 g_free (metadata_block);
628 data_result = g_strdup_printf ("METADATA_BLOCK_PICTURE=%s", comment_data);
629 g_free (comment_data);
631 l = g_list_append (l, data_result);
638 * gst_tag_to_vorbis_comments:
639 * @list: a #GstTagList
640 * @tag: a GStreamer tag identifier, such as #GST_TAG_ARTIST
642 * Creates a new tag list that contains the information parsed out of a
643 * vorbiscomment packet.
645 * Returns: A #GList of newly-allowcated key=value strings. Free with
646 * g_list_foreach (list, (GFunc) g_free, NULL) plus g_list_free (list)
649 gst_tag_to_vorbis_comments (const GstTagList * list, const gchar * tag)
651 const gchar *vorbis_tag = NULL;
655 g_return_val_if_fail (list != NULL, NULL);
656 g_return_val_if_fail (tag != NULL, NULL);
658 /* Special case: cover art is split into two tags to store data and
659 * MIME-type. Even if the tag list contains multiple entries, there is
660 * no reasonable way to save more than one.
661 * If both, preview image and image, are present we prefer the
664 if ((strcmp (tag, GST_TAG_PREVIEW_IMAGE) == 0 &&
665 gst_tag_list_get_tag_size (list, GST_TAG_IMAGE) == 0) ||
666 strcmp (tag, GST_TAG_IMAGE) == 0) {
667 return gst_tag_to_metadata_block_picture (tag,
668 gst_tag_list_get_value_index (list, tag, 0));
671 if (strcmp (tag, GST_TAG_EXTENDED_COMMENT) != 0) {
672 vorbis_tag = gst_tag_to_vorbis_tag (tag);
677 /* FIXME: for tags that can map to multiple vorbis comment keys, add all
678 * of the possible keys */
679 for (i = 0; i < gst_tag_list_get_tag_size (list, tag); i++) {
680 GType tag_type = gst_tag_get_type (tag);
681 gchar *result = NULL;
687 if (!gst_tag_list_get_uint_index (list, tag, i, &u))
688 g_return_val_if_reached (NULL);
689 result = g_strdup_printf ("%s=%u", vorbis_tag, u);
693 const gchar *str = NULL;
695 if (!gst_tag_list_peek_string_index (list, tag, i, &str))
696 g_return_val_if_reached (NULL);
698 /* special case: GST_TAG_EXTENDED_COMMENT */
699 if (vorbis_tag == NULL) {
700 gchar *key = NULL, *val = NULL;
702 if (gst_tag_parse_extended_comment (str, &key, NULL, &val, TRUE)) {
703 result = g_strdup_printf ("%s=%s", key, val);
707 GST_WARNING ("Not a valid extended comment string: %s", str);
711 result = g_strdup_printf ("%s=%s", vorbis_tag, str);
717 gchar buf[G_ASCII_DTOSTR_BUF_SIZE];
719 if (!gst_tag_list_get_double_index (list, tag, i, &value))
720 g_return_val_if_reached (NULL);
721 g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, "%f", value);
722 result = g_strconcat (vorbis_tag, "=", buf, NULL);
726 if (tag_type == GST_TYPE_DATE) {
729 if (!gst_tag_list_get_date_index (list, tag, i, &date))
730 g_return_val_if_reached (NULL);
732 /* vorbis suggests using ISO date formats */
734 g_strdup_printf ("%s=%04d-%02d-%02d", vorbis_tag,
735 (gint) g_date_get_year (date), (gint) g_date_get_month (date),
736 (gint) g_date_get_day (date));
739 GST_DEBUG ("Couldn't write tag %s", tag);
745 l = g_list_prepend (l, result);
748 return g_list_reverse (l);
752 write_one_tag (const GstTagList * list, const gchar * tag, gpointer user_data)
754 MyForEach *data = (MyForEach *) user_data;
758 comments = gst_tag_to_vorbis_comments (list, tag);
760 for (it = comments; it != NULL; it = it->next) {
761 gchar *result = it->data;
764 data->data_count += strlen (result);
765 data->entries = g_list_prepend (data->entries, result);
768 g_list_free (comments);
772 * gst_tag_list_to_vorbiscomment_buffer:
773 * @list: tag list to convert
774 * @id_data: identification data at start of stream
775 * @id_data_length: length of identification data, may be 0 if @id_data is NULL
776 * @vendor_string: string that describes the vendor string or NULL
778 * Creates a new vorbiscomment buffer from a tag list.
780 * Returns: A new #GstBuffer containing a vorbiscomment buffer with all tags
781 * that could be converted from the given tag list.
784 gst_tag_list_to_vorbiscomment_buffer (const GstTagList * list,
785 const guint8 * id_data, const guint id_data_length,
786 const gchar * vendor_string)
789 guint8 *data, *odata;
792 MyForEach my_data = { 0, 0, NULL };
796 g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);
797 g_return_val_if_fail (id_data != NULL || id_data_length == 0, NULL);
799 if (vendor_string == NULL)
800 vendor_string = "GStreamer encoded vorbiscomment";
801 vendor_len = strlen (vendor_string);
802 required_size = id_data_length + 4 + vendor_len + 4 + 1;
803 gst_tag_list_foreach ((GstTagList *) list, write_one_tag, &my_data);
804 required_size += 4 * my_data.count + my_data.data_count;
806 buffer = gst_buffer_new_and_alloc (required_size);
807 odata = data = gst_buffer_map (buffer, NULL, NULL, GST_MAP_WRITE);
808 if (id_data_length > 0) {
809 memcpy (data, id_data, id_data_length);
810 data += id_data_length;
812 GST_WRITE_UINT32_LE (data, vendor_len);
814 memcpy (data, vendor_string, vendor_len);
816 l = my_data.entries = g_list_reverse (my_data.entries);
817 GST_WRITE_UINT32_LE (data, my_data.count);
819 for (i = 0; i < my_data.count; i++) {
823 g_assert (l != NULL);
827 GST_WRITE_UINT32_LE (data, size);
829 memcpy (data, cur, size);
832 g_list_foreach (my_data.entries, (GFunc) g_free, NULL);
833 g_list_free (my_data.entries);
835 gst_buffer_unmap (buffer, odata, required_size);