-<HTML><HEAD><TITLE>xiph.org: OggSquish Vorbis documentation</TITLE>
+<HTML><HEAD><TITLE>xiph.org: Ogg Vorbis documentation</TITLE>
<BODY bgcolor="#ffffff" text="#202020" link="#006666" vlink="#000000">
-<nobr><a href="vorbis.html"><img src="white-ogg.
gif" border=0><img
-src="vorbisword2.
gif" border=0></a></nobr><p>
+<nobr><a href="vorbis.html"><img src="white-ogg.
png" border=0><img
+src="vorbisword2.
png" border=0></a></nobr><p>
<h1><font color=#000070>
-OggSquish logical bitstream framing
+Ogg logical bitstream framing
</font></h1>
<em>Last update to this document: July 15, 1999</em><br>
-<h2>OggSquish bitstreams</h2>
+<h2>Ogg bitstreams</h2>
Vorbis encodes short-time blocks of PCM data into raw packets of
bit-packed data. These raw packets may be used directly by transport
mechanisms that provide their own framing and packet-seperation
mechanisms (such as UDP datagrams). For stream based storage (such as
files) and transport (such as TCP streams or pipes), Vorbis uses the
-OggSquish bitstream format to provide framing/sync, sync recapture
+Ogg bitstream format to provide framing/sync, sync recapture
after error, landmarks during seeking, and enough information to
properly seperate data back into packets at the original packet
boundaries without relying on decoding to find packet boundaries.<p>
-<h2>Design constraints for OggSquish bitstreams</h2>
+<h2>Design constraints for Ogg bitstreams</h2>
<ol><li>True streaming; we must not need to seek to build a 100%
complete bitstream.
<h2>Logical and Physical Bitstreams</h2>
-A <em>logical</em> OggSquish bitstream is a contiguous stream of
+A <em>logical</em> Ogg bitstream is a contiguous stream of
sequential pages belonging only to the logical bitstream. A
-<em>physical</em> OggSquish bitstream is constructed from one or more
-than one logical OggSquish bitstream (the simplest physical bitstream
+<em>physical</em> Ogg bitstream is constructed from one or more
+than one logical Ogg bitstream (the simplest physical bitstream
is simply a single logical bitstream). We describe below the exact
-formatting of an OggSquish logical bitstream. Combining logical
+formatting of an Ogg logical bitstream. Combining logical
bitstreams into more complex physical bitstreams is described in the
-<a href="oggstream.html">OggSquish bitstream overview</a>. The exact
+<a href="oggstream.html">Ogg bitstream overview</a>. The exact
mapping of raw Vorbis packets into a valid Ogg Vorbis physical
bitstream is described in <a href="vorbis-stream.html">Vorbis
bitstream mapping</a>.
<h2>Bitstream structure</h2>
-An OggSquish stream is structured by dividing incoming packets into
+An Ogg stream is structured by dividing incoming packets into
segments of up to 255 bytes and then wrapping a group of contiguous
packet segments into a variable length page preceeded by a page
header. Both the header size and page size are variable; the page
Packets are not resticted to beginning and ending within a page,
although individual segments are, by definition, required to do so.
Packets are not restricted to a maximum size, although excessively
-large packets in the data stream are discouraged; the OggSquish
+large packets in the data stream are discouraged; the Ogg
bitstream specification strongly recommends nominal page size of
approximately 4-8kB (large packets are forseen as being useful for
initialization data at the beginning of a logical bitstream).<p>
<h4>PCM absolute position</h4>
- (This is packed in the same way the rest of OggSquish data is packed;
+ (This is packed in the same way the rest of Ogg data is packed;
LSb of LSB first. Note that the 'position' data specifies a 'sample'
number (eg, in a CD quality sample is four octets, 16 bits for left
and 16 bits for right; in video it would be the frame number). The
<h4>stream serial number</h4>
- OggSquish allows for seperate logical bitstreams to be mixed at page
+ Ogg allows for seperate logical bitstreams to be mixed at page
granularity in a physical bitstream. The most common case would be
sequential arrangement, but it is possible to interleave pages for
two seperate bitstreams to be decoded concurrently. The serial
<hr>
<a href="http://www.xiph.org/">
-<img src="white-xifish.gif" align=left border=0>
+<img src="white-xifish.png" align=left border=0>
</a>
<font size=-2 color=#505050>
-Ogg
Squish is a <a href="http://www.xiph.org">Xiphophorus</a> effort to
+Ogg is a <a href="http://www.xiph.org">Xiphophorus</a> effort to
protect essential tenets of Internet multimedia from corporate
hostage-taking; Open Source is the net's greatest tool to keep
everyone honest. See <a href="http://www.xiph.org/about.html">About
Xiphophorus</a> for details.
<p>
-Ogg Vorbis is the first OggSquish audio CODEC. Anyone may
-freely use and distribute the OggSquish and Vorbis specification,
+Ogg Vorbis is the first Ogg audio CODEC. Anyone may
+freely use and distribute the Ogg and Vorbis specification,
whether in a private, public or corporate capacity. However,
Xiphophorus and the Ogg project (xiph.org) reserve the right to set
the Ogg/Vorbis specification and certify specification compliance.<p>
-Xiphophorus's Vorbis software CODEC implementation (libvorbis and the
-vorbis encode/decode/playback utility) are distributed under the GNU
-Public License. This does not restrict third parties from
-distributing independent implementations of Vorbis software under
-other licenses.<p>
+Xiphophorus's Vorbis software CODEC implementation is distributed
+under the Lessr/Library GNU Public License. This does not restrict
+third parties from distributing independent implementations of Vorbis
+software under other licenses.<p>
OggSquish, Vorbis, Xiphophorus and their logos are trademarks (tm) of
<a href="http://www.xiph.org/">Xiphophorus</a>. These pages are
-copyright (C) 1994-
1999 Xiphophorus. All rights reserved.<p>
+copyright (C) 1994-
2000 Xiphophorus. All rights reserved.<p>
</body>
projects / platform / upstream / libvorbis.git / blobdiff