[vorbis-dev] Feedback on Ogg Speex file format

[Jean-Marc Valin]

Hi,

I'm the main author of Speex (http://speex.sourceforge.net), an
open-source speech codec that uses Ogg for file storage. I'd like to
have feedback on the way we store Speex data in Ogg files to make sure
we do the right thing. The Speex documentation can be found at
http://speex.sourceforge.net/manual/ but here's the part about Ogg:

<p><p>Speex bit-streams can be stored in Ogg files. In this case, the first
packet of the Ogg file contains the Speex header described in table 4.
All integer fields in the headers are stored as little-endian. The
speex_string field must contain the ``Speex   `` (with 3 training
spaces), which identifies the bit-stream. The next field, speex_version
contains the version of Speex that encoded the file. For now, refer to
speex_header.[ch] for more info. The beginning of stream (b_o_s) flag is
set to 1 for the header. The header packet has packetno=0 and
granulepos=0.

The second packet contains a user-comment string, without terminating
null. The content/format of the comment string is not defined. This
packet has packetno=1 and granulepos=0.

The third and subsequant packets each contain one or more (number found
in header) Speex frames. These are identified with packetno starting
from 2 and the granulepos is the number of the first sample encoded in
that packet.

The stream is terminated by a packet containing the string ``END OF
STREAM'' (without terminating null). The the end of stream (e_o_s) flag
set to 1. The decoder should rely on the e_o_s flag and not on the
content of the packet. 

<p><p>Any error we made? suggestions?
Thanks,

        Jean-Marc


-- 
Jean-Marc Valin, M.Sc.A.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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