AW: AW: AW: [vorbis-dev] Chained streams and granule position

[Tor-Einar Jarnbjo]

> How does the demux knows that type id magic number xxxx corresponds to
> application/vorbis? Let's say that you have put your vorbis-pluging,
> who registers for application/vorbis. Now, somebody implements vorbis
> on wav, and so they put a new number on the wFormatTag field, lets say
> x0123. Specifically, who's in charge of determinig that
> wFormatTag=x0123 means 'application/vorbis'? The codec (in which case
> he should know about all the file types on which he is implemented) or
> the demux (in which case he needs to know about all the decoders that
> he supports)?

It does not, if not told to know. But, for the possible known content types,
it would for example for WAV be enough to have a table like:

0x0000 -> PCM
0x0001 -> aLaw
0x0002 -> uLaw
0x0003 -> ADPCM
0x0100 -> MP3
0x0312 -> GSM

... and so on (the number are probably not really correct for WAV).

The difference in the case of Ogg is, that a demux has to analyze the
content and contain specific logic to recognize each content type.

<p>> Second question: have you read the thread I posted about?
> http://www.xiph.org/archives/theora-dev/200209/0040.html

Some of it, yes.

<p>Tor

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