[FFmpeg-devel] [PATCH] Speex parser

Michael Niedermayer michaelni
Mon Aug 31 15:13:59 CEST 2009

On Sun, Aug 30, 2009 at 06:12:13PM -0700, Baptiste Coudurier wrote:
> On 8/30/2009 5:50 PM, Justin Ruggles wrote:
> > [...]
> >
>> I still don't like that the decoder is required, but I guess that's the
>> design of lavf, so too bad for me. ;)
> Me neither, remuxing should work without the decoder.

and i of course dont like it either but this patch adds >300 lines of code
that are fuctionally duplicate to the decoder

The real itch people seem to have is that its an external dependancy, where
it internal using it to read one packet would hardly annoy anyone. Also
where it internal these 300 lines could be shared between decoder and
parser ...

So in summary the problem is (AFIAK)

0. Xiph didnt enforce the existence of the main header, that is their
   decoder implementation works without it
1. the way adobe decided to store speex in flv ommits this header
2. we need this header and information from it for remuxing
3. the decoder can figure out the needed information
4. we dont have a native decoder

A. flv does not store this header
B. ogg needs the header
-> we do need something between to build that header out of hot air
so its IMHO not just remuxing, that _does_ work without a decoder
its converting from a headerless to a headered format ...

things we can do
* as justin said speex should be added to the list of codecs needing a
  frame size, thats simply a bugfix
* extend bitstream filters to also filter extradata cleanly so they
  are able to change or fill in extradata
* write a native decoder or parser that extracts the needed information
  its ugly for just that but if people want it iam not going to object
  further, just keep in mind that the code should be shareable with a
  native decoder if one is written ...
* write a bitstream filter that converts from flv-speex to ogg-speex

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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