[vlc-devel] Speex audio in .flv container

Derk-Jan Hartman hartman at videolan.org
Mon Sep 1 11:23:06 CEST 2008

On 29 aug 2008, at 23:13, Steven Woolley wrote:
> Thanks!
> Indeed, it doesn't appear to be able to be decoded!?!  I have no  
> clue what "extradata" is or would be?  Is that something associated  
> with the .ogg container or is it really something that we need to  
> decode it? (apparently it's not totally needed since the flash  
> player itself can decode the example file I gave and play it just  
> fine)

extradata is the paramaters that were used to encode and are  
"required" to decode. They are usually present in the header of a  
file. If these are indeed no where to be found, then 1 adobe is stupid  
and 2 they should fix it in my humble opinion.

> Does anyone know if the www.speex.org codec needs this "extradata"?   
> Is there some command that will just dump the audio frames as is to  
> stdout so I can pipe them to speexdec?
> Ideally though it would be implemented in mencoder or ffmpeg (so I  
> we can do videos with audio in sync without using a other software).
> Should I file another enhancement to overcome this "extradata" issue?

This is likely something that should be fixed in ffmpeg yes.


> On Fri, Aug 29, 2008 at 12:10 PM, Baptiste Coudurier <baptiste.coudurier at smartjog.com 
> > wrote:
> Hi,
> Steven Woolley wrote:
> > Hi all, I'm messing with the flash player 10 beta, which allows  
> audio
> > to be recorded in Speex format, but having a hard time converting it
> > to anything else from the .flv.  I'm betting this will become a lot
> > more common in the future given the openness and lack of patents for
> > Speex vs. other flash audio codec's (nellymoser in particular).
> >
> >
> > In a nutshell, speex in a .flv is new enough that noone supports it
> > yet (and I'm not even sure the .flv's I'm generating are correct,  
> but
> > noone is, because until you have something that will read it,  
> there's
> > now way to say it's working or not!)
> >
> > All I do know is that both vlc and ffmpeg give "Unsupported audio  
> codec" errors.
> >
> > So, a) is there any way to get vlc or ffmpeg to work with speex?   
> I am
> > willing to do a custom compile, change code, etc. (if I knew where  
> to start!)
> >
> > or b) failing that, how do I simply output the raw speex audio  
> stream from
> > the flv to a pipe or file? So I can decode it with the official  
> speex stuff?
> >
> FFmpeg r15028 flv demuxer now supports speex.
> It seems speex in flv does not embed extradata however (could not find
> it in the file I got), so decoder might need some tweaking.
> --
> Baptiste COUDURIER                              GnuPG Key Id:  
> 0x5C1ABAAA
> Smartjog USA Inc.                                http://www.smartjog.com
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