[FFmpeg-devel] [PATCH] Speex decoding via libspeex

David Conrad lessen42
Wed Oct 22 05:17:48 CEST 2008

On Oct 21, 2008, at 3:17 PM, Art Clarke wrote:

> On Mon, Oct 20, 2008 at 11:45 PM, David Conrad <lessen42 at gmail.com>  
> wrote:
>> On Oct 21, 2008, at 2:36 AM, Diego Biurrun wrote:
>>> On Tue, Oct 21, 2008 at 02:30:01AM -0400, David Conrad wrote:
>>>> This adds decode support for Speex using libspeex. Tested with
>>>> talk109-
>>>> q5.spx and speexaudio.flv
>>>> I'm not sure the best way to handle Speex in flv;
>>> Since when does Speex exist in flv?  Isn't Ogg the preferred
>>> container?
>> Since Flash 10 just recently came out; I'd say see issue 605 if
>> roundup wasn't down.
>>> Build system part of the patch is OK.
>>> Diego

> Hi David,
> It looks like (from the investigation we've done on Red5) that Adobe
> always passed 16khz audio in the FLV under Flash Player 10.  It sends
> a audio-rate ID of "0" in that case, so you're save hardcoding
> avctx->sample_rate to 16000 if the codec is speex.  That should fix
> the ffmpeg -i problem.
> Patch attached.
> See here for background:
> http://jira.red5.org/confluence/display/codecs/Speex+Codec

It looks like the sample rate is now the only real issue with decoding  
Speex without a setup header, assuming the default mode is used for a  
given sample rate. I've reworked the decoding loop to not rely on  
knowing frames_per_packet so that issue is irrelevant with flv.

Also, stereo speex is now supported. As a side note, libspeex 1.0.5  
can encode stereo fine but completely fails at decoding it.

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