[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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