[FFmpeg-devel] [PATCH] Minimal patch for raw G.729 demuxer

Vladimir Voroshilov voroshil at gmail.com
Sun Oct 30 03:40:49 CET 2011


Hi, Michael

2011/10/30 Michael Niedermayer <michaelni at gmx.at>:
> On Sun, Oct 30, 2011 at 02:43:55AM +0700, Vladimir Voroshilov wrote:
>> Hi , All
>>
>> Amit Dor-Shifer in "Encoding raw alaw to PCM"
>> (http://article.gmane.org/gmane.comp.video.ffmpeg.user/33365)
>> asked if ffmpeg able to decode raw g729 stream into some form of PCM
>>
>> Quick investigation shows that such decoding is not possible with
>> existing raw pcm demuxers due to lack
>> of proper g.729 initialization.
>>
>> Attached patch adds simple demuxer especially for g.729.
>> With this patch FFmpeg can decode provided sample using "ffmpeg -f
>> g729 -i test_123.sample test_123.wav" command line(or even "ffmpeg -i
>> test123.g729 test123.wav" after renaming sample file).
>> I've also added special option "bit_rate" for selecting between @8k
>> and @6.4k modes.
>>
>> Asking for review/comment.
>
> applied, thanks
>
> also, do you think this could be detected through a probe() instead of
> the file extension ?
>

Unfortunately, no. At least for this case.
G.729 specification (as well as implemented A and D annexes)  does not
define any headers or markers in pure data stream, AFAIK

> [...]
>
> --
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>
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>
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-- 
Vladimir Voroshilov     mailto:voroshil at gmail.com
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