[Ffmpeg-devel] Audio bitrate

[Michael Niedermayer]

Hi

On Mon, Nov 06, 2006 at 04:49:46PM +0100, Michel Bardiaux wrote:
> Seems wrong in some cases:
> 
> ffmpeg -i utc_1434.mpg -vn -acodec adpcm_ms -y -ar 8000 msadpcm.wav
> FFmpeg version SVN-r6917, Copyright (c) 2000-2006 Fabrice Bellard, et al.
>   configuration:
>   libavutil version: 49.0.2
>   libavcodec version: 51.24.0
>   libavformat version: 51.6.0
>   built on Nov  6 2006 16:13:12, gcc: 3.3.5 (Debian 1:3.3.5-13)
> Input #0, mpeg, from 'utc_1434.mpg':
>   Duration: 00:00:57.0, start: 92564.370489, bitrate: 668 kb/s
>   Stream #0.0[0x1e0]: Video: mpeg1video, yuv420p, 352x288, 104857 kb/s, 
> 25.00 fps(r)
>   Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, mono, 32 kb/s
> Output #0, wav, to 'msadpcm.wav':
>   Stream #0.0: Audio: adpcm_ms, 8000 Hz, mono, 64 kb/s
> Stream mapping:
>   Stream #0.1 -> #0.0
> Press [q] to stop encoding
> size=     235kB time=59.8 bitrate=  32.2kbits/s
> video:0kB audio:235kB global headers:0kB muxing overhead 0.018285%
> 
> Should be 32kbits in the 0.0 line.
> 
> With pcm_s16le, the bitrate is correct. But I dont see at once where it 
> is set. "Use the source, Luke", all right, but if somebody just *knows*...

ffmpeg.c audio_bit_rate default i guess
changing that of course wont help ...

you could try to set AVCodecContext.bitrate in adpcm.c to the correct value
but iam not sure if this is free of sideeffects

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
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