[FFmpeg-devel] Trouble with GSM audio.
Michel Bardiaux
mbardiaux
Tue Oct 2 15:40:27 CEST 2007
Artem Korneev a ?crit :
> Last weeks I spent in attempting to decode audio frames from GSM format
There aint no such animal. You probably mean GSM *codec*, in a wav, right?
> to PCM. But I still have no solution. :(
>
> I've initialize codec context by these lines:
>
> inCtx->bit_rate = 13000;
> inCtx->sample_rate = 8000;
> inCtx->channels = 1;
>
> and after that, decode buffer with GSM audio by this code:
>
> while ( in_size > 0 ) {
> outbuf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
> decoded_len = avcodec_decode_audio2(inCtx, samples_ptr,
> &outbuf_size, inbuf_ptr, in_size);
>
> in_size -= decoded_len;
> inbuf_ptr += decoded_len;
> samples_ptr += outbuf_size;
> }
>
> ..and only noise I have as result. :( Does anybody have a workable
> example of code for decoding GSM?
Yes: ffmpeg.c!
Please try ffmpeg -i on your input.
Chances are, its not GSM but GSM-MS. Is the codec_id right?
--
Michel Bardiaux
R&D Director
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