[FFmpeg-devel] G726 in Matroska

[Aurelien Jacobs]

On Tue, Sep 29, 2009 at 09:19:42PM +0400, Anatoliy Nenashev wrote:
> Hi!
> I found some problem in MKV format encoder (decoder).
> I try to encode some audio file in G726 and put it in MKV container:
> ffmpeg -i  in.wav -acodec g726 -ac 1 -ar 8000 -ab 40000 out.mkv
>
> After that I try to play this file with ffplay. I see the message:
>
> [matroska @ 0x1d58d90]Unknown/unsupported CodecID A_MS/ACM.
> [matroska @ 0x1d58d90]Could not find codec parameters (Audio: 0x0000,  
> 8000 Hz, mono, s16)
>
> GDB research show that audio  codec private data size in MKV file is 16.  
> But in the file I found the strings:
> } else if (!strcmp(track->codec_id, "A_MS/ACM")
>                   && track->codec_priv.size >= 18
>                   && track->codec_priv.data != NULL) {
>            init_put_byte(&b, track->codec_priv.data,  
> track->codec_priv.size,
>                          URL_RDONLY, NULL, NULL, NULL, NULL);
>            get_wav_header(&b, st->codec, track->codec_priv.size);
>            codec_id = st->codec->codec_id;
>            extradata_offset = 18;
>            track->codec_priv.size -= extradata_offset;
>        } else if (!strcmp(track->codec_id, "V_QUICKTIME")
>
>
> It means that ffplay can't obtain real codec_id because of  
> "track->codec_priv.size < 18 (=16)".

Thanks for the report. It should be fixed now.

Aurel