[FFmpeg-devel] [PATCH] lavf/matroskadec: SMI to SVQ3

wm4 nfxjfg at googlemail.com
Wed Jan 6 10:41:19 CET 2016

On Wed, 6 Jan 2016 04:33:16 +0100
Mats Peterson <matsp888-at-yahoo.com at ffmpeg.org> wrote:

> At least in this case, MPlayer seems to look at the codec tag rather
> than the codec ID in order to determine the codec. Therefore, the
> 'fourcc' variable needs to be set to 'SVQ3' as well, which is later
> copied to st->codec->codec_tag in matroskadec.c.

You should fix mplayer instead. FFmpeg API users are not supposed to
use fourcc fields to identify codecs. The fourcc variable in
matroskadec.c is copied to AVCodecContext.codec_tag, which is not
necessarily a fourcc (depends on the CODEC_ID; most time it's unused),
and the svq3 decoder in libavcodec doesn't read it.

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