[FFmpeg-devel] [RFC] write standard stsd tags and objecttype for mp4/3gp

Michael Niedermayer michaelni
Mon Jan 28 14:18:42 CET 2008

On Mon, Jan 28, 2008 at 12:44:57PM +0100, Baptiste Coudurier wrote:
> Hi
> I had that in my tree since some time now anyway, and it will avoid
> other people wasting their time.
> This patch should do what's needed, except a few things:
> - stream copying mpeg-2 removes sequence header and puts it in extradata
> -> is the mpegvideo split function actually used ? Can mpeg2 be stored
> in any container without seq header ?
> -> -vglobal 4 makes it working but it still puts extradata, and then
> extradata is written in decodec specific tag, Im pretty sure this is
> should not be done.
> - set correct profiles for mpeg-2.
> One patch to move prefered object types to be be chosen first.
> One other patch to enable muxing.

also note, that as soon as you export the AVCodecTag tables from the muxer
the following code in ffmpeg.c should provide some slight protection against
the use of unsupported codec_tags with stream copy

    if(   !os->oformat->codec_tag
        || av_codec_get_id (os->oformat->codec_tag, icodec->codec_tag) > 0
        || av_codec_get_tag(os->oformat->codec_tag, icodec->codec_id) <= 0)
        codec->codec_tag = icodec->codec_tag;

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
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