[FFmpeg-devel] [PATCH] MPEG-TS demuxer: Report 4cc in codec_tag field instead of SMTPE RID

Reimar Döffinger Reimar.Doeffinger
Mon Aug 31 19:15:28 CEST 2009

On Mon, Aug 31, 2009 at 09:18:29AM -0700, Baptiste Coudurier wrote:
> On 8/31/2009 1:27 AM, Reimar D?ffinger wrote:
> > On Mon, Aug 31, 2009 at 10:56:18AM +0300, Christian P. Schmidt wrote:
> >> I know that mpeg-ts streams to not support 4cc tags for the codecs.
> >> However, the mpeg-ts demuxer currently copies the registration ID into
> >> the codec's tag field, which in my opinion is worse than leaving the
> >> field empty.
> >>
> >> As an easy workaround the current tables for codec detection could be
> >> expanded to hold the 4cc codes as used in riff.c and return those in the
> >> codec_tag field.
> >>
> >> There are two codecs that do not have an official 4cc tag, namely
> >> bluray-pcm and E-AC-3. I'd go with mplayer's definitions for those, BPCM
> >> and EAC3.
> >
> > The codec_tag is not really supposed to be a fourcc, if there is no
> > stream-specific tag that (more or less uniquely) indicates the codec used
> > in the file it should be 0. Obviously it shouldn't be "random" nonsense
> > like it seems to be currently either though.
> Huh, it's not "random" nonsense, it's the registration descriptor if 
> present.

Well, with DVB-T receptions I know I got something else about each try
(sorry, haven't properly debugged it, nor recorded enough samples).
And HDMV for LPCM audio _and_ and some video codecs is not exactly a
"tag that (more or less uniquely) indicates the codec".
I don't mind much, but I am having some doubts that the thing that
currently ends up in codec_tag belongs there.

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