[FFmpeg-devel] Matroska demuxer gives presentation order in dts

Michael Niedermayer michaelni
Wed Feb 27 18:40:41 CET 2008

On Wed, Feb 27, 2008 at 01:06:55PM +0000, elupus wrote:
> Thorsten Jordan <tjordan <at> macrosystem.de> writes:
> > 
> > Hello,
> > 
> > i just stumbled over some strange behaviour when reading Matroska files,
> > the reported pts are in expected presentation order (non-monotonous),
> > but the dts values of the packet are as well!
> > 
> > Beside that the Matroska demuxer reports several issues with that file, like
> > Ignoring seekhead entry for ID=0x1549a966
> > (many)
> > Unknown entry 0x73a4 in info header
> > Unknown track header entry 0x55aa - ignoring
> > (several)
> > Unknown attachedfile ID 0x46ae
> > 
> > Is there interest in this file? can one just cut 10mb off the start of a
> >  mkv file and it still is useable? Original is nearly 100mb in size.
> > 
> > I am much more interested in the dts problem though...
> > 
> Yea i've reported this before. The matroska demuxer only fills in pts values, 
> then lavf copies this value to dts if it's missing. Normally this should be 
> done almost correctly if there exists a parser for the video that marks up B 
> frames correctly, but that isn't always the case.
> I tried to talk michael into not entering dts values at all if demuxer 
> couldn't generate them, but got no interest in that.

DTS are not optional, they are needed for remuxing to a different container.
Thus not setting them at all is not a solution.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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