[FFmpeg-devel] [RFC/PATCH] matroska timestamps not always pts

[Rich Felker]

On Tue, Nov 20, 2007 at 11:50:32PM +0100, elupus wrote:
> "Uoti Urpala" <uoti.urpala at pp1.inet.fi> wrote in message 
> news:1195598562.18396.9.camel at symbol.nonexistent.invalid...
> > On Sun, 2007-11-18 at 23:11 +0100, elupus wrote:
> >> Apperently the timestamps stored in matroska container can mean different
> >> things. For native tracks they normally mean pts, while for others this
> >> isn't always the case.
> >>
> >> The case i'm trying to nail here is the ms compatibility case. In this 
> >> case,
> >> timestamps should correspond to the frame numbers in avi. This patch 
> >> makes
> >> demuxer only set the correct timestamp (dts/pts) in the packet.
> >
> > Does some spec say they "should correspond" to frame numbers? Or are you
> > only saying this because you've seen (invalid?) files generated by
> > someone which do this?
> 
> 
> Well, i didn't get that exact wording from Haali, what I got was that 
> "timestamps should be treated as timestamps are treated in avi." And since 
> there is no such thing as timestamps in avi, the closes thing you got is 
> frame number. (hmm or is it packet number in stream perhaps, don't remember 
> how vfr files in avi are encoded) .

AVI has 'timestamps' in the form of dts implicit from the position of
the frame in the file and the timebase in the header. Are you saying
Matroska timestamps should be treated as dts-in-timebase rather than
as pts for the MS/FOURCC case?? This sounds rather stupid, but perhaps
the design is that bad...

Rich