[Matroska-devel] last frame duration

wm4 nfxjfg at googlemail.com
Sat Feb 25 15:11:30 CET 2017


On Fri, 24 Feb 2017 20:44:17 +0100
Moritz Bunkus <moritz at bunkus.org> wrote:

> Hey,
> 
> > Could anyone help to check if the file is 100% spec-compliant ? If default
> > duration is 0, do I need to set last frame duration?  
> 
> Yes.
> 
> > or should it be calculated by whole duration - last frame position?  
> 
> No. The file duration is calculated from the frame timestamps &
> duration, not the other way around. Additionally, the file duration
> doesn't have to refer to a certain track at all; it can easily be the
> difference between the first audio frame's timestamp and the last
> subtitle frame's timestamp+duration if that is the biggest
> timestamp+duration in the file.

That's why proper per-track durations would probably be nice.

I know Haali circumvents this issue by probing the last video
timestamps (and mpv also has this, which can be enabled by an option),
but should it really be this way?


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