[FFmpeg-devel] [Bugreport] and [Patch]: duration of TS streams is wrong when used near 2^33 wrap

Michael Niedermayer michaelni
Mon Oct 29 18:19:48 CET 2007


On Mon, Oct 29, 2007 at 05:36:57PM +0100, Thorsten Jordan wrote:
> Michael Niedermayer schrieb:
> > Hi
> > 
> > On Mon, Oct 29, 2007 at 04:52:52PM +0100, Thorsten Jordan wrote:
> >> Rich Felker schrieb:
> >>> On Mon, Oct 29, 2007 at 01:01:38PM +0100, Michael Niedermayer wrote:
> >>>>> I'm inclined to say that rather than trying to guess the unknown, we should
> >>>>> simply report the duration of these files as unknown.
> >>>> yes, fully agree
> >>> Me too. I'm inclined to always agree with this principle. Returning
> >>> guesses in fields documented as providing reliable information is very
> >>> bad.
> >> following that argumentation, the current implementation to compute
> >> duration would have to be removed too, because it is a guess as well, as
> >> Mans said. But who would want that?
> >> The proposed change wouldn't make the current situation much worse imho,
> >> but ok, it is your decision.
> > 
> > the change makes the code worse
> > as it turns negative durations (which would be ignored) into valid positive
> > ones, in practice such negative durations are more likely caused by
> > timestamp resets instead of 33bit wraping
> Sorry, but i doubt that this is the case. PTS wrap occurs every 26.5
> hours, but how often do PTS resets occur? 

IIRC i have a file where they occur every minute, while i never saw a dvd
with 26 hours length

> In fact i never saw one yet
> and i am working much with TS of TV broadcasts. They may happen, but
> surely less often than simple wraps.

i cant comment on broadcasts as i dont have the hardware to watch TS
broadcasts, but no matter what the timestamps for broadcasts are they
wont change the fact that for normal mpeg files this patch will break
things more than they are currently broken

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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