[FFmpeg-devel] pts/dts generation and index for mpegts (vob)

Michael Niedermayer michaelni
Sat Apr 25 14:31:12 CEST 2009

On Sat, Apr 25, 2009 at 02:18:13PM +0200, Erik Van Grunderbeeck wrote:
> Hello all;
> I have a couple of DVD's with wrapped around (2^31) pts in the streams.
> Wrapping occurs at various places in the vob files.

The most important thing to keep in mind is that mpeg allows timestamp
discontinuities and wraping is just one special case, any generic
solution for discontinuities, would also cover wraping thus any fix for
just wraping is wrong.

Also timestamp discontinuities are real not just theory, rests to 0
per chapter or even once every few seconds do occur in real streams out

and yes i can confirm neither seeking nor duration calc deals with this.
The easy fix to both is to assume approximate CBR and seek per byte.

Iam not aware of a 100% working solution to do exact seeking and duration
calls that isnt O(filelength). Though even that may be usefull to some
like video editors that need exact values even if theres a 30sec initial
delay (of course that would have to be optional)
and then seeking 10sec ahead or back from the current spot can
probably done reasonably exact and with reasonable speed ...

clean & seperate patches for all that are welcome
questions & disscussion is welcome too ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is not what we do, but why we do it that matters.
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