[vlc-devel] [PATCH] Discontinuities in source scr/pts/ dts break transcoding for dvdread -> mp4

Christopher Key cjk32 at cam.ac.uk
Sat Oct 17 19:55:44 CEST 2009

Rémi Denis-Courmont wrote:
> Christopher Key wrote:
>> Hello,
>> I recently ran into problems trying to transcode dvds to mp4 format.
>> Following any discontinuity in the scr (e.g. layer break, or skip over
>> unreadable sectors), I would lose the audio in the output.  What was
>> happening was that the discontinuity was causing the dts timestamps on
>> packets to jump backwards*.  As the muxer uses two fifos (audio and
>> video) and pulls in whichever of the packets has the lowest dts, a jump
>> back in time causes problems.  Imagine two FIFOs, with packets with the
>> following dts timeamps:
>> {...,6,4,2,98,96} and {...,5,3,1,99,97}
> Shouldn't this be fixed with a roll-over carry counter rather than by
> trying to autodetect discontinuities?
Sorry, I'm not quite sure what you mean by this.  Could you clarify.

Kind Regards,


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