[vlc-devel] issue arising from OggDirac muxing

[David Flynn]

On 2008-10-28, Laurent Aimar <fenrir at via.ecp.fr> wrote:
>  That is an error of the ogg muxer, it should not be done independantly
>  The proper fix would be to use the lowest DTS over all ES IF ogg allows it.

Actually, i take that back; it does do it correctly, (I was running it without
audio, and the rest of this post describes what that is)

The actual problem is if there is no audio, and if it were to be muxed
in with a command line tool later (or even vlc, later).  So vlc will
generate the following oggdirac file:

VideoDT: [0, 1, 2, 3, 4, 5 ...]
VideoPT: [6, 1, 2, 3, 4, 5 ...]

(Note the absence of any video at time PT==0)

If you were to try to mux it with an audio file (which was supposed to
be coincident in time):

AudioPT: [0, 1, 2, 3, 4, 5 ...]

You end up with:

VideoDT: [0, 1, 2, 3, 4, 5 ...]
VideoPT: [6, 1, 2, 3, 4, 5 ...]
AudioPT: [0, 1, 2, 3, 4, 5 ...]

Note that when AudioPT = 0, the corresponding correct videoPT=1.  (Since
the -ve offset has been lost).

It might be possible to solve with OggSkeleton, but thats far too vague
to even consider.

So, is this something VLC should care about?

..david