[vdr] Re: cutting frame accurate in VDR?

["Dr. Werner Fink" <werner@suse.de>]

On Wed, Dec 04, 2002 at 01:50:55PM +0100, Jörg Knitter wrote:
> > > Hi Klaus,
> > >
> > > as you can see I still did not test the cut feature in VDR.
> > >
> > > Because I can move in an MPEG-Stream forward step by step (also remember
> > > e.g. Hardware/Software DVD players), I thought, something similar could
> > > be implemented: Rough cut by jumping through the I-frames, then
> > > frame-by-frame-forward decoding for setting the exact cut point.
> > > How this cut is finally done (reencoding, merging) is another story...
> > >
> > > Jörg
> > 
> > But you also want to be able to fine-position your cutting mark, and that
> > includes
> > (in most cases) being able to move it _backwards_ frame by frame, too.
> > 
> Yes, this would be VERY comfortable. But as I still have not seen any
> frame accurate MPEG cut tool, that also takes a look at the audio
> stream, it would already be a big step forward if you were at least able
> to jump back to the last I-frame - in the worst case, you have to press
> frame-forward 12 times again :-).
> Additionally, as private TV stations often use hard cuts between movies
> and trailers, you could define that the frame you currently see is not
> included in the cut file (cut point = current point-1 :-) ).

IMHO this would require to recalculate the time (delay) informations placed
in the PTS of the main audio/dolby frames.  In other words, the cut
offset from the previous I-frame to the current `cut' frame which can be
expressed as a time offset.  IMHO this offset should be recalculated and
added into the time coordinates found in the PTS of some of the audio/dolby
frames.  And this has to be done for _all_ audio/dolby frames afterwards
of the cutting mark.   This is my conclusion from the ISO/IEC 13818-1  ;^)



     Werner


-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe vdr" as subject.