[vdr] Re: cutting frame accurate in VDR?

[Jörg Knitter <joerg.knitter@gmx.de>]

> > > I know, how to convert a GOP into all I-frames: By reencoding the
GOPs
> > > where the cuts occur.
> > >
> > > Setting only I-frames btw. is a bad solution, as it requires a lot
of
> > > unnecessary bandwith. You can simply use a shorter GOP
> > > instead as a GOP
> > > does not have to have a fixed size. Example (| marks the cut
point):
> > > Before: ...IBPBBPBBPBBP IBPBB|... {commercial break} ...|PBBP
> > > IBPBBPBBPBBP...
> > > After:  ...IBPBBPBBPBBP IBPBP     {no more break :-)}    IBBP
> > > IBPBBPBBPBBP...
> > > where IBPBP and IBBP are reencoded.
> > >
> > > But as I mentioned before: How to sync the audio?
> >
> > Is there any need to sync audio.
> > Actually you just need to replace at most two frames.
> >
> > At the a start of the new stream we need to replace the B- or
P-frame
> with an I-frame and at the End of the new stream we only need to
replace
> the last frame if it's a B-frame, as P-frames don't need to now
anything
> about follwing frames.
> >
> > If you want to optimize this you don't even need to replace the last
B-
> frame if you provide the next I-frame on which the B-frame is
dependend on.
> But this may result in strange behaviour when replaying the end.
> >
> > CU,
> > Christian.
> 
> If you want to do frame accurate cutting you *must* convert the entire
GOP
> into
> a sequence of I-frames, because that's the only way you can arbtrarily
> position
> a cutting mark and display each individual frame.
> 
> Klaus
> --

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




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