[vdr] Re: I-Frames and cutting

["Wiljo Heinen" <wiljo@offeryn.de>]

From: "Dr. Werner Fink" :

> >
> > If a GOP is not "closed" _and_ the "broken link" is set, then decoders
> > should not display the B- and P-frames preceding
> > the I-frame in time.
>
> In other words: the references between frames are given with the relative
> display time? No sequencial number or something similar?
>

I think I do not understand your question :-/ What references between frames
?

The whole point of this closed GOP/broken link thing is that in the
transmission/file the frames
are not necessarily appearing in display order.

Frames are marked with a "temporal offset" value that determines the display
order of the frames
in a GOP.

B-frames "refer" to a preceding P/I and a following P/I. "Preceding" and
"following" in the stream, not
regarding to display order. So a B-frame to be displayed after an I-frame
may occur before the
I-frame in the stream. Actually this is what happens "normally" in
DVB-transmissions. It makes life
of HW-encoders easier. But that way the B-frames refer to a P that is in the
last GOP. And it may not be
decoded properly if the preceding GOP is missing.

Hmm.... I wonder if I made myself clear :-/

rgds

  Wiljo




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