[FFmpeg-devel] [PATCH] lavf: add a concat demuxer.

Michael Niedermayer michaelni at gmx.at
Tue Aug 28 18:09:38 CEST 2012


On Tue, Aug 28, 2012 at 10:20:52AM +0200, Nicolas George wrote:
> Le primidi 11 fructidor, an CCXX, Michael Niedermayer a écrit :
> > they can go from anything to anything but going from anything to
> > something close to 0 is more common 
> 
> There is probably an important distinction to make, still:
> 
> 1. When the discontinuity is caused by the timestamps overflowing the 33
>    bits allowed by the format, it will happen independently for each
>    streams.
> 
> 2. When the discontinuity is caused by different sources concatenated
>    together (like DVDs at chapter limits), it will happen at a precise point
>    in the file.
> 
> Case 1 is really different because MPEG-TS frequently muxes some streams
> ahead of others: you can have stream #0 that has already wrapped around and
> still a few frames of stream #1 with the old values. And it may even be more
> complex if there are B-frames. Still, I suppose you already knew all that.
> 
> 

> Still, I do not see any help that this concat demuxer could bring.

the concat demuxer will need to have logic to transform virtual
timestamps for seeking into per file timestamps + file
this is similar as to the case with discontinuities in a single file

or one could see the concat demuxer in a more generic way as a demuxer
that is able to play arbitrary "edit lists" that is
play t0..t1 of file f0 then t2..t3 of file f1

In this sense discontinuities would be part of it and it could also
maybe be used for mov/mp4 edit lists


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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