[FFmpeg-devel] Contract offer for implementing decoding functionality for interlaced AVCHD (5000 Euro + optional 1000 Euro Bonus)

Michael Niedermayer michaelni
Sun Jun 8 21:14:59 CEST 2008

On Sun, Jun 08, 2008 at 08:29:29PM +0200, Reimar D?ffinger wrote:
> Hello,
> On Sat, Jun 07, 2008 at 06:54:32PM +0200, Reimar D?ffinger wrote:
> > > What is needed to fix this is likely what robert marstons SOC2008 attempted
> > > as qualification task.
> > > See the ML, H.222 and H.264
> > 
> > I'll see if I can find time for it (I have not even looked at it yet)...
> Hmm... I wasn't able to find it, can you hint me better where to look?


see 2.7.5 Conditional coding of timestamps in H.222
It explains when timestamps can be omitted and hints at how one can
calculate the missing ones

> Btw. (and I think this was noticed by someone else before), just disabling the
> timestamp discontinuity checks "fixes" it, the problem I think is that
> pts is AV_NOPTS_VALUE for one of the fields (i.e. for every second
> packet).
> I attached the quick hack I used to test.

This is simply wrong, we have INCORRECT timestamps not just missing ones
at least with some videos. This needs fixing in libav*.

Please copy and paste the timestamps lavf outputs here if you think there
are just a few AV_NOPTS_VALUE in them.

> Greetings,
> Reimar D?ffinger
> P.S.: Just to make it clear, I'd be happy if someone else started
> looking into this and fixing it, I am not keen on it at all...

Iam even less keen on it, mainly because i know a truly correct fix will
be ugly and alot of work, simply because there are dozends of special
cases one needs to consider. But at the very first we need to ensure
that no incorrct timestamps are introduced and the the duration the
code uses matches reality.

You also might want to look at my alternative solution for mpeg2 field
pictures (some past svn revission)

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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