[FFmpeg-devel] [PATCH] H.264/AVCHD interlaced fixes

Michael Niedermayer michaelni
Sun Feb 8 17:30:37 CET 2009

On Sun, Feb 08, 2009 at 04:06:34PM +0100, Ivan Schreter wrote:
> Michael Niedermayer wrote:
> > On Sun, Feb 08, 2009 at 03:20:14PM +0100, Ivan Schreter wrote:
> >>>>> also it does not set the key_frame flag if there is no decode but just a
> >>>>> AVParser
> >>>>>   
> >>>>>       
> >>>>>           
> >>>> I don't quite understand what you mean. Parser is addressed by patch #6, 
> >>>> which handles both field combining and key frame flag. It was very hard to 
> >>>> split it in two patches, therefore I kept it in one.
> >>>>     
> >>>>         
> >>> i didnt review #6 as it was big & scary IIRC
> >>>   
> >>>       
> >> Umm... It is a little bigger, but not _that_ big. And it's pretty 
> >> straightforward - after finding a complete packet, this packet is parsed 
> >> via parse_nal_units(), which is nothing else but the code I got from 
> >> you, corrected and extended by a few things (namely reading field type 
> >> and frame number). In parser itself, it then looks if it's an unpaired 
> >> field picture, and if so, it will not return the packet yet, but note 
> >> down the position in buffer and relevant picture type info, wait for 
> >> next packet and pair it with it. As error handling, if an unpaired field 
> >> comes, it will be discarded, since it can't be combined anyway into a 
> >> full frame.
> >>
> >> I have commented the code IMHO quite extensively, so it should be easy 
> >> to understand.
> >>     
> >
> > the parsing and combining are seperate things requireing seperate
> > patches.
> >   
> Oh, c'mon! I have split the big patch as good as possible. But I don't 
> have infinitely much time, my small daughter was born a few days ago => 
> end of hacking. I'd like to have my patches in for the release, though.

you know that this h264 timestamp issue is one of the more obnoxious and
complex issues ...

More parsing code is likely not too hard to get into svn, the field combine
code may be very hard to get in. Basically i must awnser the question if
the alternative of treating fields seperately (which is what h264 wants)
is really hard enough to justify that we do that hack. And if that hack
wont bite us, i mean there are unpaired fields and such in the spec ...

also besides the point the parser may not drop fields that arent pairable

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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