[FFmpeg-devel] [PATCH 1/3] mpegvideo_parser: implement parsing of the picture structure field

Jan Ekström jeebjp at gmail.com
Tue Feb 13 20:39:09 EET 2018

On Tue, Feb 13, 2018 at 2:13 PM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> ...
> If there are 2 fields in a packet that can be as 2 field pictures or
> as a interlaced frame coded in a way thats inseperable. Then you have
> 2 timestamps really and might have information associated with each
> field in principle. Our API doesnt have a place to put the information
> for the 2nd field anywhere. (which is together with picture_structure
> what i meant with needing a better API ...)

OK, so they are inseparable? Then it makes sense to pass them
together. Until now I only had the information that the two pictures
were in the same PES packet.

In that case the best thing we can do is set the field order correctly
for the set by parsing both field pictures' information. I just
wondered if the two field pictures are separately coded pictures, just
like with PAFF in AVC or how interlacing is generally done with HEVC
(which we even decode as separate fields right now).

Thus, I was just trying to query if the two field pictures were indeed
two separate images, and thus could be properly tagged and passed
through, without the latter picture apparently getting ignored. For
that at this point of time no new APIs would be needed, only work with
the parser.

> We have several decoders that can be fed with input at lower granularity
> like slices since a long time ago. So iam not sure how any "new APIs" are
> related here

Yes, although I think the feed/receive APIs make it work both ways
(you can feed more or receive more).


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