[FFmpeg-devel] [PATCH] Tell calling application about PAFF fields

Thorsten Jordan tjordan
Tue Oct 9 17:04:44 CEST 2007

Jeff Downs schrieb:
> On Sat, 6 Oct 2007, Carl Eugen Hoyos wrote:
>> Hi!
>> I tested the PAFF patch with mplayer, and it works well, but A/V sync
>> breaks because frame rate has to be doubled for PAFF fields.
>> Attached patch is a possibility to solve this problem, please comment.
>> Carl Eugen
> I was thinking on this as well. I'm guessing mplayer's problem is that the 
> demux/parser only pushes out a field, so it delivers x fields / second 
> instead of x frames / second?
> Another place to potentially fix it is in the 264 parser, making it output 
> frames and field pairs instead of frames and fields.  The docs for the 
> parser interface aren't clear on which behavior is more correct.
> And, you'd still have to deal with unmatched fields (ones that have no 
> pair of opposite parity). 

well here is my opinion as "user" of avcodec, just my 2?.
i'd suggest the latter, let the parser always output field pairs, because
- other decoders do it as well ;-) that is coreavc and also libmpeg2
(here for mpeg2 fields).
- there can be frames and fields in one stream in repeating mix, it
would be simpler for users to always use avcodec_decode_video and decide
by AVFrame->interlaced wether its fields or frames

and btw., congratulations to Jeff, Martin, Carl Eugen, Andreas and
Michael for making ffmpeg even better by implementing/integrating PAFF.

Greetings, Thorsten

More information about the ffmpeg-devel mailing list