[FFmpeg-devel] [PATCH] Fix return value for incomplete H264 frame packets

[Pásztor Szilárd]

Carl Eugen Hoyos:
> Michael Niedermayer <michaelni <at> gmx.at> writes:
>> either way, iam not sure what actual problem people are trying to solve
>> with
>> this EAGAIN error code ?
> 
> Always the same problem;-)
> PAFF streams do not have correct A/V sync with MPlayer's native MPEG-2 TS
> demuxer (mpegts), and we can't make demuxer lavf the default because of
> FFmpeg

Actually it's a lot more than "not having correct A/V sync", because
what may seem sometimes correct A-V sync is only the sync algorithm
dragging the severely lagged video forward again and again, making
playback very jerky at best. Most samples are broken with both
demuxers.

The basic problem is that ATM there's no way to recognize if
no picture is returned because there's no data on purpose where
the player should wait a frametime, or because it's only a first
field where the second field should be decoded immediately.
Thus player applications can't keep sync because they don't have
enough information to do so.

> The provided sample (m2hd.ts) is not very useful, imo, the useful samples
> are
> still
samples/V-codecs/h264/sony-hdr-cx6-avchd-interlaced-decoding-problem
> (9
> seconds) and A-codecs/AAC/LATM/danish-1.m2t (new).

The m2hd.ts sample is useful in the sense that it has mixed parts
where both fields are in one packet and where they aren't. Both
mpegts and lavf demuxers fail miserably on this one.
I've made a patch for mplayer that fixes all of these issues with
both demuxers but the info seems vital from lavc.