[MPlayer-users] Problems with h.264 and lavf demuxer (paff/mbaff?)
munderl at tnt.uni-hannover.de
Thu Mar 6 12:38:01 CET 2014
> You should follow this.
> The check printing this was added recently, but shortly after it
> was noticed it causes such issues and I think it was reverted again.
> So I would think it shouldn't happen with latest FFmpeg, but if it
> does I think they need to fix it.
Latest git shows same behavior.
In my opinion, there are actually two problems:
First one is that neither the demuxer nor the h264 decoder skip undecodeable
frames until a valid SPS/PPS/IDR arrive but tries to conceal it. This
might be a useful feature for some broken streams / incomplete streams
and reduces latency in the case of seeking in unindexed files. But for the best
user experience I think it should be default to skip frames until the next IDR.
Second, and more serious problem is that the decoder gets so much confused
from the first additional B slice that it does not decode the following
PPS/SPS/IDR correctly but conceals all frames until the second IDR frame.
This yields, in my case, to 16 broken frames instead of just one.
You suggest to report this at the ffmpeg-devel mailing list? I'm not sure about
this as one gets easily flamed there for posting bug reports...
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