[FFmpeg-devel] Corrupted blocks and seeking issues in H264 disc sources
Andreas Öman
andreas
Sat Jul 14 10:22:58 CEST 2007
Hello,
infernix wrote:
> Hi,
>
> Andreas, perhaps this new sample can give you more insight as to what
> the problem is? If I find more blocks, I'll upload them and post a followup.
>
I've taken a quick look at it, and it seems the motion vectors
are somehow incorrect for the affected macro blocks. see [1]
and [2]. (Both frames have errors in the bottom left part of
the picture)
I've done some additional tracing on [1]:
[h264 @ 0x84b1de8]pic:11 mb:15/58
[h264 @ 0x84b1de8]mb_type = 0x1008, partition_count = 1, cbp = 0x0
[h264 @ 0x84b1de8]pred_motion match_count=3
[h264 @ 0x84b1de8]pred_motion ( 0 0 -2) ( 0 0 0) ( 0 8 -8) -> ( 0 0
-2) at 15 58 0 list 0
[h264 @ 0x84b1de8]final mv:198 102, cabac delta: 198 104
It would seem that the output from decode_cabac_mb_mvd() is
incorrect, but why (or if) it fails for this particular macroblock,
i'm not expert enough to tell.
[1] http://www.olebyn.nu/ffmpeg/issue4_mv_0076.png
[2] http://www.olebyn.nu/ffmpeg/issue5_mv_0050.png
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