[FFmpeg-trac] #2606(avcodec:new): Artefacts decoding Hobbit 4k trailer

[FFmpeg]

#2606: Artefacts decoding Hobbit 4k trailer
--------------------------------------+---------------------------------
               Reporter:  cehoyos     |                  Owner:
                   Type:  defect      |                 Status:  new
               Priority:  normal      |              Component:  avcodec
                Version:  git-master  |               Keywords:  h264
             Blocked By:              |               Blocking:
Reproduced by developer:  0           |  Analyzed by developer:  0
--------------------------------------+---------------------------------
 As reported on [http://forum.doom9.org/showthread.php?t=167947 Doom9].
 I will upload 78 frames from the Hobbit 4k trailer which are decoded with
 artefacts that the reference decoder does not show. The first 32 frames, 4
 frames in the middle and the last frame (an IDR frame) are decoded bit-
 exact, the remaining frames are decoded differently than with the
 reference decoder.
 Decoding is different (but also incorrect) with multithreading.
 {{{
 $ ffmpeg -threads 1 -i hobbit4k-artefacts.h264 -f null -
 ffmpeg version N-53451-gd42106c Copyright (c) 2000-2013 the FFmpeg
 developers
   built on May 26 2013 14:59:18 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl --disable-indev=jack
   libavutil      52. 34.100 / 52. 34.100
   libavcodec     55. 12.100 / 55. 12.100
   libavformat    55.  7.100 / 55.  7.100
   libavdevice    55.  1.101 / 55.  1.101
   libavfilter     3. 70.100 /  3. 70.100
   libswscale      2.  3.100 /  2.  3.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, h264, from 'hobbit4k-artefacts.h264':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: h264 (High), yuv420p, 4096x2304, 23.98 fps, 23.98
 tbr, 1200k tbn, 47.95 tbc
 nb_threads: 0
 Output #0, null, to 'pipe:':
   Metadata:
     encoder         : Lavf55.7.100
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 4096x2304,
 q=2-31, 200 kb/s, 90k tbn, 23.98 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> rawvideo)
 Press [q] to stop, [?] for help
 [null @ 0x2f41c60] Encoder did not produce proper pts, making some up.
 left block unavailable for requested intra4x4 mode -1 at 0 127A
 [h264 @ 0x2f404e0] error while decoding MB 0 127
 [h264 @ 0x2f404e0] Cannot use next picture in error concealment
 [h264 @ 0x2f404e0] concealing 4401 DC, 4401 AC, 4401 MV errors in P frame
 [h264 @ 0x2f404e0] left block unavailable for requested intra mode at 0 89
 [h264 @ 0x2f404e0] error while decoding MB 0 89
 [h264 @ 0x2f404e0] Cannot use next picture in error concealment
 [h264 @ 0x2f404e0] concealing 14129 DC, 14129 AC, 14129 MV errors in P
 frame
 left block unavailable for requested intra mode at 0 80rate=N/A
 [h264 @ 0x2f404e0] error while decoding MB 0 80
 [h264 @ 0x2f404e0] Cannot use next picture in error concealment
 [h264 @ 0x2f404e0] concealing 16433 DC, 16433 AC, 16433 MV errors in P
 frame
 left block unavailable for requested intra mode at 0 79rate=N/A
 [h264 @ 0x2f404e0] error while decoding MB 0 79
 [h264 @ 0x2f404e0] Cannot use next picture in error concealment
 [h264 @ 0x2f404e0] concealing 16689 DC, 16689 AC, 16689 MV errors in P
 frame
 frame=   78 fps= 37 q=0.0 Lsize=N/A time=00:00:03.25 bitrate=N/A
 video:7kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.293803%
 }}}
 The original file contains additional three GOPs where decoding is not
 bitexact but no artefacts are visible, if this is a different issue, I
 will open a new ticket.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2606>
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