[FFmpeg-trac] #7494(avcodec:new): Error concealment is broken for 422 content

[FFmpeg]

#7494: Error concealment is broken for 422 content
-------------------------------------+-------------------------------------
               Reporter:  cus        |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:  avcodec
                Version:  git-       |               Keywords:  ec
  master                             |  mpegvideo
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 Summary of the bug:

 Error concealment is broken on the chroma planes of a 4:2:2 mpeg2 video.
 It seems random data corrupts the chroma planes on the macroblocks which
 supposed to be corrected.

 See the uploaded file.

 How to reproduce:
 {{{
 ./ffplay out2.m2v
 ffplay version N-92178-gf099946faf Copyright (c) 2003-2018 the FFmpeg
 developers
   built with gcc 7 (SUSE Linux)
   configuration: --disable-vaapi --enable-vdpau --enable-gpl --enable-
 libfreetype --enable-libzvbi --enable-libass --enable-frei0r --enable-
 openssl --enable-nonfree --enable-libx264 --enable-libfdk-aac --enable-
 nonfree --enable-libvorbis --enable-decklink --enable-libmp3lame --enable-
 libvpx --enable-libsrt --assert-level=2
   libavutil      56. 19.101 / 56. 19.101
   libavcodec     58. 33.100 / 58. 33.100
   libavformat    58. 19.100 / 58. 19.100
   libavdevice    58.  4.105 / 58.  4.105
   libavfilter     7. 33.101 /  7. 33.101
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
   libpostproc    55.  2.100 / 55.  2.100
 Input #0, mpegvideo, from 'out2.m2v':B vq=    0KB sq=    0B f=0/0
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, progressive),
 640x480 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 1200k tbn, 50 tbc
 [mpeg2video @ 0x3ec06c0] skipped MB in I-frame at 29 9
 [mpeg2video @ 0x3ec06c0] Warning MVs not available
 [mpeg2video @ 0x3ec06c0] concealing 40 DC, 40 AC, 40 MV errors in I frame
    1.28 M-V:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0
 }}}

 If you turn off error concealment, output is much better:
 {{{
 ffplay -ec 0 out2.m2v
 }}}

 I also have real-world samples showing the same symptom, but I cannot
 share those publicly.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7494>
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