[mythtv-commits] Ticket #8864: mythtranscode corrupting recordings when transcoding to MPEG4

[MythTV]

#8864: mythtranscode corrupting recordings when transcoding to MPEG4
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 Reporter:  nate <svndotmythtvdotorg1@…>           |            Type:  defect                
   Status:  new                                    |        Priority:  major                 
Milestone:  unknown                                |       Component:  MythTV - Mythtranscode
  Version:  Unspecified                            |        Severity:  medium                
 Keywords:                                         |   Ticket locked:  0                     
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 Have seen this behavior for about a week now.  Currently at r26104 on the
 trunk.

 When running mythtranscode on a HD recording using the "Low Quality"
 profile and MPEG4, I have had a number of corrupted recordings.  The
 output file sizes are approximately 1/3 of their normal size for typical
 recordings.  The audio appears fine, however all but a few sporadic frames
 of video are gone/corrupted.

 Note: Some of these recordings may have been tagged for transcoding twice,
 i.e. mythtranscode has been run on them twice with the same settings.
 When picking shows for transcode, I sometimes accidentally re-transcode
 recordings, however this has never caused any issues in the past and
 typically results in an innocuous no-op.  So this behavior might be
 specific to transcoding twice, I cannot tell for sure.

 Perhaps an option allowing myth to skip transcoding shows that have
 already been transcoded could be added (will check the tickets if a
 request for this has already been made)

 When playing one of the corrupted recordings, the frontend streams this
 output to the console:


 {{{

 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (70 left
 7FE828, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors
 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (70 left
 7FBFA7, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors
 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (70 left
 7F9267, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors
 2010-09-04 21:47:20.850 OSD: Base theme size: 1280x720
 2010-09-04 21:47:20.850 OSD: Scaling factors: 0.85625x0.972222
 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (70 left
 7F2829, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors
 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (72 left
 7F2187, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors
 2010-09-04 21:47:20.866 OSD: Base theme size: 1280x720
 2010-09-04 21:47:20.866 OSD: Scaling factors: 0.85625x0.972222
 [mpeg4 @ 0x70425c0] slice end not reached but screenspace end (66 left
 6E0072, score= -3)
 [mpeg4 @ 0x70425c0] concealing 3600 DC, 3600 AC, 3600 MV errors

 }}}

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Ticket URL: <http://svn.mythtv.org/trac/ticket/8864>
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