[FFmpeg-trac] #7176(avcodec:new): Resolution-related artefacts with clearvideo

[FFmpeg]

#7176: Resolution-related artefacts with clearvideo
--------------------------------------+---------------------------------
               Reporter:  cehoyos     |                  Owner:
                   Type:  defect      |                 Status:  new
               Priority:  normal      |              Component:  avcodec
                Version:  git-master  |               Keywords:  clv
             Blocked By:              |               Blocking:
Reproduced by developer:  0           |  Analyzed by developer:  0
--------------------------------------+---------------------------------
 Piotr kindly provided a new set of !RealMedia files with Clearvideo
 content that shows heavy artefacts with FFmpeg but not !RealPlayer.
 {{{
 $ ffmpeg -i bean2_324_500kbps_normal_encoding.rm -qscale 2 out.avi
 ffmpeg version N-90888-gad16423 Copyright (c) 2000-2018 the FFmpeg
 developers
   built with gcc 6.4.0 (GCC)
   configuration: --enable-gpl
   libavutil      56. 17.100 / 56. 17.100
   libavcodec     58. 19.100 / 58. 19.100
   libavformat    58. 13.100 / 58. 13.100
   libavdevice    58.  4.100 / 58.  4.100
   libavfilter     7. 21.100 /  7. 21.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
   libpostproc    55.  2.100 / 55.  2.100
 Input #0, rm, from 'bean2_324_500kbps_normal_encoding.rm':
   Metadata:
     title           : Title
     author          : Author
     copyright       : Copyrgiht
   Duration: 00:00:41.96, start: 0.000000, bitrate: 404 kb/s
     Stream #0:0: Video: clearvideo (CLV1 / 0x31564C43), yuv420p, 324x244,
 500 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
 Please use -q:a or -q:v, -qscale is ambiguous
 Stream mapping:
   Stream #0:0 -> #0:0 (clearvideo (native) -> mpeg4 (native))
 Press [q] to stop, [?] for help
 Output #0, avi, to 'out.avi':
   Metadata:
     INAM            : Title
     author          : Author
     ICOP            : Copyrgiht
     ISFT            : Lavf58.13.100
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 324x244,
 q=2-31, 200 kb/s, 15 fps, 15 tbn, 15 tbc
     Metadata:
       encoder         : Lavc58.19.100 mpeg4
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
 frame=  630 fps=0.0 q=2.0 Lsize=   16164kB time=00:00:42.00
 bitrate=3152.8kbits/s speed=81.4x
 video:16143kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.127851%
 }}}
 The output looks horribly broken, the issue is apparently related to the
 width, 320 works fine now.

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Ticket URL: <https://trac.ffmpeg.org/ticket/7176>
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