[FFmpeg-trac] #2952(undetermined:new): mjpeg: artefacts with 12bpp grayscale in low quality

[FFmpeg]

#2952: mjpeg: artefacts with 12bpp grayscale in low quality
-------------------------------------+-------------------------------------
               Reporter:  ami_stuff  |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:
                Version:             |  undetermined
  unspecified                        |               Keywords:
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 some artefacts (at the left side) are visible when quality of jpeg image
 is lower that 50%

 {{{
 knoppix at Microknoppix:/media/sdb1$ ffmpeg -i 30.jpg out.bmp
 ffmpeg version 2.0-bbcaf25 Copyright (c) 2000-2013 the FFmpeg developers
   built on Sep 12 2013 00:30:03 with gcc 4.7 (Debian 4.7.2-5)
   configuration: --disable-yasm --disable-ffprobe --disable-ffserver
 --enable-gpl
   libavutil      52. 43.100 / 52. 43.100
   libavcodec     55. 31.101 / 55. 31.101
   libavformat    55. 16.102 / 55. 16.102
   libavdevice    55.  3.100 / 55.  3.100
   libavfilter     3. 84.100 /  3. 84.100
   libswscale      2.  5.100 /  2.  5.100
   libswresample   0. 17.103 /  0. 17.103
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, image2, from '30.jpg':
   Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: mjpeg, gray16le(12 bpc), 1356x1588 [SAR 72:72 DAR
 339:397], 25 tbr, 25 tbn, 25 tbc
 Output #0, image2, to 'out.bmp':
   Metadata:
     encoder         : Lavf55.16.102
     Stream #0:0: Video: bmp, gray, 1356x1588 [SAR 1:1 DAR 339:397],
 q=2-31, 200 kb/s, 90k tbn, 25 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (mjpeg -> bmp)
 Press [q] to stop, [?] for help
 frame=    1 fps=0.0 q=-1.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
 video:2104kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.001021%
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2952>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker