[FFmpeg-trac] #5264(swscale:new): GBRAP16 conversion artefacts

[FFmpeg]

#5264: GBRAP16 conversion artefacts
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               Reporter:  cehoyos     |                  Owner:
                   Type:  defect      |                 Status:  new
               Priority:  normal      |              Component:  swscale
                Version:  git-master  |               Keywords:  alpha
             Blocked By:              |               Blocking:
Reproduced by developer:  0           |  Analyzed by developer:  0
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 I will attach a GBRAP16 image that can be converted (correctly) into
 rgba64 png and yuv444p jpg. Conversion to (for example) yuvj420p and
 yuvj422p shows image corruption.
 {{{
 $ ffmpeg -i gbrap16.tif -pix_fmt yuvj420p out.jpg
 ffmpeg version N-78637-g7586b3a Copyright (c) 2000-2016 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      55. 18.100 / 55. 18.100
   libavcodec     57. 24.105 / 57. 24.105
   libavformat    57. 26.100 / 57. 26.100
   libavdevice    57.  0.101 / 57.  0.101
   libavfilter     6. 35.100 /  6. 35.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
 Input #0, tiff_pipe, from 'gbrap16.tif':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: tiff, gbrap16le, 480x270, 25 tbr, 25 tbn, 25 tbc
 [swscaler @ 0x2ed9700] deprecated pixel format used, make sure you did set
 range correctly
 Output #0, image2, to 'out.jpg':
   Metadata:
     encoder         : Lavf57.26.100
     Stream #0:0: Video: mjpeg, yuvj420p(pc), 480x270, q=2-31, 200 kb/s, 25
 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc57.24.105 mjpeg
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
 Stream mapping:
   Stream #0:0 -> #0:0 (tiff (native) -> mjpeg (native))
 Press [q] to stop, [?] for help
 frame=    1 fps=0.0 q=5.2 Lsize=N/A time=00:00:00.04 bitrate=N/A
 speed=2.27x
 video:26kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 }}}
 out.jpg looks ugly.

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Ticket URL: <https://trac.ffmpeg.org/ticket/5264>
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