Wrong colours when decoding dnxhd

[Carl Eugen Hoyos]

​http://ffmpeg.org/pipermail/ffmpeg-user/2018-August/040775.html
A user provided a dnxhd file that looks ugly when decoded with FFmpeg and an rgb file that shows the expected output, I will attach two files.

$ ffmpeg -i Color_Profile_nuke11_DNxHD-mov64_444_Full.mov -qscale 2 out.avi
ffmpeg version N-91548-g481741e Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 6.4.0 (GCC)
  configuration: --enable-gpl --enable-gnutls --enable-libxml2
  libavutil      56. 18.102 / 56. 18.102
  libavcodec     58. 22.100 / 58. 22.100
  libavformat    58. 17.101 / 58. 17.101
  libavdevice    58.  4.101 / 58.  4.101
  libavfilter     7. 26.100 /  7. 26.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Color_Profile_nuke11_DNxHD-mov64_444_Full.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    uk.co.thefoundry.Application: Nuke
    uk.co.thefoundry.ApplicationVersion: 11.1v3
    uk.co.thefoundry.YCbCrMatrix: Rec 709
    uk.co.thefoundry.Colorspace: linear
    uk.co.thefoundry.Writer: mov64
  Duration: 00:00:00.04, start: 0.000000, bitrate: 352561 kb/s
    Stream #0:0(eng): Video: dnxhd (DNXHD) (AVdn / 0x6E645641), yuv444p10le(pc, bt709/unknown/unknown), 1920x1080, 352321 kb/s, SAR 1:1 DAR 16:9, 24 fps, 24 tbr, 2400 tbn, 2400 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : DNxHD
Please use -q:a or -q:v, -qscale is ambiguous
Stream mapping:
  Stream #0:0 -> #0:0 (dnxhd (native) -> mpeg4 (native))
Press [q] to stop, [?] for help
Output #0, avi, to 'out.avi':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    uk.co.thefoundry.Application: Nuke
    uk.co.thefoundry.ApplicationVersion: 11.1v3
    uk.co.thefoundry.YCbCrMatrix: Rec 709
    uk.co.thefoundry.Colorspace: linear
    uk.co.thefoundry.Writer: mov64
    ISFT            : Lavf58.17.101
    Stream #0:0(eng): Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 24 fps, 24 tbn, 24 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc58.22.100 mpeg4
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
frame=    1 fps=0.0 q=2.0 Lsize=      87kB time=00:00:00.04 bitrate=17080.2kbits/s speed=1.22x
video:81kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 6.957787%

[Balling]

The file on that link is correct: https://ffmpeg.org//pipermail/ffmpeg-user/2018-August/040775.html

The file here uses linear transfer and then some additional magic on top of it.