Uploaded version QTs are looking lifted

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Hello,

I am submitting shots to a client by adding a new version to a shot and uploading a DNxHD quicktime file. The client has complained that some shots are looking washed out. I checked the videos and sure enough, it looks lifted compared to what I have in my local drive. It isn’t happening to all DNxHD videos I upload though. For the same shot that had the colourspace lifted, I uploaded an H264 and it was fine. I have noticed that the shots that get lifted are only the ones that were made in Nuke (as opposed to my other shots that were made with Adobe media encoder), but again, not all the Nuke video files are getting lifted - only a few.

Do you know why Shotgun is changing the colourspace of my videos for only some files?
Thanks!
Caroline

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Under the hood, Shotgun uses FFMpeg to do essentially the same as Adobe Media Converter, except it does a good job.

The downside is that there’s a million parameters to tweak.

The Shotgun team currently have hardwired a limited set of parameters to the movie uploading code, so you’ll have to be a little more consistent with what you’re feeding it. There’s metadata in the DnXHD files and no doubt it’s triggering the differences.

You might like to investigate using the command line tool ffmpeg to filter all your uploaded videos.

You can use the sister tool ffprobe to get info about your files; here’s an example:

$ ffprobe dnxhd_test.mov

Input #0, mov,mp4,m4a,3gp,3g2,mj2:
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    uk.co.thefoundry.Application: Nuke
    uk.co.thefoundry.ApplicationVersion: 11.3v4
    uk.co.thefoundry.YCbCrMatrix: Rec 709
    uk.co.thefoundry.Colorspace: rec709
    uk.co.thefoundry.Writer: mov64
  Duration: 00:00:01.00, start: 0.000000, bitrate: 352332 kb/s
    Stream #0:0(eng): Video: dnxhd (DNXHD) (AVdn / 0x6E645641), 
      yuv444p10le(tv, 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

More here, for the morbidly curious: https://trac.ffmpeg.org/wiki/colorspace

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