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I have an 8bpc .png sequence in RGB color space (full range 0-255 of course) that I need to convert to DNxHD bt709 "legal" range (16-235). Here is where I am so far:

ffmpeg -framerate 23.976 -i input_%04d.png -vcodec dnxhd -b:v 175M outfile.mov

This throws an error: pixel format is incompatible with DNxHD profile. I used to do this all the time in a earlier version of ffmeg with no issue... I assume it has to do with the color space, and in looking through the "colorspace" filter documentation I am uncertain what the proper command would be. As mentioned I do want to actually transform the values to bt709, legal range.

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ffmpeg -framerate 24000/1001 -i input_%04d.png -vf format=yuv422p10le -c:v dnxhd -b:v 180M output.mov
  • Use 24000/1001 or ntsc-film instead of the inaccurate 23.976 byname.
  • This encoder only supports the following pixel formats: yuv422p, yuv422p10le, yuv444p10le, gbrp10le. See ffmpeg -h encoder=dnxhd.
  • This encoder only supports specific combinations of bitrate, width, and height. See a list with ffmpeg -f lavfi -i nullsrc -c:v dnxhd -f null -.
  • bt709 should be automatically chosen, but verify it is what you want. See output of ffmpeg -i output.mov.
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  • Thanks for the info but when I tried setting the format to yuv422p10le I experience some color shifting, particularly in green, and when sampling the output in a few different applications it is not "clean" in that some values go above and below legal range. From what I've read online "colorspace" seems the best way to handle this I am just unsure of the syntax. – Spencer Oct 29 '19 at 20:38
  • Ok I did get this monster to work: colorspace=space=bt709:trc=bt709:primaries=bt709:range=tv:format-yuv422p:iall=bt601-6-625 however I am still above/below legal range in some of the channels. Possibly this is due to compression... Anyway my question is what the input characteristics should be? I chose bt610-6-625 arbitrarily, and when I scan my pngs with Exiftool the only metadata I get is "RGB" but not color space. Visually this looks ok, so maybe it is fine? – Spencer Oct 29 '19 at 20:55
  • PNGs typically are in sRGB colorspace - which has same primaries as bt709, but a different transfer function (gamma) and colorspace. – Gyan Oct 30 '19 at 6:04

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