Set ProRes Color Space and Field Dominance in FFmpeg

This article provides a straightforward guide on how to configure color space and field dominance metadata in Apple ProRes MOV files using FFmpeg. You will learn how to set these parameters both during the video encoding process and when modifying metadata on an existing ProRes file without re-encoding.

Method 1: Setting Metadata During Encoding

When transcoding a video to ProRes, you can inject the correct color space and field dominance metadata directly into the output file by using FFmpeg's video tag and flag options.

Run the following command to encode a video to ProRes with HD color space (Rec. 709) and Top Field First (TFF) interlacing:

ffmpeg -i input.mp4 -c:v prores -profile:v 3 -pix_fmt yuv422p10le -colorspace bt709 -color_primaries bt709 -color_trc bt709 -field_order tt output.mov

Parameter Breakdown:

  • -c:v prores: Specifies the standard Apple ProRes encoder.
  • -profile:v 3: Sets the ProRes profile to ProRes HQ (use 0 for Proxy, 1 for LT, 2 for Standard, 3 for HQ).
  • -colorspace bt709: Sets the color matrix coefficients to Rec. 709.
  • -color_primaries bt709: Sets the color primaries to Rec. 709.
  • -color_trc bt709: Sets the transfer characteristics to Rec. 709.
  • -field_order tt: Sets the field dominance to Top Field First (use bb for Bottom Field First, or progressive for progressive scan).

Method 2: Modifying Metadata Without Re-encoding

If you already have a ProRes MOV file and want to change the color space or field dominance without wasting time and quality on a re-encode, you can use FFmpeg's prores_metadata bitstream filter.

Run the following command to update the metadata on an existing file:

ffmpeg -i input.mov -c:v copy -bsf:v prores_metadata=color_primaries=bt709:transfer_characteristics=bt709:matrix_coefficients=bt709:interlaced=1 output.mov

Parameter Breakdown:

  • -c:v copy: Copies the video stream without re-encoding, preserving the original quality.
  • -bsf:v prores_metadata: Calls the ProRes metadata bitstream filter.
  • color_primaries=bt709: Modifies the color primaries.
  • transfer_characteristics=bt709: Modifies the transfer curves.
  • matrix_coefficients=bt709: Modifies the color matrix.
  • interlaced=1: Sets the field dominance. Use 0 for progressive, 1 for Top Field First (TFF), and 2 for Bottom Field First (BFF).