Exported an SDR video from Descript, sourced from a Canon R6 Mark II with HDR PQ off. The same export shows materially different contrast in Descript, Quick Look, and QuickTime on macOS.

ffprobe reports:

codec_name=h264

pix_fmt=yuvj420p

color_space=bt709

color_transfer=iec61966-2-1

color_primaries=bt709

A lossless FFmpeg remux that changes only color_transfer from iec61966-2-1 (sRGB) to bt709 makes QuickTime/Quick Look render as intended:

ffmpeg -i input.mp4 -map 0 -c copy \

-color_primaries bt709 -color_trc bt709 -colorspace bt709 \

-movflags +faststart+write_colr output.mp4

Could you verify whether Descript is writing an sRGB transfer tag for video whose pixel values are intended to be Rec.709, and ensure exported SDR MP4s contain internally consistent color metadata?

MacOs 26.6.2

Descript 2.21.1