Question: Is there a way to make ffmpeg's colorchannelmixer use perceptual gamma?
Background: I'm trying to salvage source H.264 video from a capture device (8mm film scanner) which seems to have an extreme saturation issue that often leaves the red and green channels saturated with minimal blue, leaving a bright yellow stain on that area of the frame. https://i.imgur.com/6Qh6PRk.png Editing a single frame capture of the video in GIMP, I see that if I use the Colours -> Components -> Channel Mixer tool and supplement the blue channel (1.0) with the green channel (1.0) https://i.imgur.com/Q0qqgSP.png the result is desaturated but usable https://i.imgur.com/t19QU4U.png I've attempted to replicate this using ffmpeg's colorchannelmixer with the same values (output blue = 1.0*blue + 1.0*green) Code: https://pastebin.com/raw/czS76ZrN but the result has a blue tint. https://i.imgur.com/TsnBKb2.png Looking at the RGB values, ffmpeg's behaviour is technically correct (the processed B channel is an exact sum of the source B and G channels), but GIMP's behaviour is what I need. GIMP's behaviour is described in https://graphicdesign.stackexchange.com/questions/136750/gimp-channel-mixer-does-not-work-as-expected and gamma correction is suggested as the likely difference in how GIMP reaches its result. Thanks, Simon _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
