Hello all, I have a video that was filmed under bad lighting conditions, the background is too bright and people in the foreground are dark. I'm trying to use ffmpeg to correct it. Please kindly help me.
Here you can find a snippet: https://drive.google.com/drive/folders/1aG04znyHdDio7cvgaQlovYTb8bX8NTLL?usp=sharing video1.mts is the original file. video2.mp4 was created by a friend of mine using proprietary software on Windows. I've been trying to reproduce that. video3.mts is the best result I obtained (see below) but the contrast is still too high and the colors aren't quite right. I've tried several of ffmpeg's effects but maybe there are some better ones that I missed? - "eq=brightness=..." turns black into grey and gives the video a "foggy" look, no good - "colorlevels=..." I tried many parameter sets but couldn't do much better, in the end I concluded that probably linear scaling isn't good enough and I need nonlinear - "curves=..." was indeed better but when I stretched the curve beyond a certain point I obtained distorted colors - I tried "geq=..." too but it doesn't seem to work, I always get an error like this: ffmpeg -i video1.mts -vf geq='r=r(X,Y):g=g(X,Y):b=b(X,Y)' video3.mts [Parsed_geq_0 @ 0x55a01bb0aa60] [Eval @ 0x7ffd3d63afb0] Missing ')' or too many args in 'r(X' [AVFilterGraph @ 0x55a01bb09e80] Error initializing filter 'geq' with args 'r=r(X' Error opening filters! These are the commands that I used to produce video3.mts: ffmpeg -i video1.mts -vf colorlevels=romax=0.8:gomax=1.0:bomax=0.9 -b 12M temp.mts ffmpeg -i temp.mts -vf curves=r='0/0.05 0.1/0.25 1/0.8':g='0/0.05 0.1/0.25 1/0.8':b='0/0.05 0.1/0.25 1/0.8' -b 12M video3.mts Thanks Gerardo
