multiply should result in a darker image according to this website. However every multiply
options with input that I'm using resulted in darker green videos instead of layering it with colour that I use for layering.
Many people refer that as format issue and resolved by using format=rgba
options, however in my case there I'm still stuck.
FFMPEG command :
ffmpeg -i red.jpg -i car.mp4 -y -filter_complex [0][1]scale2ref[a][b];[a]setdar=1/1[c];[b]setdar=1/1[d];[c][d]blend=all_mode=multiply:all_opacity=1[out];[out]eq=contrast=2:brightness=0.5[ckv] -map [ckv] output.mp4
with format=rgba
ffmpeg -i red.jpg -i car.mp4 -y -filter_complex [0][1]scale2ref[a][b];[a]setdar=1/1[c];[b]setdar=1/1,format=rgba[d];[c][d]blend=all_mode=multiply:all_opacity=1[out];[out]eq=contrast=2:brightness=0.5[ckv] -map [ckv] output.mp4
assets in case someone want to try it. - Images - Videos
FFMPEG version 4.1