I am using xfade with transition=custom, and trying to build expression. I am referring to official documentation https://ffmpeg.org/ffprobe-all.html#xfade
Per my understanding, expression should return pixel value of merged video
I built a few custom transitions using expressions that return some combination of A, B
For eg.,
"custom:expr='if(gt(P, abs(X/W - 0.5)), A, B)'"
"custom:expr='lerp(A, B, 1 - P)'"
For the next set of transitions, I want to fetch the pixel values from source, target video at specific positions, and combine them in my expressions
I tried using a0(X, Y), b0(X, Y) etc inside of
xfade=transition=custom:expr='r....
I ran into exceptions with ffmpeg complaining it doesn't understand the expression.
Can someone clarify, how i can fetch pixel values as specific position from source, target video and combine them in expression ?