Want to extract out only alpha using ffmpeg

I want to extract alpha channel from the video using ffmpeg in which black will mean transparent and white will mean opaque

I used this:

But video output was a black screen. The command I used was :

ffmpeg -i 5.mov -vf "[0:v] format=rgba, split [T1], fifo, lutrgb=r=minval:g=minval:b=minval, [T2] overlay [out]; [T1] fifo, lutrgb=r=maxval:g=maxval:b=maxval [T2]" out.mov

1 Answer

Use this instead,

ffmpeg -i input.mov -vf alphaextract,format=yuv420p output.mov