问题
I'm converting a PNG to JPG. The transparent background turns black by default. I need it to be white.
What is the FFmpeg command to set the alpha channel to a color?
I think it has something to do with the alphamerge and alphaextract Filters.
ffmpeg -i image.png -qscale:v 2 image.jpg
This replaces white with transparency when converting to png:
-vf chromakey=white
回答1:
You can use the geq filter.
ffmpeg -i in.png -vf format=yuva444p,geq='if(lte(alpha(X,Y),16),255,p(X,Y))':'if(lte(alpha(X,Y),16),128,p(X,Y))':'if(lte(alpha(X,Y),16),128,p(X,Y))' out.jpg
If your alpha is a pure black and white image, change 16 to 1.
来源：https://stackoverflow.com/questions/41346323/how-to-convert-png-transparent-background-to-jpg-white-background