how to fade two images with ffmpeg

Question

I have two images and I want to create a simple fading transition between them.

I also want the final output to be a sequence of images rather than a video? So if the fading transition was 10 frames long I'd want the output to be a sequence of 10 images.

How can I achieve this with ffmpeg?

Answer 1

See the blend video filter:

ffmpeg -loop 1 -i input0.png -loop 1 -i input1.png -filter_complex "[1:v][0:v]blend=all_expr='A*(if(gte(T,3),1,T/3))+B*(1-(if(gte(T,3),1,T/3)))'" -t 4 frames_%04d.png

This example will make a 3 second cross-fade of input1.png over input0.png.

To crossfade/dip-to-black multiple images see Create video with 5 images with fade-in/out effect in ffmpeg.