The xfade filter can create transitions between two inputs with various wipes and crossfades.

Examples

MP4 output

Fade between two images. Each image has a duration of 5 seconds. The fade duration is set to 1 second with the duration option, and it occurs at 4.5 seconds using the offset option.

ffmpeg -loop 1 -t 5 -i 1.png -loop 1 -t 5 -i 2.png -filter_complex "[0][1]xfade=transition=fade:duration=1:offset=4.5,format=yuv420p" output.mp4

GIF output

Using the split, palettegen, and paletteuse filters:

ffmpeg -loop 1 -t 5 -i 1.png -loop 1 -t 5 -i 2.png -filter_complex "[0][1]xfade=transition=fade:duration=1:offset=4.5,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" -loop 0 output.gif

Gallery

fade	fadeblack	fadewhite	distance
wipeleft	wiperight	wipeup	wipedown
slideleft	slideright	slideup	slidedown
smoothleft	smoothright	smoothup	smoothdown
circlecrop	rectcrop	radial