It's only the modern equivalent of a flipbook, but every time that I want to create animations from a sequence of frames, I have to spend time rediscovering the method. This is the latest, which outputs a webm file - for the animations I've created, they seem to be lighter than gifs for equivalent quality. A few examples on the style transfer page.
If you stumble on this and know a better way, please let me know.
It assumes that the images are named frame001.png, frame002.png and so on.
png2yuv -I p -f 16 -b 1 -j frame%03d.png > intermediary.yuv vpxenc --codec=vp9 --best --cpu-used=0 --auto-alt-ref=1 --lag-in-frames=16 \ --end-usage=vbr --passes=2 --threads=4 --target-bitrate=7000 \ --fps=10000/1001 -o output.webm intermediary.yuv