After a bit more testing I realised my above solution didn't work for files with different frame rates, so here's this: vlc -vv 1.mp4 input.mkv --sout "#transcode{vcodec=H264,venc{profile=veryfast,level=40},vfilter=canvas{width=1280,height=720,aspect=16:9},width=1280,height=720,fps=25,vb=1000,a...