ffmpeg - Video - Speed Up

ffmpeg -i input.mp4 -an -filter:v "setpts=0.1*PTS" output.mp4

NOTE:

0.1 accelerates x10 by dropping frames, 0.01 would accelerate x100 and so on.
-an removes audio.

Use a complex filter to speed up video

ffmpeg -i input.mkv -filter_complex "[0:v]setpts=<1/x>*PTS[v];[0:a]atempo=<x>[a]" -map "[v]" -map "[a]" output.mkv

NOTE: w/ audio, where <x> is the speedup ratio.

For example, to speed up the video by 1.5 times the original speed, use:

ffmpeg -i input.mkv -filter_complex "[0:v]setpts=0.6667*PTS[v];[0:a]atempo=1.5[a]" -map "[v]" -map "[a]" output.mkv