Change video speed from 100% to 1000%?

[MJKUEIL]

[Selur]

Change the frame rate flag of the video from xy to xy*10.

ffmpeg -itsscale <slowdownfactor> -i input.mkv -c copy output.mkv

with slowdownfactor 0.1 you would get a 10x speedup.

[jagabo]

Your likely to have problems playing a video 10 times faster than normal. For example, playing a 25 fps video at 250 fps probably won't work because the player can't decode 250 frames every second. Decimating or blending frames and re-encoding is safer in such a case.\

If you have a very low frame rate video simply increasing the playback speed will work. For example, playing a 3 fps video at 30 fps will probably be ok.

[ProWo]

Consider to timelapse the video.
Can be done with clever Ffmpeg-GUI.