How to change the playback speed of a YouTube video. YouTube gives users the option to modify the playback speed of some videos. This is particularly useful in the case of videos that you are obligated to watch (training videos, terrible fan videos, the occasional conference talk, etc.) and want to get through quickly. You have the option to speed a video to one-and-a-half times normal speed and double normal speed. You can also slow a video to half speed or quarter speed, which can be handy when trying to draw out a training-over-lunch session.