When you insert a link with your video into a widget or to a background, you can customize the video output parameters, below you will see links to sources where you can get a detailed guide on how to use these parameters.
Reference
A complete list of all parameters for Youtube video can be found in the following article:
https://developers.google.com/youtube/player_parameters#Parameters
Reference
A complete list of all parameters for Vimeo video can be found in the following article:
https://vimeo.zendesk.com/hc/en-us/articles/360001494447-Using-Player-Parameters