Black box on bottom of videos?

[la tuta]

Started seeing a black box or something when watching videos on yt. Anyone know what this is and how to get rid of it?

 

[Stike96]

Started seeing a black box or something when watching videos on yt. Anyone know what this is and how to get rid of it?

Are you talking about your videos or someone else's. If it is yours you have to make sure that you are using the right resolution for Youtube (1280*720/1920*1080 etc.) and if you are using Premiere Pro or After Effects make sure that you are using square pixels (I think the option is available when you first start the program and go into settings, sorry if it is not exactly there eI don't have either program open at the moment)