Yes, you can submit Videos (Whether from Youtube or other platforms), voice, and even images as prior art for an invention.
As @patentico mentioned that providing the hard copy of a video is a bad idea as you may face difficulties in providing publication date of that video. You may need to collect evidence of original publication date of the same.
Also, a video will be considered prior art even if the source of that video and patent are same (if the time frame between the publication date of video and filing date of the patent is more than a considerable time provided by local IP laws).
As your request, I have found one infamous patent case of Apple where their patent was invalidated by using a video as Prior art. The interesting fact about that case is, the video considered as prior art was Apple's own keynote video on iPhone release presented by Steve Jobs.
Iphone's Rubber-banding effect patent was invalidated in Germany after Google submitted Steve Jobs' presented keynote video as prior art. The court even rejected various amended claims by Apple. Only 3 out of 20 claims were granted.
While searching for cases, I found an article with 4 such patent disputes where visual content was considered as prior art (including the above case I mentioned).
Not just a YouTube video but, a comic, picture, or even Movie can be used a prior art as long as you're able to provide strong relation with the invention and publication date of the same.
Here are the other 3 patent cases including one where a movie from 1968 was considered as prior art for Apple's iPad design.
4 cases where examiner found ridiculously awesome prior art.