Video display problems

I am designing a theme and found two problems that I have no idea how to fix. First is:
I downloaded and imported the test posts. everything is displaying okay, but The video embedding with the code such as ‘[youtube]video[/youtube]’
does not show the videos
Second problem is that when I add a video to the sidebar with a widget the video breaks out of the sidebar. https://detoam.com/sidebarvideo.png
How can I fix those issues? thanks.