Question

If you look at the picture, the video function is gone. How do I recover again?

There should be a film UI next to the question mark, but there isn't

Answer 1

This could be because of two reasons :

1. Either your screen isn't big enough to accommodate all the icons on the toolbar.

2. Or, you have accidentally turned ON some customized layout which doesn't include the video track. to check this right click on the top toolbar, Select "Customize" and make sure, the layout is set to "Complete".