As long as your are embedding video content (so your viewers can easily get back to the original source and your aren't copying, modifying and uploading someone else's content yourself, you can safely use sites like YouTube and Vimeo to bring in video clips to your project.
If you want to upload clips to Google Drive and embed them from there, make sure that they are your own uniquely created content or content that you have permission edit (ie "create derivative works"). Both YouTube and Vimeo allow you to filter down to videos that have Creative Commons licenses. Another place to look for this is: