I don't know if you can infect videos, but exe, zip, rar, iso, etc. files are easy to infect. Then the same file gets spammed so much times with different names causing you to see a lot of worm results. When you search for programs, click the size section so the largest file sizes will appear on the top. Never download files like 857.1 kb or something like that. Make sure the size makes sense and even then, before you open it, scan it.