I did QA for two summers, on the FEAR games (then the 360 Port). Just be as descriptive as possible, know your way around computers/consoles, and don’t think you’re going to be playing video games all day. I spent 8 hours a day 5 days a week playing the same 3 levels of the game all day long. The only break we had was for Multiplayer. During the interview, stuff they asked me to do was basically Describe how to make a peanut butter sandwich as if somebody had no idea what one was, what bread is, anything. That’s the level of detail they want.
As far as video, I’m a programmer now, and if I got a bug submitted to me with just a video I’d bitch your lazy ass out. What am I looking at in the video? Whats the bug? What is the expected result versus the observed result? What level of the game are you in? What generic hallway #115 are you seeing the clipping at? Which one of the 30 enemies on screen is causing the framerate lag everytime they appear? You are making we watch a 5 minute video just to tell me that the radio at coordinates 100, 225, 3000 in level 5-2 is clipping into itself when looping?
Videos help complement your already descriptive bug reports, not as a substitute. When you have 10000 bugs on a project, watching a 1 minute video for each bug is way too much of a hassle when you can get a concise gist of the bug in 15 seconds from a well structured report.
You basically have to be cool with working long hours (during release time, you’ll be expected to work 16 hour days 6-7 days a week. You get overtime but you have no life or sleep during that time), boring days (stare at that wall for 4 hours and make sure the game doesn’t crash), crappy games (yeah you are testing for AAA titles but you never know), third rate treatment (Testers are the day labor of the game industry) and it will change your view on games forever.
But it’s really not a bad gig, it’s just an experience