Recording xbox 360 online games sf4?

I’m doing some searchs and i can see people who do this. Apparently you run the hdmi cable from the 360 to a DVR type device and then that device goes to your TV (at least i think that’s you do)

what type of device should i look for? I’d really like to do this i’ve seen some really nice HD quality videos on youtube that i’d like to do myself.

See this post.