Program for capturing iphone screen during video games execution

I was wondering how it is possible to capture what's shown in the iphone screen while playing a video game.

I know that this can be done and that there have to be special programs for this since there are many sites 开发者_运维百科out there that present a video review of iphone games.

Thanks for the help!

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My DisplayRecorder does just this. It requires you to jailbreak.