Saved Films
From Halopedia, the Halo wiki
Saved films is a confirmed feature in Halo 3. At the end of a campaign level or multiplayer match, you can decide if you want to save the film of that match, or you can delete it.
The maximum number of saved films is unknown but it is limited. Also, you can take screenshots from the saved films or detach the camera and float around to get different angles and views of the match.
