UPDATE: Activision requested the video pulled from YouTube.
Don’t be fooled by the video description, this has been making the rounds lately as “Leaked Video of Treyarch’s CoD4 Remastered” on PSVita.
This is simply a hacked PSVita using remote play to run older PS3 games. The game is being run on a PS3 with video output to a PSVita. There are several similar vids on YouTube with other PS3 games including Battlefield 3.