Instructions
Insert the SD card into the memory slot reader. The memory card reader is found on the front of the console under a hatch that you can lift.
Power on your PS3 and navigate to the "Videos" tab in the Xross Media Bar.
Highlight the SD card, press "Triangle" and select "Display All." This will display all of the video content stored on the memory card.
Select your video and press "X" to play.