It's a naming convention. .m4v could be h.264, or it could be mpeg-4. It's pretty common to name DVD video (only) as .m2v. aka mpeg-2 video. .m2ts is mpeg-2 transport stream.
That being said, just because your file is named m4v, doesn't tell us anything about what it is. And I'm sure that once we know that technical piece of the puzzle, we could compare it with the specifications of the PS3 to see if there's a match. Having a match doesn't guarantee that it'll play it, but if it doesn't have a match, odds are good that it doesn't. With a match, you'll likely need to rename the file in either case. Or encode it into a container, which can sometimes be done without reconverting the video file itself. mplex can join .m2v and the audio only file into a DVD compatible video for example. And other means to an end.