Yesterday I filmed a very important interview on a rented jvc camera. The card I uses have worked before, but this time it made a new folder for each clip and they are all in .mp4 - I cannot see the when I want to play either in final cut, quicktimeplayer (error -12909) or if just keep them on the card. What is wrong? Please help me.
This camera has a couple of record set up options and can be set to record Quicktime files that can be dragged and dropped directly into FCP.
The camera may have been set to record Sony XDCAM with MPEG-4 wrapper. They should still open in Quicktime though and can be used in FCP.
Have you tried opening the files in MPEG Streamclip, you can download this free app from http://www.squared5.com it reads most formats and you can then convert your files to a useable format for FCP.
Is Quicktime telling you "This is not a movie file" in the error message?
It's a good idea if you're using rented equipment to test the gear before shooting. Especially these days when there are so many options in camera set ups. This maybe as simple shooting a couple of shots, downloading to a computer and checking the format, microphone / audio settings. that the camera isn't in some full auto mode and that it is actually recording pictures at all. This only takes a few minutes and if there is a problem it can be rectified.