What I'm doing is taking my video and using iMovie to edit it. There is no way to save the iMovie video back to the camera (either the HV 10 or the Canon HF 21S.) So, I save the completed movie to the USB drive. I have to change the exported file name to .mp4 extension first. Then I plug the USB drive into the Blu Ray player and play the video on my Samsung 55 inch TV. Works great. The only limitation I've found is, as I have said, the 4 gig limit on the USB drive. I have had to take most movies and process them in 2 parts to keep down the file size. Doesn't matter, because the Blu Ray player will automatically jump to the next file after it plays the first. Just have to name them so they will load in the correct order. When I said that I wasn't sure about reformatting the drive to Mac OS, I meant would the Samsung Blu Ray recognize and read the files if they were saved on the USB drive with that OS. It is important that everything will be compatible with the Samsung. That is why I could not save the .mov file to the USB drive. It will play the file if it has the .mp4 extension, but not the .mov. You do not have to change anything but the extension.