I recently ripped a DVD using the Handbrake software, which created a 20-gig m4v video file. Strangely though, the file doesn't want to open in any of the applications i've tried: iTunes, Compressor, Final Cut Pro, Avid MC...nothin'. Anyone have any ideas as to why this is so?
What settings did you use for going tot he m4v? Very strange that a DVD (maximum of about 4.3GB) would result in a file 5 times that size. So sounds like some of your settings weren't right.
An m4v file should end up being about half the size of the .vob file on a DVD even if you use the same data rate (roughly 4-6Mb/sec). H.264's value is that it produces visual quality similar to MPEG2 at about half the data rate.