Phil, as Karl pointed out M2t files are compressed MPEG-2 in the camera. They are not further compressed during capture or editing in an NLE. All the codecs that Karl mentions (Cineform, uncompressed QT, HuffYUV, Apple Animation) are *less* compressed than M2t, taking load off the cpu during editing and playback. They don't improve the picture, but they usually help maintain the image through multiple generations of compositing or other renders.

Maybe, maybe not. If you're mastering for a compressed medium such as DVD or most web distribution, then yes, there will be compression out of your NLE, or possibly within another specialty compression program. If you're preparing for tape output there will typically not be further compression.

No, DV (DV25, the common prosumer standard) is a compressed standard too. Compression takes place in the camera at a ratio of about 3.5:1 (if memory serves)***edit - whoops, make that 5:1***. We talk about capture, but it is really more of a file transfer - the bits and bytes on the tape are transferred to hard drive. Most low-cost NLEs such as Final Cut Pro, Premiere, Vegas, Avid Xpress are optimized for editing DV25 natively, meaning that there is no further compression unless you choose to compress for distribution.

Not sure if anyone is still around for Ultra 2. I have imported a M2T (HDV) file and am finding that the audio is out of sync. Has anyone run into this problem ...perhaps have a fix for it?