Hi,
I use Premiere Pro 2 which cannot read mp4 files so I had to convert to avi using mp4cam2avi.
http://sourceforge.net/projects/mp4cam2avi/As far as I can tell the conversion is lossless as the information is just repackaged in a new "container". The new files work well in Premiere which is at its happiest when dealing with avi's. Rendering time is (I think) comparable to an avi created from my DV cam.
I know you said that you did not want to convert the files but it really does not take a great deal of time. The above software is free which is a bonus and I presume there is an equivalent for the Mac.
Cheers
Pat
I tried to use this software but ran into two issues.
One after conversion I can use windows movie maker but Pinnical Movie Studio 9 will not edit the file. Because the file is still a mpg 4 file just Divx according to GSpot.
Two I cannot get the audio to sync.