DVDs play too fast, with a green border...?

Hi,

I am having a problem with DVDs that I have compressed using the standard settings in Compressor (Best quality DVD 90 mins into mpeg2 and .ac3 audio).

Besides getting the same regularly documented problems with faint green borders on the sides of the image, I've also found that when I play the disks on an iMac, the image looks like it's playing back slightly too quickly. The audio stays in sync, but the video is definitely running slightly too quickly - human movement and speech looks unnatural.

On all other systems i've tried - Macbooks, PC hardware and DVD players, this isn't an issue, but it is consistent across all of the iMacs that I've tested my DVD on.

Does anyone have any thoughts as to what might be causing this...?

Thanks for taking the time to read and respond.

Jon