Steve Mullen explains some of the problems exporting HDV footage (thus mpeg-2) from the timeline. Mpeg-2 records one I-frame and 6 to 15 B-frames (depending on the camera). I-frames keeps track of the B-frames by checking the changes of one frame to the next. When you bring your HDV footage into your NLE, new I-frames are created because cuts usually require one. When you export it back to HDV, it takes forever (as I found out recently). The two diagrams of the GOP strings of essentially before and after shots are vastly different. This is something that NLE's will be paying more attention in round two of HDV compatibility. If this interests you, I'd suggest reading the article.(via FresHDV)
