Do video assets have to have "closed GOP"?

have a post a little further down, but basically DVD SP2 crashes whenever I try to build. Did some troubleshooting, and noticed that whenever I use only video assets that have a closed GOP it builds OK, but when i use some video assets that don't have closed GOP it crashes when i try to build. Is that a coincidence or are non closed GOP clips problematic? and is there something in compressor that can give a clip a closed GOP?

Thanks for any help - Chris

thanks for the info. once I changed all my video to closed GOP it built fine. what happened is that in Compressor if you change the setting from Automatic to NTSC, for some reason it quietly changes your GOP to open. didn't notice that till today. of course according to the manual you can mix open and closed GOP structures, unless you're doing mixed-angle stuff, but that definitely doesn't work on my computer, and i'm curious if it's just a glitch on my system, or if it's a glitch in DVDSP2. can anyone else run a test and see if you can mix open and closed GOP? might want to let apple know if it's a repeatable glitch.

Also, if I'm doing a short film and quality is more important than file size, should I do IBP and a small GOP of 6? Wouldn't that give me more I frames, less B-frames, and thus better quality?

Thanks a lot - chris

Open GOPs are a method of squeezing a little more quality out of low bit rates but there are just too many problems that seem to pop up with using them. Given the chance to choose I would never recommend using them (open GOP).