I'm currently editing a large volume of wildlife footage and plan to condense it into a 30 minute Blu-Ray DVD which I will use for lecturing to birdwatching and conservation groups. The footage was shot using a Canon XL-H1A. I am editing using Premiere Elements 4. I find the PC really slows up once I get beyond 5 minutes of a movie (the movie is complex and made up of 5-20 second portions of numerous 1-2 minute clips). The PC is so slow it becomes unuseable once the movie is much longer than that. I know more memory (currently 2GB) would help and also that rendering the movie in sections will also help.
My plan is to make the final movie in four minute mini movies; to save each mini movie as a new MPEG file, then as a new project assemble the mini movies into the final 30 minute movie to burn to Blu-Ray. My question is - what format should I used to save my four minute mini movies that will not lose quality ? Premiere Elements gives me to options of HD 1080i 25 or H.264 1080i 25, and I'm not sure which to use.