It seems that the answer has been covered, but here's my take on it. It's not the file, nor is it your CD-R drive. It's either the speed your CD drive plays back at, or the speed your machine reads the file. I've used RayDream for years (still do, from time to time, though I've ported over to Carrara for the most part), and have produced animations for our TV station ID. I always render out uncompressed frames, knowing full well that it will never play back at full video frame rate (30 or 29.97 fps) on a PC, unless it's rendered into a codec that the machine is designed to handle at that frame rate. But for the station ID stuff, I render it uncompressed and archive it on CD-R's. Then I can take the AVI (huge as it may be) into Premiere, AfterEffects, or over to the Mac for Media 100 or Final Cut Pro, do whatever editing and compositing I want to do, then run it out at full-motion NTSC video speed. Bluetone is right in that once you've compressed a video file, you can never go back. Hope that's helpful. - Dex