Aye, that's definitely a video codec issue. For example, many 'puter movies are .avi (Audio-VIdeo) files or .mpg files, but the compression codecs when writing these files differs. It's generally a quality vs. filesize thing, meaning that the smaller the video the poorer video quality you'll get. In your case, Poser is rendering out at avery low-quality setting. If you're gonna composite footage later, render out to single TIFF's. That's one image file per frame. Are you using Poser 3, 4, or 5?