What's the difference between an AVI file and a MPEG-1 file?

Since the AVI format is uncompressed, one hour of video data with 352 x 288 resolution AVI file will occupy up to 33 GB disk spaces, which is beyond the storage power of ordinary computers. PowerVCR II can directly record video images in MPEG-1 format. The same one-hour of content with a 352 x 288 resolution video content just takes up 650 MB space.