Jan Sloot claimed a compression factor of around 8x in his patents. The claim in the news article is "All movies ever made would fit on one CD-ROM", which is in

Jan Sloot claimed a compression factor of around 8x in his patents. The claim in the news article is "All movies ever made would fit on one CD-ROM", which is incorrect and misleading. "The keycodes to unlock all movies ever made would fit on one CD-ROM" would be correct and totally possible, just like all magnet links on the PirateBay probably fit on a single DVD. A block of 8x8 pixels, possibly with some filters, could easily repeat, say, a piece of the blue sky. Think of compressing three modern-day English books. Compressing each of them individually with their own table would likely result in a larger size than compressing the three books together with one big table. The compressor can make use of repetition of data across the three books to keep the file size smaller. You can test this with a good compressor. It's a principle that is used in normalized compression distance (comparing the length of individually compressed files, by the length of compressing their concatenation, to obtain a similarity metric).