Just curious, where are you guys getting the 25 gig for one hour number? LD video is somewhere between VHS and DVD quality-wise, analog or not. Seems utterly pointless to use that much space on such a lousy source recording. Using that logic, it should require a 50 Gig file to fully preserve a 2 hour crappy analog VHS rip (or 150 Gig if it was recorded using EP mode
).
Have you read the link to Aaron Giles page at the very top of this thread? It spells it out pretty clearly. To paraphrase anyway:
"...pretty much all existing video compression algorithms are heavily patented.... Plus, [mame is about archiving the games and] MPEG hardly qualifies as “archival” quality.... The source material will be sampled at DVD resolutions (720×486 for NTSC video)... This is oversampling for laserdisc video, but it’s better to have more data than not enough data. This effectively gives you ... a total per-frame average of 705,726 bytes (5.4 MBits) per frame... or 70.9 GB/hour. [Our] lossless [method] tends to give you between 2:1 and 3:1 compression, [while our] lossy with medium deltas... gets you closer to 4:1 and 5:1 compression."
How they got 25:
70.9 GB/hr / 2.8 compression ~= 25 GB/hr, which is a "good enough" guess, I guess.
If they are really interested in preserving the original analog film sequences, they should use the recently created HD transfers from the original film cells (http://www.digitalleisure.com/contents/DVDRom_games.htm). Even those fit on a DVD, BTW.
Four problems: the image is better than the arcades, the format (mpeg2) is not open source enough to used in mame, the format is too lossy (both within a frame and between frames), and this is only limited number of LD games.