Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: Thenasty on December 06, 2006, 08:23:01 am
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Laserdisc support is coming (here) ;D
http://www.aarongiles.com/
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What's taken so long?
I used to know the answer to this question but it's been quite a while since I was up on it. Wasn't it because the LD players couldn't truly be emulated or was it just that it hasn't been long enough since they've been out (or something else)?
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Is there going to be any advantage over using Daphne (www.daphne-emu.com)? Most of the mamedevs aren't really too concerned about game playability, so I would be surprised if it ends up any better than what Daphne has had running for years.
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I think the mamedevs are going for arcade accuracy.
Daphne VLPD is jiggery pokery, smoke & mirrors, mpeg2.
It works very well, and nice to have instead of the laserdisc player, but also nice to have when all you have is the laserdisc and player and no boardset. Daphne is more flexible in that department.
With a 20 to 1 ratio compared to Daphne's mpeg solution I think you will find Mame's version a little daunting for chd space. How does 25 gig a game sound? DVD-HD anyone? ;D
The quality will be there.
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...at 25GB for MAME DL, I will stick with my 3GB Daphne setup. As for visual quality...I am running it on a 26 year old Electrohome standard resolution monitor...I doubt there would be a noticable difference from the MPEG version from the 25GB version.
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I think the mamedevs are going for arcade accuracy.
Daphne VLPD is jiggery pokery, smoke & mirrors, mpeg2.
It works very well, and nice to have instead of the laserdisc player, but also nice to have when all you have is the laserdisc and player and no boardset. Daphne is more flexible in that department.
With a 20 to 1 ratio compared to Daphne's mpeg solution I think you will find Mame's version a little daunting for chd space. How does 25 gig a game sound? DVD-HD anyone? ;D
The quality will be there.
I would think DVD quality compression (mpeg-2) would be more than sufficient for laserdisc video. The 1.5 Gig DL rips I've seen look beautiful on a low res display device (TV). I guess I don't see the point of a 25 gig video file using custom compression unless it's going to be an HD rip (which wouldn't be arcade accurate).
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I think the theory here is oversampling. The source (LD) is analogue, so in theory its impossible to perfectly reproduce it. In a few years, 25gig will be a pen drive (or less) - so why skimp on quality now?
(Not necessarily my views, but rather the approach being taken)
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A laserdisc isn't analog....
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They actually are analog believe it or not:
http://www.access-one.com/rjn/laser/legacy/ld96.html
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...yes...they are analog.
And being analog no two REAL LEGITIMATE DL disc is exactly alike so the argument is moot.
That said, I am not saying that the mame team shouldn't emulate DL...I am saying that for me, personally, I see no benefit.
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hmm interesting. So then how can the mame devs properly emulate it? Wouldn't it be like emulating pong?
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Sounds really cool and all, and I hope Aaron can pull it off.
I got Daphne working in my cab just perfect with DL, DLII, Space Ace, Cliff Hanger, and a couple of others.
I will certainly try the LD Mame when it is finished, though.
Good luck Aaron!
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From what I understand, a 1 hour LD is about 25 gigs, mos of the Arcade LD's are only about 20 min.
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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 :P).
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.
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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 :P).
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.