>Ian Smallshire (@IanSmallshire) Tweeted: ld-decode and Domesday duplicator does wonders for Dragons Lair Laserdisc
I am guessing that example is after using ld-decode rev6 version after Simon and crew released that version weeks earlier. https://twitter.com/simoninns
And for those that didn't see this post and thread from the previous week.
Very nice to see work going on with laserdiscs. Has the main laserdisc players been emulated for Dragon's Lair Space Ace ect. as I know some laserdisc games are emulated in MAME but not sure if they was the pcb versions of them or even if there was pcb versions of them. Also they got new old stock laserdiscs what great finds.
>Has the main laserdisc players been emulated for Dragon's Lair Space Ace ect. as I know >some laserdisc games are emulated in MAME but not sure if they was the pcb versions of them >or even if there was pcb versions of them.
And fortunately the roms from the pcbs are already dumped.
As for laser disc player systems being emulated, these two are (one other, but forget which one) even though a little more work is needed for both systems.
>I wonder if a disc dumping status page either already exists or maybe will be created >once that more laserdiscs are worked on.
I was wondering what was available for dumping. I know there are some prototype games out there. I guess it would behoove the owners to rip them before they rot (if they haven't rotted already)
I don't understand the archiving process fully (actually not at all, lol). Is there something that can be done for "drop outs" or "misreads" if there is only one disc to sample? As in a proto.
Is there any hardware that will be hard to emulate? I know there was discussion about Star Rider doing some weird panning & zooming.
Are there any games that would be easy? Ones that may be just waiting for a rip.
>I was wondering what was available for dumping. I know there are some prototype games out >there. I guess it would behoove the owners to rip them before they rot (if they haven't >rotted already) Are there any games that would be easy? Ones that may be just waiting for a >rip.
My guess is the order will be set by which laser disc player is already emulated and then going by how many discs/copies on hand of a particular game in order to 'correct' all of the captured data to ensure a most usable image. I am guessing that means Dragons Lair might be supported first before Cube Quest or it could be a different popular widely supported game altogether. It depends if laser player is already emulated and if roms from the pcbs of the coinop laser disc game have already been dumped.
>I don't understand the archiving process fully (actually not at all, lol). Is there >something that can be done for "drop outs" or "misreads" if there is only one disc to >sample? As in a proto.
Someone had typed up an informative post here a long time ago, but I couldn't find that exact post. The post provided precise details that could easily have been a wikipedia entry by itself.
> I don't understand the archiving process fully (actually not at all, lol). Is there > something that can be done for "drop outs" or "misreads" if there is only one disc to > sample? As in a proto.
Roughly speaking, the process is:
1. Modify a laserdisc player by tapping the raw RF signal coming from the laser pickup
2. Connect the RF signal to a capture device. The custom-built "Domesday Duplicator" is the standard so far, though people have been experimenting with using devices for Software-Defined Radio (HackRF, etc.)
3. Capture the raw RF to a ginormous, massive, really big file. A 30-minute side of a laserdisc captured by the DdD takes up 90 GB. I figured out a while ago that FLAC can compress it about 2:1, and people have since written scripts to support this as a quasi-standard for the project.
4. Use the ld-decode software stack to convert the raw RF into audio and video. The fact that this works at all is nothing short of amazing. The software is still under heavy development, but already the results are often better than anything that can be done with standard A/V capture.
5. ????
6. Enjoy in MAME
One area where ld-decode far exceeds a standard laserdisc player is in dealing with poor-quality discs. The dropout compensation makes rotted discs watchable, and good discs near-perfect. There is also a tool for combining data from 3 or more captures to avoid dropouts rather than compensating for them, and to take the cleanest signal for any given line in the video. It's in early stages, but this will be huge for getting truly archival-quality transfers.
It's not clear yet exactly what path the captures will take to find their way into MAME. It could be as simple as creating files using the existing CHD format, or as complicated as doing a full software decode in real-time. I think the best answer lies somewhere in the middle, but I'm not sure where yet. If anyone is discussing this, I'd love to hear about it, and help if I can.
I can only imagine the amount of work that has been put into producing the decode software. Especially considering the somewhat bonkers nature of Laserdisk in the first place.
> 3. Capture the raw RF to a ginormous, massive, really big file. A 30-minute side of a > laserdisc captured by the DdD takes up 90 GB. I figured out a while ago that FLAC can > compress it about 2:1, and people have since written scripts to support this as a > quasi-standard for the project.
I am no expert here, but this sounds way too much GB, for a a PAL format as maximum resolution. Any lossless or uncompressed codec would produce much less than 90GB for 30minutes.
1.037 x 30frames x 60sec x 60 min = ~112 GB / hr. for 4:4:4
4:4:4 sampling = ~112 GB / hour (uncompressed)
For 10bit multiply x 1.25 = ~140 GB / hour (uncompressed)
Also FLAC is just a audio codec AFAIK, but it is true that this codec compress audio with a 2:1 ratio. One hour audio is about 300MB, so that is not the problem here.
How MAME will handle images with such a size, will be interesting. It sounds like pure madness to me, that a user should keep "master"-files with these sizes. A full Laserdisk collection would easily exceed multiple TB.
Here's how the Domesday Duplicator works, since you're thinking in terms of video, which the output of the DdD is very much not:
There is no such thing as a "frame" to the DdD. There is no such thing as a "resolution" to the DdD.
It's a blazing-fast ADC hooked up directly to the RF output of the laser pickup on one end, and to a USB3 link on the other end that streams 10-bit data in 16-bit words (because packing it would create processing overhead) at 40MSPS, which is then packed on the PC side.
2 bytes per sample at a 10/16 packing ratio. 40000000 samples per second. 60 seconds per minute. 30 minutes mentioned by WarrenO.
(2 * 40000000 * (10 / 16) * 60 * 30) works out to exactly 90 000 000 000 bytes.
Laserdiscs don't have pixels, it's analogue & they are sampling exactly what is on disc. The decoding of the video into something that can be displayed is done by ld-decode from the huge files. By keeping the large files, they can improve the decoding without having to re-read the laser discs (which may have rotted in the mean time).
There is also quite a bit of data in each frame that isn't displayed.
> 4:4:4 sampling = ~112 GB / hour (uncompressed)
CAV Laser discs, necessary for interactive use, are limited to 30 minutes.
You can't 4:4:4 sample it, it's an undecoded wave form.
> Also FLAC is just a audio codec AFAIK, but it is true that this codec compress audio > with a 2:1 ratio.
How do you think FLAC can tell whether it's compressing audio or not? It's just taking a stream of numbers with certain characteristics. What he's telling you is that the huge dumps from the laser disc have the right characteristics for FLAC to compress.
> How MAME will handle images with such a size, will be interesting. It sounds like > pure madness to me, that a user should keep "master"-files with these sizes. A full > Laserdisk collection would easily exceed multiple TB.
I still remember waiting for a while to download ROMs bigger than 1Mb, which we sometimes couldn't even store in a floppy disk because they were so damn huge!
You can see all the relevant thanks in the video's description on YouTube, but here's the output of Bega's Battle, having been captured via the Domesday Duplicator and output via the ld-decode toolchain:
> You can see all the relevant thanks in the video's description on YouTube, but here's > the output of Bega's Battle, having been captured via the Domesday Duplicator and > output via the ld-decode toolchain:
Wow. Colour me impressed. That is looking *gorgeous*.
> Its not a complete decode yet but here is a sneak peak of the first decoded data from > the EFM track on a LaserActive Laserdisc
This is really good to see, since these contain both code and video they're a bit more interesting to see emulated than your regular LD based systems, and I was worried for many years that the code would simply end up being lost.
> I am no expert here, but this sounds way too much GB, for a a PAL format as maximum > resolution. Any lossless or uncompressed codec would produce much less than 90GB for > 30minutes.
LASERDISCS. ARE. NOT. DIGITAL. They encode an analog NTSC or PAL composite signal plus separate audio (which *can* be digital on later discs but likely isn't on any of the arcade games).
The captures are large because they're sampling the analog RF signal that's encoded on the disc, and they want to make sure they're not missing any data. It's like an AppleSauce or Kryoflux capture of a floppy, where a 143K disc generates a multi-megabyte capture.
> LASERDISCS. ARE. NOT. DIGITAL. They encode an analog NTSC or PAL composite signal > plus separate audio (which *can* be digital on later discs but likely isn't on any of > the arcade games).
It's not exactly "standard" composite, the bandwidth and carrier frequencies are different, but it's the same principle. For instance around frequency 0 (e.g. unmodulated), you have the luminance signal on a ntsc signal so that you can splat it on a B&W tv with barely any filtering, while a LD puts the audio there. The LD in practice has a larger total bandwidth than composite (8Mhz instead of 6MHz iirc) and they use that to separate luminance and chrominance better, which gives a lot less dot crawl.
> > So, what's the lowdown on this? Is MAME finally going to properly support LD games? > > > Of course it will. As for when, well, you've been around long enough to know that you > never ask for timelines.
And if anyone does, Twisty will bring out the nipple clamps.
[/joking]
(But then, I'm not in a position to make such a statement...)
"Note to Noobs:
We are glad to help you but simply posting that something does not work is not going to lead to you getting help. The more information you can supply defining your problem, the less likely it will be that you will get smart-alec replies.
>> > So, what's the lowdown on this? Is MAME finally going to properly support LD games? > > >> Of course it will. As for when, well, you've been around long enough to know that you >> never ask for timelines.
>And if anyone does, Twisty will bring out the nipple clamps. >[/joking]
Twisty is gone....let's settle for Vas will smack the poster with a cricket paddle instead.
> Ian Smallshire (@IanSmallshire) Tweeted: > ld-decode and Domesday duplicator does wonders for Dragons Lair Laserdisc #Domesday86 > https://t.co/cI8dTX5Prx > > A-Noid
Look forward to this beauty once it is released on MAME one day.
I noticed that the web site domesday86.com has not had any updates since 22 Dec 19. Does anyone know if there have been any further developments on the hardware or software since, or has the project reached a stage where achieving of laser discs can commence for preservation when discs become available / found?
> I noticed that the web site domesday86.com has not had any updates since 22 Dec 19. > Does anyone know if there have been any further developments on the hardware or > software since, or has the project reached a stage where achieving of laser discs can > commence for preservation when discs become available / found?
Yes, ld-decode is still under active development, but the main devs have been unfortunately fairly busy with real life lately.
> > I noticed that the web site domesday86.com has not had any updates since 22 Dec 19. > > Does anyone know if there have been any further developments on the hardware or > > software since, or has the project reached a stage where achieving of laser discs > can > > commence for preservation when discs become available / found? > > Yes, ld-decode is still under active development, but the main devs have been > unfortunately fairly busy with real life lately.
Thanks for the update. Besides being busy with the usual life duties which I totally understand, the chaos of the virus does not help.
> > I noticed that the web site domesday86.com has not had any updates since 22 Dec 19. > > Does anyone know if there have been any further developments on the hardware or > > software since, or has the project reached a stage where achieving of laser discs > can > > commence for preservation when discs become available / found? > > Yes, ld-decode is still under active development, but the main devs have been > unfortunately fairly busy with real life lately.
Just wondering if the ld-decode development team can post any updated WIP development to the community if any progress has been made. Just like to understand the progress made to date since the last update, as to me this seems to be the last holy grail in the emu community for accurate preservation. Noted that the dev team may be busy with real life issues and hope that covid-19 does not impact on the development or their families. Be well.
> as to me this seems to be the last holy grail in > the emu community for accurate preservation.
There's also perfectly accurate audio cassette preservation still left to achieve, even though not as many people seem to be interested in it (which is a shame, since those tapes are pretty delicate).
If anyone has enough technical knowledge and can help with it, there's a dedicated #audio-cassettes channel on the Domesday86 discord server.
> >> > So, what's the lowdown on this? Is MAME finally going to properly support LD > games? > > > > > >> Of course it will. As for when, well, you've been around long enough to know that > you > >> never ask for timelines. > > > And if anyone does, Twisty will bring out the nipple clamps. > >[/joking] > > > Twisty is gone....let's settle for Vas will smack the poster with a cricket paddle > instead.
M.A.C.H. 3 - got em Cobra Command - got em Cliffhanger - got em Dragon's Lair - need em Space Ace - need em
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