Use laserdisc player as cd-rom

Xavier

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Id like to dump my laseractive games and other rare laserdisc material.
In theory I believe I can hook up some common players to a computer and get data off of them. My guess would be that I might not be able to get full acess to the disc and may be able to only get at some data tracks here and there. The bigger problem though is that as far as I can tell these players will only communicate through say a parrallel port at a bit rate of 68kbps or in that ballpark.
If the game is huge and they could have a total of say up to 3gigs of info on them.
This would=days to dump a game if no hicups happen during that time.

Well it cant be too simple or else the Daphne team would have allready thought of somthing. Afaik they just capture video for cartoon games. If I could figure somthing out it could open up a whole new world for emulation.
 
not sonic

not sonic

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isnt the data still in an analogue format like tapes and stuff?
 
Xavier

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Some people believe so.(the video at least)
But I disagree.
I would think thered be at least some data tracks.
It was written to just like a cd-rom imo.
 
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taitai

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the control data(chapters/menu) is data. However, the video is much like a CD Audio disc in that the audio/video itself is an analog signal
 
Murray

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I'm no expert but this is what I know:

1.) It's going to depend on the disc / game. I'm pretty sure a lot of "interactive" LDs just had the LD in the player as an FMV source and it was controlled by an external computer / board. There wasn't really any data on the disc in those cases. In the case of LD-ROM discs, the data was stored in the place of the digital audio tracks.

2.) There simply won't be any "dumping" of the video signal. It's analog, plain and simple. If you want to save the video signal, you're going to have to get either a.) a video capture card that does composite video really well or one that does s-video and get an LD player that has a really good comb filter / noise reduction. I'm betting the capture card will be cheaper and easier to obtain.

3.) If your LD player has an SPDIF output (toslink or coax), you can get a direct digital stream rip of the digital channels only by connecting that to a digital input on your sound card and recording that way. The analog channels will have to be recorded over an analog connection because, well, they're analog. Any sound recording you do will have to be in real time. It's possible that you could rip the data track this way but I have no idea how you'd mount it as a disc afterward. Did they use ISO9660 on those or what?
 
SpamYouToDeath

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taitai said:
However, the video is much like a CD Audio disc in that the audio/video itself is an analog signal
Click to expand...
But CD audio is digital.
 
Xavier

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Bump, maybe somebody elses reading this
 
SpamYouToDeath

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I'm not familiar with the system at all, but may be able to help with some basic info...

How are Laseractive games stored? LD only? LD + ROM cart?
What kind of outputs does the system have? Any digital data?
Has anyone successfully run homebrew on the console?

Because it can run Sega CD games, perhaps a custom ROM could be used with a genesis module or whatever to tell the player to dump the digital data. The analog data could be played back as with normal LD...
 
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Xavier

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SpamYouToDeath said:
I'm not familiar with the system at all, but may be able to help with some basic info...

How are Laseractive games stored? LD only? LD + ROM cart?
What kind of outputs does the system have? Any digital data?
Has anyone successfully run homebrew on the console?

Because it can run Sega CD games, perhaps a custom ROM could be used with a genesis module or whatever to tell the player to dump the digital data. The analog data could be played back as with normal LD...
Click to expand...

The games are stored totally on the laserdisc. Basically one half is adio/video the other is for data. The player has a spif outpt and cd/cart controller inpts. I used a program that can dump carts from it (or any 16bit Sega) from the controller port. Thats how I got the bios. Alot of older player have serial posts on them that it may be possible to get info from but there very slow, about 56k or so. I wrote the author of the Seag transfer to ask him if theres any way to get it to read the laserdisc. Eww the app runs on cd rom :(
 
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There's the Daphne emulator which runs the 1980s Laserdisc games perfectly (by using video rips from the laserdisc games + the ROMs).

It can be done (heck the video rips of Data East's Cobra Command is about 704 MB).
 
Kyuusaku

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Laserdisc video (and originally audio) are analog waveforms, but they ARE digitally modulated like a CD (pits and lands.)
 
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Kyuusaku said:
Laserdisc video (and originally audio) are analog waveforms, but they ARE digitally modulated like a CD (pits and lands.)
Click to expand...

The problem isn't with ripping the raw data, it what you can do with that data afterwards. If it's analog you're going to have a hard (if not impossible) time playing back what you ripped. You'd have to emulate how the LD players convert analog signal to display.
 
Kyuusaku

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It's actually very simple if you know something about how TV's work.

To accurately archive a Laserdisc, the pits and lands have to be sampled at an insane rate to prevent aliasing-this is actually the really difficult part! Sadly no two Laserdiscs archived can ever be the same since there is no error correction...

Once you have the bitstream, you can digitally reconstruct the wave by demodulating it into a composite signal, filtering chrominance from luminance, locking chrominance to the colorburst to demodulate that into YIQ or YUV, convert that + luminance into RGB. To get the active video in each line you can wait for a specified time and resample the line at 720+ intervals, or just sample the entire line hblank and all and clip what isn't part of the picture at the end.

To build the picture you just need to decode composite sync using logic into hsync and vsync. When hsync is asserted, it's time to start the next line, when vsync is asserted, it's time to start the next field... if every field always has an even or odd amount of lines, it's progressive video, if they alternate it's interlaced. To interlace just merge odd fields into even ones.. simple stuff, except for the digital processing and of course the initial laserdisc sampling.
 
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Kyuusaku said:
It's actually very simple if you know something about how TV's work.

To accurately archive a Laserdisc, the pits and lands have to be sampled at an insane rate to prevent aliasing-this is actually the really difficult part! Sadly no two Laserdiscs archived can ever be the same since there is no error correction...

Once you have the bitstream, you can digitally reconstruct the wave by demodulating it into a composite signal, filtering chrominance from luminance, locking chrominance to the colorburst to demodulate that into YIQ or YUV, convert that + luminance into RGB. To get the active video in each line you can wait for a specified time and resample the line at 720+ intervals, or just sample the entire line hblank and all and clip what isn't part of the picture at the end.

To build the picture you just need to decode composite sync using logic into hsync and vsync. When hsync is asserted, it's time to start the next line, when vsync is asserted, it's time to start the next field... if every field always has an even or odd amount of lines, it's progressive video, if they alternate it's interlaced. To interlace just merge odd fields into even ones.. simple stuff, except for the digital processing and of course the initial laserdisc sampling.
Click to expand...

I think you proved my point rather than disproving it. Tedious work from the sound of it.
 
Kyuusaku

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It's no more tedious than what any capture card or TV from the last 15+ years has to do.. the difference is that they only sample the active video signal, and not a bunch of pits and lands that make up the signal. Yeah it's not practical to do it this way, it's just theoretically better since more happens in the digital domain.
 
Xavier

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Kyuusaku said:
It's no more tedious than what any capture card or TV from the last 15+ years has to do.. the difference is that they only sample the active video signal, and not a bunch of pits and lands that make up the signal. Yeah it's not practical to do it this way, it's just theoretically better since more happens in the digital domain.
Click to expand...

I remember seeing a little addon ap a few years ago that could show you the contents of a regular music cd in wav format, it would show the different sample sizes and you could choose one of the samples and simply drag ad drop. I wouldve guessed that laserdiscs where written in some kind of a book format somehow thered be a way to find the mpeg1's.
 
Murray

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Neogeofan12 said:
There's the Daphne emulator which runs the 1980s Laserdisc games perfectly (by using video rips from the laserdisc games + the ROMs).

It can be done (heck the video rips of Data East's Cobra Command is about 704 MB).
Click to expand...
I'm pretty sure Daphne works on mpeg encodings. An mpeg of the video (which was likely made using an analog capture process) is much different from the original ld signal.
Xavier said:
I remember seeing a little addon ap a few years ago that could show you the contents of a regular music cd in wav format, it would show the different sample sizes and you could choose one of the samples and simply drag ad drop. I wouldve guessed that laserdiscs where written in some kind of a book format somehow thered be a way to find the mpeg1's.
Click to expand...
That was all being done in the CDDA filesystem driver. There's no support in the red book spec for doing that. There is no mpeg1 of any sort on a laserdisc.
 
Xavier

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Well Mask of Destiny *the person who wrote the code for the program I used to dump the bios says he believes he can make it where I can get the data files of the disc, but not the video like what everybody here is saying.
 
SpamYouToDeath

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Right. The video is pure analog, there's nothing digital to read in the first place.

I would think that you could read the LD just like you'd read a Sega CD drive; according to wikipedia at least, they released Sega CD games on LD for the laseractive along with a genesis plugin.
 
Xavier

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my laseractive thread right below this one
SpamYouToDeath said:
Right. The video is pure analog, there's nothing digital to read in the first place.

I would think that you could read the LD just like you'd read a Sega CD drive; according to wikipedia at least, they released Sega CD games on LD for the laseractive along with a genesis plugin.
Click to expand...
 
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