Unofficially Official LD-Decode thread

It had to be made eventually ;)

https://github.com/happycube/ld-decode

Perhaps I should set up a FAQ?

1. How does it work?

2. Which would look better, a standard X0 analog to digital transfer or ld-decode using a lower end laserdisc player?

3. Which would look better, a standard X0 analog to digital transfer or ld-decode using an X0?

4. I noticed that there is a vhs-decode option in the works. How complete is it?

I'd be interested in converting my X9 as an experiment.

@ Poita:  I glanced through the X9 service manual and it seems to have the same test point as the 5xx-6xx laserdisc players located on the main board.  It should be labeled CN106.  It has 11 pins.  Pin 3 should be RF out and pin 8 is GND. Here’s a few pictures of my modded s315.  It should be just about the same procedure for you to tap your x9.  BTW, the test point probably terminates at 50 ohms so you can use a normal BNC connector and 50 ohm coax for all of the connections.

The housing I used is a 10 pin AMP MOD II housing with 2.54mm pitch and AWG 26-22 pin connectors…

The answers I got from Happycube:

1. I hacked up a video capture card to work as a direct ADC, then capture the raw RF signal from a test point on the Laserdisc player. This bypasses the signal processing/video output electronics, while the player itself works normally.

The raw signal is then demodulated into (analog) audio and video, then framing and comb filtering/color decoding are done in software. http://imgur.com/a/7VNff shows each stage of the process.

2-3. I think the X0 would win in either case, at least until the analog->digital conversion is upgraded. This is the best direct comparison I could come up with between the X0 and ld-decode (using a CLD-V2800, a rather low end player!): http://screenshotcomparison.com/comparison/128845

If my tinkering with an RF amp circuit is successful, the gap might close a little bit. Eventually I may cook up a circuit using the LPCLink2 (with the same LPC4370 chip found in the AirSpy), which I suspect will give better results.

4. Not much at all, I need good quality VHS RF samples (and/or the time to hack up a VHS deck, I've got a couple of Panasonics to butcher sooner or later). Also note that dealing with Macrovision will not be a priority.

What card is being used to capture the RF signal?

I never know if I actually understand what all of you are talking about... but just in case I do :P

Is there any chance that this project could be helpful? http://gendev.spritesmind.net/forum/viewtopic.php?f=17&t=1647

It appears that using the Pioneer LaserActive system with the PC1 PAC gives you direct access to the iso sectors on the disc. Something like http://www.kryoflux.com/?page=download might be able to capture this directly.

Maybe that signal could then be fed to LD-Decode? Not sure if that would give any better results than a graphics card solution.

I bought an OMX-4000 VGA amp off ebay to start toying around with ld decode. The auction was for one unit but the seller sent me two. I don’t need both, so, if anyone is interested, I’ll part with it for shipping costs. Send me a PM if interested.

Where is this up to?

Seems like happycube has joined with domesday project and they are now actively updating the software. I think. I can’t find any links to the updated software but here’s the facebook group.

https://www.facebook.com/groups/2070493199906024/

Seems like they have updated the ld-decode repo recently as well so perhaps that is still where to find the latest version.