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Posted: 14 Nov 2017, 10:25 

Just a quick update; the production boards are now designed and I'm in the process of ordering some to continue testing with. Here's a render of the board design:

Domesday Duplicator_Render.jpg

Software is still on-going; but I'm getting there :)

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Posted: 12 Dec 2017, 07:16 

I realize I've been quiet about the duplicator board progress, so here is a quick update:

I've completely rewritten the FPGA code for the project to make everything more robust and to increase the level of system testing and the error checking. The design now runs the FX3 (USB 3) communication at 64 MHz (double the capture speed) to allow better buffering and 'catch-up' when the PC slows down for any reason - the non-realtime nature of a PC performing the capture to disk causes bursting of data via the USB3; this is now much better implemented.

I've also written a Linux (Ubuntu) GUI front-end application in QT which monitors and controls the capture process. The latest github build is a fairly simple GUI, but contains a robust USB and disk buffering implementation that has been tested successfully with capture runs of over 60 minutes (generating in excess of 250Gbytes of capture). By making an open-source Linux application specifically for the duplicator I can now expand the functionality at will to make the capture process far more user-friendly. Also the whole 'chain' of the capture and decode process can run on a single Linux machine (before the capture relied on the Cypress FX3 Windows test applications for capture).

I have now received 3 Pioneer LD-V4300D laserdisc players and these players will be the reference hardware for testing the Domesday Duplicator board. The new players are both NTSC and PAL capable, so they represent a much more universal approach than the Sony PAL player I was using previously. To get the best results the players need to be correctly calibrated and set-up. I've ordered the required Pioneer 8" test disc (from PacParts in the USA) and some service remotes - I also have the service guides and the test equipment required.

I've also just ordered the parts to make up a couple more Domesday Duplicator boards; these should be ready by the new year and will be used to expand the testing scope (one will go to Mr Happycube and the other will be a secondary test card for my own rig).

I'm also planning on implementing what I call "Player Integrated Capture" into the Linux application - this will provide automatic control of the LD-V4300D from the Linux GUI. Full and partial disc capture will be controlled automatically between the Linux app and the player using the RS-232-C player interface. This should take out the hassle of capturing disks and allow additional things like multiple captures of a range of frames where the GUI pauses on a frame automatically, checks the player is where it should be, captures, and then moves on. Once the VBI frame position information is exposed via ld-decode, this should allow for really smart capture techniques - especially when only one source laserdisc is available. Basically you will be able to specify a frame or range of frames in the app and it will all happen automatically. My plan is to implement this in 'layers' so others can easily add in support for additional laserdisc players.

Once the new LD-V4300D machines are running and I have an end-to-end tested capture, I'll push a Github release (hopefully in the next 2 weeks). After that, everything is just 'enhancement' work :)

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Posted: 13 Dec 2017, 21:20 

Well, the good news is that the capture system is up and running again - the Linux GUI app needs more work (cosmetic fixes and non-capture related bugs); but I now have a modified Pioneer LP-V4300D with the RF tapped. I haven't calibrated the player yet (I'm waiting on a service remote control and Pioneer 8" test disc to be delivered). The whole software base is now far more robust and reliable with better design everywhere, especially around the FPGA dual-clock domain FIFO buffering; the USB communication is now 64Mhz (double the capture rate).

ld-decode seems to be happy with the captures however there are some issues with both black and white colours being very speckled and not very black (or white); but I'm sure this is just some ld-decode calibration issues.

Happycube - expect some rather large captures from the Jason disc and the Domesday Community South disc (I'm grabbing a frame dump of all of the test cards). I'll also include some NTSC from the Fantasia disc since I can now capture both formats. I don't have any NTSC testcards (yet), so some animated frames will have to do.

For everyone else; here's a pretty lady from the Jason disc captured using the new set up :)


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Posted: 14 Dec 2017, 21:15 

The Domesday Duplicator is now in release status. I'll be working on enhancing the Linux GUI front-end some more, but the whole set-up is now working end-to-end from the high-speed DAQ through to the Ubuntu GUI.

Documentation is fairly complete and includes construction information, bill of materials and much more (but requires more detail especially around the GUI). You can find the documents via the following links:

Hardware guide:
Software guide:

The Github repository is available here:

This release is primarily for testing with ld-decode (rather than prime-time use) - but if you are interested in how it works and what it is, all of the required information is now available.

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Posted: 26 Dec 2017, 10:38 

Glad you liked the guides :) I'm trying to make sure this work is as 'universally useful' as possible!

The Domesday Duplicator software is using the LD-V43000D as the reference player and provides fully automated CLV and CAV capture; so it's getting easier and easier to quickly and accurately capture RF. My aim is to make it as 'untechnical' as possible for end-users. Here's a view of the latest github of the capture software:


Nearly there! :)

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Posted: 21 Apr 2018, 20:20 

I've just pushed a pre-release of the new Domesday Duplicator software to github:

This version has many improvements and bug-fixes and includes new GUI application code, Cypress FX3 code and FPGA code (you will need to update all three). The release is compatible with the 2_0 revision PCB (you must set DC compensation to on though in the GUI) and the github has the new revision 2_2 PCB and Kicad schematics. The revision 2_2 board is awaiting test though (I'm waiting for PCBs to be delivered from China before this can begin).

The new software supports 8xFSC sampling for NTSC (at 28.8 MSPS) and PAL (at 35.5 MSPS) rather than the fixed 32MSPS sampling of the previous version. There's also a lot of improvement around error handling to make the GUI usable without needing the debug output when things go wrong with device communication.

I've also revamped the build environment (and ironed out some multi-threading issues) so the GUI can now be built in release mode from the Ubuntu command line (makes it simple to build and gives it an Ubuntu look-and-feel):


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Posted: 21 Apr 2018, 20:25 

Here's a sneak-peak of the 2_2 PCB. It's smaller (to get the length under 10cm which reduces the cost for fabrication since 10cm is usually the 'price-break' point) and has been much more carefully laid out to make it easier to construct. The silkscreen is also greatly improved to make it both better looking as well as clearer as to where the components go. It also has a fix for the DC offset issue, but that is subject to test (however the board can be configured to act just like the 2_0 version if needed). All the documentation has also been updated on

Domesday Duplicator V2_2 small.jpg

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Posted: 01 May 2018, 05:59 

I know this topic is primarily about making a copy of the (analog) video

That's not entirely the case :) The digital information on the disc is also encoded in the analogue modulated signal using a technique called EFM. If you capture the raw RF you get everything on the disc without exception.

This is the reason why I designed the Domesday Duplicator for my project to preserve the BBC Domesday system:

Although Domesday is PAL; the duplicator works with both NTSC and PAL. However... capturing the raw RF preserves the information on the disc, but it doesn't allow you to simply read it; for that you need a decoder (which is what ld-decode is about) - right now there is no capability to decode the EFM data, but it could be added. The details of how this is done is contained in the following (commercial) IEC specifications:

IEC 60856-1986 Laservision PAL
IEC 60856-1986 Laservision PAL Amendment 1
IEC 60856-1986 Laservision PAL Amendment 2
IEC 60857-1986 Laservision NTSC
IEC 60857-1986 Laservision NTSC Amendment 1
IEC 60857-1986 Laservision NTSC Amendment 2
IEC 60908-1999 CD digital audio system

The last spec about CDs is because the EFM encoding was developed for CDs, but used for LaserDiscs to provide both digital data and digital audio.

I've written a high-level description of the way information is decoded by a LaserDisc player which you may find useful:


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Posted: 14 May 2018, 12:01 

Nice work on the Windows port! Looks promising :)

Since there is a lot of discussion and interest around the Domesday Duplicator (as well as the Domesday86 project as a whole) - I've just made a facebook group for the project where people are welcome to ask questions and seek support. Anyone interested is welcome to join:

Somehow I need to control all the emails and PMs I've been getting recently :)

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Posted: 17 May 2018, 14:29 

I'm only working on NTSC decoding right now, so the PAL test cards aren't much help yet. I don't have any test card samples for an NTSC signal. I tried to capture a generated one from a test ROM for the Mega Drive via the composite video stream today, but I had trouble getting my test machine to cooperate. A straight composite signal isn't in the right range for the Domesday Duplicator analog input, and cdaxc kept on dropping samples randomly for some reason. It's worked before, so I'll have another try later. I should be able to get something usable out of it.

About a million bug fixes later though, and I have something that's vaguely in the region of viewable:
What I'm discovering is that phase locking to the colour burst is hard! I underestimated just how sensitive it would be. The slightest variation and the hue goes off in perceivable ways, but from the RF the signal isn't even regular, and captures from consoles and other equipment I have which generates composite video shows they have their own problems and idiosyncrasies, from field timing that's off NTSC spec, to colour burst waves that look more like triangle or square waves, with length and position wildly varying. Analog receivers cope with them all though, so you can't just go by what the specs say, the software needs to at least be able to cope with anything an analog set could have thrown at it, because there's a kaleidoscope of "incorrect" signals out there that work anyway. I'm trying to write software which can adapt to all this, but writing something that's adaptive and tolerant of signals that are generated off-spec, while still pulling in imperfect signals which aren't regular back into conformity so the image is stable and correct, isn't an easy task. Underlying all this there's the loss of information problem, in that as soon as we quantized the analog waveform we approximated it, and even with good interpolation techniques, it's never quite as easy to derive precise, accurate information about the true frequency of a waveform, or the exact points at which it crosses certain thresholds, as it is to build an analog circuit which naturally derives that information in a precise, adaptive, and near perfect manner from the true analog waveform.

I can see I need to take a good look at the TBC issue again, and separate it clearly from framing. I need to first of all decide what the "correct" timing appears to be for the video stream, then use that information to perform TBC to force the input signal into conformity to that, but without distorting the hue mid-line by stretching or compressing the signal inappropriately. You've got a damn near perfect process working for that already happycube, but for a limited range of input signals. I'm going to have to spend some time planning an alternate approach here I think, which can achieve the same great result you've obtained, while making it more adaptive on the range of input signals it will accept. I might start by grafting in your existing comb filtering code into the back-end of my video decoder, so I can use a mature colour decoding process, and focus on making the input to it more flexible and adaptive. Once I've got that process getting a result on par with what you're currently achieving, but with a wider range of signal support, I can focus more on the colour decoding issue itself. Even without further work though, at that point I think it'll be up to task for a lot of things I'd like to use it for.

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Posted: 25 May 2018, 05:21 

You're right, the values are quite different with 50ohm termination on my 'scope:

- ~200mV ggv 115, ~312 ggv end
- ~408 AVS end

Looks like the attenuatior above a certain voltage lets too much of the audio signals (esp CD/EFM) get through, so I'll hopefully take it to the local Hackerspace tomorrow for a resistor swap.

Other random not-enough-coffee-and-slept-on-my-shoulder-wrong-again thoughts:

- @nemesis - looks like you're making good progress! Something that worked well for me was looking at a line and the two color bursts around it - my current TBC takes 2-3 passes.

- The DE10-Nano has an ARM SOC + FPGA, with HDMI output. With a lot of work it might be possible to do real time video decoding through that.

- I think a data stream format that reflects the EFM subchannels is going to be in order sooner or later. It would be good for [C/L]D-G. It doesn't have to be completely raw EFM but it could have a packet format that covers anything non-zero.

- CDV-R's existed in Pioneer's lab at least. They had special blanks... in theory someone could hack up a burner for it, but it would be a ton of work I doubt anyone will ever do. (but feel free to prove me wrong there!)

- If flash keeps getting smaller/cheaper we're not that many years off from affordable 256GB microSD cards that could store a disk's worth of 8-bit LD RF. Or four Blu-Ray rips. Or who knows how many hours of SD video with modern encoding ;)

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Posted: 25 Sep 2018, 17:51 

This is a 7 pin connector on the DVDM board CN106 and is listed as RS232C, so it "should" comply with standard serial protocols and voltages. It's on the edge of the board between the two cables that go down to the CLDM board.

1 - NC
2 - GND
3 - +5v
4 - CTS
5 - DTR
6 - RXD
7 - TXD

One of my 919E boards has a little fob in this port that makes it region free. If I remove the fob, the player reverts to its original region coding.

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Posted: 27 Sep 2018, 13:26 

Just a thought, but if you connected that 'fob' to a serial to USB adapter (a TTL level one like the arduino's use) and connected it to a PC, then connected the +5V, it would fire up and you could read out the commands it's using to do the region free trick... then you could publish the codes required here (or make more dongles and sell them as gold bars :) ).

Either way you would then know the serial speed/settings and at least a few of the available commands.

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Posted: 26 Dec 2018, 04:02 

Most of the discussion is on the #domesday86 freenode channel now, along with the FB group, so while this thread's been silent there's still been plenty of good progress :)

New software release (rev3) today, which includes Simon's tools.

PAL quality is greatly improved: is a 1-minute Domesday intro. Really pushing what the source material: a PDO UK disk from 1986... at the beginning of a CAV disk where higher frequencies are truncated. A MUSE PAL player would really help here, but they don't exist.
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