Domesday Duplicator User Guide

Overview

The Domesday Duplicator GUI is a fully-graphical environment for performing RF capture of laserdiscs from an Ubuntu desktop computer.  The application allows simple user-controlled capture as well as more advanced ‘Player Integrated Capture’ using the Pioneer LD-V4300D laserdisc player.

In order to use the integrated laserdisc player the Ubuntu machine should be connected to the laserdisc player using a serial cable (or USB to serial adapter cable) and the necessary serial adapter for the player’s serial output connector.

Installation

USB device permissions

In order for the GUI application to connect to the Domesday Duplicator USB device it is necessary to provide permissions for user-level access.  For this you need to create a file called 40-domesdayduplicator.rules in the /etc/udev/rules.d directory (requires root permissions).  The contents of the file should be as follows:

# Domesday Duplicator
SUBSYSTEM=="usb", ATTRS{idVendor}=="1d50", ATTRS{idProduct}=="603b", GROUP="plugdev", MODE="0666", SYMLINK+="domesdayduplicator"

Serial port device permissions

If you want to use the player integrated capture feature a serial connection between the Ubuntu host machine and the laser video disc player is required.  In order to access a serial device the user must have ‘dialout’ group permissions.  This can be added to the current user account using the following command:

sudo usermod -a -G dialout $USER

Note that this permission does not become active until the user account has logged out and logged back in again.

User-controlled capture

When the capture application is used without player integration enabled the main window only enables the basic capture functionality as shown below:

Domesday Duplicator GUI with player integrated capture off

The status bar (at the bottom of the window) shows the state of the Domesday Duplicator USB device as well as the state of the player integrated capture feature.  Capture is not possible until a valid device is connected to the computer (and the status bar shows ‘connected’).

In order to enable the ‘Start capturing’ button you must select ‘File’ from the menu bar and select a destination file for the capture.  All captures are written to the same file until you change the destination file name again (i.e. each subsequent capture will overwrite the previous capture).

When a capture is in progress the application will show the total captured data and the current data transfer speed in the ‘capture statistics’ section of the window.  The disk buffer status will show the percentage of free disk buffers during the capture.

NTSC and PAL capture rates

The Domesday Duplicator GUI allows you to select between NTSC and PAL capture rates.  This selection is to allow sampling at 8 times the colour-burst frequency of the standard (this is mathematically significant when decoding the resulting RF samples back to video).  Due to limitations in the accuracy of the clock generation provided by the DE0-Nano the following sampling rates are used:

  • 28.63632 MHz NTSC sampling clock: actual 28.636364 MHz
  • 35.46895 MHz PAL sampling clock: actual 35.470085 MHz

Note that the duplicator will capture both NTSC and PAL at either sample rate (and it is possible to decode video from both standards at either sampling rate), however 35.5 MSPS is recommended for PAL and 28.8 MSPS for NTSC to achieve the best results.

DC offset compensation

Due to a small hardware issue in the Domesday Duplicator revision 2_0 PCBs there is a slight DC offset in the sampled RF produced.  Ticking this option compensates for the DC offset when capturing.  If you are using a revision 2_0 board you should ensure this option is selected before performing any captures.

Test data generation

In normal operation the ‘generate test data’ check-box should remain unchecked.  If you check the ‘generate test data’ check-box the application will tell the Domesday Duplicator hardware to use test-mode during any capture.  This option should not be used unless you are developing software for the duplication system and will result in invalid samples if used incorrectly.

In test-mode the Domesday Duplicator hardware will ignore the player’s RF information and send a repeating sequence of numbers to the application.  The application uses the known sequence to test that both USB transfer and disk transfer are being performed successfully.  This option is primarily for development purposes but can be useful when testing your capture set-up to ensure that both the USB and the disk hardware in your PC provide the required speed for real-time RF capture.  If any test-mode transfers are unsuccessful the ‘test mode fails’ counter will increment to show the number of detected errors.

Viewing version information

To view information about the application, copyright notices and other information select the ‘About’ option from the ‘Help’ menu in the main menu bar.  This will display a window similar to the following:

About dialogue window

Player integrated capture

Player integrated capture requires a serial connection from the PC to the Pioneer LD-V4300D player.  It is recommended that you install and test the serial connectivity (using an application such as PuTTY or CuteCom) before using the PIC feature of the application.

Configuring the serial interface

In order to enable PIC features you will first need to configure the serial interface of the PC towards the laserdisc player.  To configure the serial interface select the ‘Select player COM port’ option from the PIC menu (in the main menu bar of the application).  This will display the following window:

Serial configuration dialogue window

Clicking on the ‘COM port’ drop-down will display a list of the available serial interfaces on your computer.  Select the correct serial device for your laserdisc player.  The LD-V4300D supports three different communication speeds (it is recommended to use 9600 BPS for the best performance).  Please see the laserdisc player manuals for information on how to configure the serial communication speed of the player.  Select the correct communication speed by clicking on any of the available radio-button options.

Once you have selected the correct options, click on the OK button to configure the serial port.  To quit the window without selecting a serial configuration, click on the Cancel button.

Note that the ‘COM port’ selections include an option for ‘None’.  If you configure this option the application will be disconnected from the laserdisc player.

PIC options when a disc is not playing

When no disc is playing in the laserdisc player the main window will show the following options:

Main GUI – PIC with no disc playing

When no disc is playing, the application cannot determine if the disc is present (i.e. inserted in the laserdisc player) or if the disc format is CAV or CLV, so integrated capture options are provided for both formats.  Clicking on the ‘Capture’ button will cause the application to attempt to start playing the disc and perform the required automatic capture.  If you instruct the application to perform a CAV integrated capture with a CLV disc in the laserdisc player, the capture will abort as soon as the disc type is detected (and vice-versa for the CLV capture with a CAV disc).  The details of the CAV and CLV integrated capture functions are provided in the sections below,

PIC options when playing a CAV disc

When a CAV disc is present in the laserdisc player and the laserdisc player is either playing or paused, the main window will be as follows:

Main window with CAV disc playing

In this mode you can either perform a manual capture (using the ‘start capturing’ button) or perform an automatic capture.  To perform an automatic capture, simply enter the start frame number and the end frame number for the capture and then click on the ‘Capture’ button.  The application will automatically confirm that the required frames are available, move the player to the correct position on the disc and start the RF capture process.  Once the disc reaches the required end frame number, the application will automatically stop the capture and pause the disc.

Note that the communication with the player is only ‘near real-time’ due to the nature of the serial interface.  The status of the player and the application’s view of the player may be slightly delayed.  This can cause automatic capture to overrun by several frames before and after the desired capture start and stop.

During automatic capture the ‘status’ text is updated to show the current operation being performed by the application.

To abort an on-going capture simply click on the ‘Capture’ button again (note: this button is changed to ‘Abort’ during capture).  This will stop the transfer and save the collected RF data to the specified file.

In addition to the automatic capture, the application also provides interactive control of the laserdisc player from the application.  To view the interactive control select ‘Show player control’ from the PIC option in the main menu.  This will display the following window:

Player control window (CAV)

This window shows a live view of the laserdisc player’s status (playing, paused or stopped) as well as the current frame position.  The ‘player controls’ allow you to manage the player from the application.  Clicking play will send a play disc command to the player (if you click play during playback, the application will send a pause command to the player).  The ‘Step >’ and ‘Step <‘ cause the player to step one frame forwards or backwards and then pause on the selected frame (you can continue playback by clicking the ‘Play’ button).

The ‘Scan >’ and ‘Scan <‘ buttons cause the player to skip approximately 500 frames forwards or backwards for every click.  The player resumes it’s previous state after the scan is complete.

Pressing the ‘Stop’ button while the player is playing will cause the player to stop playback.  Pressing the ‘Stop’ button when the player is stopped will cause the disc tray to eject.

The ‘CAV controls’ section allows you to jump quickly to any frame on the disc.  Simply enter the frame number into the frame box and click the ‘Seek’ button.  The player will move to the specified frame number and pause.

The ‘Lock physical controls’ check-box allows you to lock the physical buttons on the laserdisc player.  Locking the laserdisc player controls is not required for correct operation; if you operate the player manually, the GUI will automatically update accordingly.

PIC options when playing a CLV disc

Since CLV discs do not support frame numbers, the PIC options for CLV discs are slightly different (although the overall operation is the same).  Also note that CLV discs do not allow a ‘still frame’ when paused (the display is blanked when paused).

The player control window will be as follows for a CLV disc:

Player control window (CLV)

Controls are the same as for CAV discs, however the ‘Step’ buttons are not supported for CLV discs, so are disabled.  The CLV controls box allows you to specify a time-code (in the format HH:MM:SS).  Entering a valid time-code will cause the player to seek to the correct position on the disc and pause.  Note that the player information also displays the current position as a time-code.

Capture from lead-in option

Laserdiscs contain ‘lead-in’ information which is read by the player before playback begins.  An automatic capture of the disc beginning at frame 0 will not capture the RF from the lead-in process (as the player is moved to frame 0 and paused before capture begins).  In order to capture the lead-in the RF capture must begin before the disc is ‘spun-up’ into playback mode.  Checking the ‘Capture from lead-in’ option causes the application’s automatic capture logic to change the way a disc is captured.  When the option is selected it is not possible to specify the start frame or time-code (as this will always be the beginning of the disc).  With the option checked the application will stop the player before beginning RF capture.  Once RF capture is running the application starts the player and continues into playback mode ensuring that the lead-in data is captured.

Additional notes

Old CLV disc may not contain a time-code

During testing some (very old) CLV discs were tested that did not contain time-code information (only chapters).  These discs will not work in PIC mode and must be captured manually.

End-of-disc seeking

As part of the PIC capture process the application attempts to seek past the end of the laserdisc in order to determine the length of the laserdisc (in frames or time-code).  Old discs (especially those suffering from damage around the edge or laser-rot) can have problems playing the area around the outside of the disc (i.e. the end of the disc) and the PIC seek operation may time out causing an aborted capture.  In these cases use manual capture.

Early USB 3.0 motherboard hardware

Some early motherboards do not correctly support USB 3.0 bandwidth requirements and may fail to work with the Domesday Duplicator hardware; there is no way for the duplicator hardware to compensate for such hardware.  If in doubt, please test the duplication process on another PC or ensure that your hardware supports the USB 3.1 standard (as this indicates that the USB hardware is modern).