How Can I Sync Video on Two or More DVMs? Like for a Video Wall or 3D application?

First, you will need a DVM7400/P or DVM7400/D. Both of these models have the sync option.

In order to accomplish perfect frame synchronization between DVM's, two requirements must be fulfilled:

- All DVMs must be locked to the same video sync source.

- All DVMs must be told to play at exactly the right moment, and at exactly the same time.

The following sections describe how to accomplish this with a DVM7400.


Video Sync

1. First, verify that each DVM is configured to receive C-Sync and that each one also has the 75ohm termination enabled.

2. Pick a DVM to be a Master clock source.

3. Using a standard BNC cable, connect the sync Output of the Master DVM to the sync Input of the 2nd DVM in the chain. If both machines are powered on, you should see the yellow LED on the back of the 2nd DVM illuminate when you connect the cable.

4. If you have more than two machines, continue by connecting the Output of the 2nd DVM to the Input 3rd DVM.

5. Continue this process until you reach the last DVM in the chain.

6. Check your work by verifying that the yellow LED is illuminated on every machine except the Master.

Triggering Synchronized DVM's Simultaneously

Accomplishing this requires a control system with enough RS-232 control ports to interface to each DVM as well as the ability to accept an external video sync source. It just so happens that Alcorn McBride specializes in designing and manufacturing these types of controllers. All of our Show Controllers have different features that allows them to support different applications. To determine which controller is best foryour application, be sure to check out our website at and/or contact an Alcorn McBride representative.

When you are ready to install the controller, you should connect its C-Sync input to the same sync source you are using for your DVM's. If your DVM's are daisy-chained, the best place to make this connection would be the sync Output of the last DVM in the chain. Once you have done that, you just need to connect the RS-232 cables to the serial ports on the controller.

The only remaining work is to write a script, or program, using a Windows application called WinScript. This script is what is eventually transferred to the controller to tell it what to do and when. There is an example script called SYNC2UNITS.AMW included with WinScript that implements synchronized playback between 2 video DVM7400 players. This is a great place pickup the basics without the need to create a script from scratch.

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