Genlock & Failsafe (4800 and 440)

The Genlock feature allows the NewTek 3Play system to ‘lock’ its video output to a reference video signal (house sync, such as ‘black burst’) supplied to its genlock input connector.

This allows 3Play output to be synchronized to other external equipment that is locked to the same reference. Genlocking is not an absolute requirement in most cases, but is recommended whenever you have the capability.

Tip: “Genlock” refers to “generator locking”. Professional video devices often provide a “genlock input”, which allows an external reference signal (often referred to as ‘house sync’) to control its video timing.

The output of video devices connected in this manner is synchronized to the reference signal, and they are referred to as ‘genlocked’.

The 3Play system accepts input from multiple video sources. Miniscule local timing differences between these may result in tiny delays during downstream switching operations.

Serving the same reference signal to i) the system’s Genlock input and ii) other video devices in the chain is the best approach, and ensures a match between 3Play system output and any downstream video devices required to handle both it and any other (genlocked) sources.


Locking all devices to house sync is important, but this alone does not actually ensure a perfect downstream match.

Consider an army marching along: each step the soldiers take occurs at precisely the same moment, so we could say their timing is synchronized.

Even so, problems result if one soldier leads with the left foot while others are on the right. Or perhaps everyone is evenly spaced and perfectly aligned but for one misfit who ‘tailgates’ the soldier ahead of him and keeps stepping on his heels.

This is essentially why the Genlock tab provides several settings. The Horizontal and Vertical Position settings pin the image in the proper space in the frame, and in doing so could be likened to making sure each marching soldier is in position relative to his fellows (as viewed from above).

The Phase setting ensures proper color alignment, corresponding to making sure everyone is on the left or right foot at the same time.

Thus, the Vert Position, Horiz Position and Phase settings allow you to tweak synchronization to arrive at an optimum match between devices. (Typically, these settings are fine-tuned with the aid of downstream vectorscope and waveform monitors.) A discussion of these adjustments goes beyond the scope of this manual, but a quick online search for the keywords “genlock” and “adjust” turns up a number of excellent references.


The ‘bi-level’ reference signal long used for standard definition television is often used for genlocking both SD and HD installations. However, if you are supplying an HD reference signal to the Genlock input (and your other equipment), select the HD (Tri-level) switch in the Reference Type area of the Genlock tab.

Note: Reference Type options do not appear for SD sessions.


This setting is applied when a Genlock reference signal is not in use. To adjust the setting, supply color bars to an input, pass that through to a video output, and then to a downstream vectorscope. The vectorscope display is completely stable when Center Frequency is properly adjusted.

FAILSAFE (4800 AND 440)

3Play’s multi-tiered ‘Always on Air’ hardware and software failsafe systems (see Section 2.6.2) provide confidence that short of a complete power failure the show will go on.

In some settings, however, more elaborate hardware failsafe systems may be in use. Typically, such systems take over broadcast duties whenever the output signal fails. In this case or for other reasons, 3Play’s failsafe video passthrough mechanism (which ensures that video output continues even in catastrophic circumstances) may be redundant, or even prevent the external system from engaging.

For this reason and others, the Failsafe section in Output Configuration has a switch that lets you to disable the A/V passthrough when necessary. By default, A/V Passthrough is off.

Tip: Only use fail-safe when a stable video source is connected to video Input 8.

Section 7.1.3

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