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GENLOCK TAB

TriCaster’s Genlock feature allows it to ‘lock’ its video output to a reference video signal supplied to its Genlock input connector. (Note that TriCaster 410, TriCaster Mini SDI and Mini do not provide Genlock support.)

This synchronizes TriCaster output to other external equipment locked to the same reference.  Genlocking is not a requirement, but it is very beneficial, and you should definitely use it if you have the capability.

TriCaster mixes and switches output from up to eight directly connected local camera sources (4RU models). Miniscule local timing differences between these may force tiny delays during switching operations, which can also contribute to throughput latency. Thus, serving i) TriCaster’s Genlock input and ii) other video devices in the chain with a single reference is the best approach.

You could think of it this way:               

  • Genlocking your cameras has the effect of locking their output together, ensuring optimal synchronization for live switching. This may result in throughput latency benefits.

 

  • Supplying the same sync source to TriCaster’s Genlock input ensures a match between TriCaster output and any downstream video devices required to handle both it and other (genlocked) sources.

 

Hint: The term “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’.

Note: Digital audio is less tolerant in certain respects than analog.  Some devices require SDI sources to be genlocked when mixing digital audio (whether for recording or live production).

TriCaster, however, includes dynamic audio re-sampling for each input. Genlocking of SDI audio/video sources is not a requirement.  Still, genlocking sources and TriCaster to a house reference signal, or genlocking the cameras directly to the TriCaster output is encouraged (to genlock cameras, see your camera manual).

Genlock settings are hosted in a tab by the same name in the Hardware Configuration panel (Figure 79).

Vertical Position, Horizontal Position and Phase

 

Figure 79

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 everyone else is 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 TriCaster provides several adjustments in its Genlock section. 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 a downstream Vectorscope and Waveform Monitor. (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).

Reference Type

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 TriCaster’s Genlock Input (and your other equipment), select the HD (Tri-level) switch in the Reference Type area of TriCaster’s Genlock settings. 

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

SECTION 8.2.3

For more information please download the entire document at new.tk/rt-m

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