NewTek Tricaster TCXD850, User Manual, Page: 305 / 336

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Still waiting for the promised mention of ‘relativity’? OK, here it is then: E=MC
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B.3.2 LATENCY AND YOUR AUDIENCE
“Latency” - what’s that you ask? In this context, latency refers to the time it takes for the video
signal to transit one part of the IMAG path, from camera lens to final display. Latency is usually
expressed either in milliseconds or in video “frames” (typically either 25 or 29.97 to the second.)
As we said above, really a little video latency is not a bad thing as viewed from a surprisingly
short distance back into the audience. This is just as well, since for all practical purposes a little
latency is also unavoidable.
Even so, as long as audio and video are in sync at your seat , only a rather ‘significant’ degree of
latency will be objectionable – unless you happen to be very near the stage. For those in the
front rows, a few extra frames of latency
may be rather disconcerting. (It’s true that IMAG was
conceived primarily for the benefit of those further back, but if the latency is too obvious for
those nearest the front it can be disconcerting distraction.)
For this reason, it’s desirable to keep video latency to an agreeable minimum – but put away any
notion of ‘zero latency.’ Not only would this require bending the laws of physics, it would be a
bad idea.
Even before considering minimizing latency in the device chain, acknowledging that there is
always going to be some latency calls for some creative thinking with regard to practical staging.
For example, if you design your IMAG layout in such a fashion that those in the front row are
unlikely to be able to see the screen(s) without lifting their eyes from the onstage talent, they are
extremely unlikely to notice a small amount of latency.
B.3.3 LATENCY AND YOUR TRICASTER
TriCaster is a wonderful tool in the IMAG arsenal, but inevitably it is only one (albeit critical) link
in a chain of devices. It is common for each device to contribute a little to the combined total
latency for the system.
TriCaster’s portion of the total latency sum is well within acceptable standards for devices of this
sort – roughly between 1.5 and 2.5 frames (the actual amount can vary slightly within this range,
depending on several factors).