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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).
For example, suppose a ‘video frame’ supplied by a camera arrives at TriCaster’s inputs
one millisecond after a different frame has been sent to the output. Obviously the new
arrival must wait its turn; it can’t be transmitted until the correct duration for its predecessor
has elapsed. Thus the newly arrived frame must ‘wait’ almost one entire frame, until its
turn comes.
How can you achieve the lowest possible latency for the TriCaster section of the IMAG
chain? One trick is to ‘Genlock’ your cameras to the TriCaster output (see Sections
Section 3.6, Section 3.14 and 8.1.2). This allows TriCaster to bypass its input time-
base correctors, ensuring latency is consistent during switching operations. For
genlocked sources, consider disabling TriCaster’s Frame Sync – see Section 8.2.3.
Hint: you can actually assess the latency of your TriCaster installation fairly easily. Run
timecode directly to 1) a monitor and at the same time 2) through the TriCaster to a second
(identical) monitor. Take a photograph that encompasses both monitors, and compare the
timecode shown!
B.3.4 OTHER SOURCES OF LATENCY
More often than not, significant latency is added by other devices in the IMAG chain
that come after the TriCaster. Projectors are a common contributor, but at times the
cameras themselves are a factor.
Here are some helpful points to consider when designing and connecting your
system:
If you use Multiview output from the TriCaster to the projector -- if at all
possible, match the resolution sent from the TriCaster to the native resolution
of the projector. (On some projectors this allows the unit to avoid using its
own internal scaling, which is often a significant factor in unwanted latency.)
When possible, try supplying the projector with analog video. This can
eliminate a lot of the complexity from the process (of course, this is not always
possible.)
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