Newtek TriCaster Advanced Edition User Guide Manual de usuario descargar pdf (Pagina 315)

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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 3.5, Section 3.13 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.)

 Certain projectors provide a ‘low latency mode’ to disable features of the unit that carry a heavy toll

in latency. Enabling this mode can make positioning the projector slightly more challenging (as you

may sacrifice some ability to position and scale the image using projector menu functions) – but the

latency reduction can be very worthwhile.

 Some cameras include features that add more latency than you would expect. For instance, image

stabilization (by definition) adds one field of latency and sometimes more. Disable anything of that

sort that you can.

 Latency may be slightly lower for progressive sessions, so for lowest latency, (genlocked) 720p

cameras and session are theoretically ideal (again, for genlocked sources, consider disabling

TriCaster’s Frame Sync – see Section 8.2.3).

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Newtek TriCaster Advanced Edition User Guide Manual de usuario Pagina 315