Epiphan Pearl Mini Live Video Production System with 512GB SSD (NA/JP) - Manual (Page 277)

Pearl Mini User Guide Adjust latency and view the SRT stream status
and there is packet loss over the network, retransmission of lost packets will not be possible and the stream
quality will suffer.
Latency can be configured at the source and at the destination. SRT uses the highest of the two
latency values.
The formula to calculate latency is:
SRT Latency = RTT Multiplier
×
RTT
where the recommended range of the RTT Multiplier is a value from 3 to 20.
The following table provides guidelines for what values to use when calculating latency. An RTT multiplier value
less than 3 is too small for SRT to be effective and a value above 20 indicates a network with 100% packet loss.
Ensure the measured buffer is less than or equal to the latency value you use.
Table 53 Suggested SRT latency values
Packet loss
%
RTT mul-
tiplier
Recovery band-
width overhead
Minimum SRT
latency
(for RTT ≤ 20
ms)
% is ≤ 1 3 33 60
% is ≤ 3 4 25 80
% is ≤ 7 5 20 100
% is ≤ 10 6 17 120
These values are from the SRT Deployment Guide. For up-to-date calculations, visit www.srtalliance.org .
For example, if the % of packet loss is 0.53 and the measured RTT is 16.506 ms, the latency calculation is:
49.518 = 3
×
16.506 ms or 50 ms of latency (rounded up).
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