Latency and Delays
Latency through the UPMAX ISC varies depending on which inputs and outputs are used and whether or
not SRCs are enabled. In any case, it will be necessary to compensate for any latency incurring in the
encoding process. Please see the Specifications section of this manual for latency measurements for the
current software version.
To compensate for the processor’s latency and avoid lip-sync issues, an SDI video delay is provided in the
Delays sub-menu of the I/O menu (5-7A). Click on the millisecond and/or microsecond fields in the Video
Delay section (5-7B) and type in the required value. If the output needs to be delayed by an even frame (the
value of which will vary depending on frame rate), simply enter that number.
Note: Entering an even frame value will result in a situation where it is necessary to add additional
audio delay to the AES67 and AES-3 outputs so that they match the timing of the SDI output
signal. This can be accomplished by setting the Audio Delay (5-7C) to a value equal to the
difference between a full-frame and the latency of the unit.
Figure 5-7 - Delays menu
Sample Rate Converters
Sample rate converters (SRCs) are provided on each SDI input pair, each SDI output pair of the first SDI
output, and each AES-3 input pair, for a total of 36 SRCs altogether. The AES-3 output is always synced to
the active reference clock. There are no SRCs in the AES67 path.
The SRCs can be enabled and disabled per pair by clicking on I/O (5-8A), highlighting then right-clicking on
the appropriate input or output pair, and then selecting Input Settings (5-8B) (or Output Settings as
appropriate).
Use the SRC enable switch (5-8C) to enable or disable the SRC for each active pair.
