Reference Clock and I/O Configuration

Reference Clock

If you will be using the SDI AoIP Node simply to de-embed, pair shuffle, route, and re-embed only SDI signals and will not be connecting it to an AoIP network, navigate to the I/O Menu and choose "SDI1" or "SDI2" as your reference in the Reference clock dropdown (1A). If desired, you may choose a secondary reference clock as a backup should the unit lose its reference from the primary clock source.

If you are connecting to an AoIP network with a Master PTP Clock, you must choose "AES67/PTP" as your clock reference.

Inputs and Outputs

SDI AoIP Node can access any of the eight audio pairs carried on each of the two available incoming HD- or SD-SDI streams, pair shuffle to the two HD- or SD-SDI outputs, or route audio to an AoIP stream.

Incoming AES67 audio sources can be embedded to an SDI output, and embedded SDI outputs can in turn be sent out as AES67 streams.

SDI I/O

The SDI 1 and SDI 2 connections each have their own routing controls under the I/O Menu. The controls for each are identical.

Each of the SDI input pairs is simply labeled according to its pair number ("SDI In 1/2") but can be renamed by clicking on the Label field (2A), typing in the desired name, then clicking on the green checkmark to save.

SDI output routing is set by the SDI Out dropdown (2C) for each pair. Pair shuffling within or between SDI inputs is supported, or any available AES67 source may be selected.

All Sample Rate Converters (SRCs) on both the SDI Inputs and Outputs are enabled by default but can be disabled on a per-pair basis using the Input SRC (2B) and Output SRC (2D) switches. Doing so does lower throughput latency slightly, but there is no disadvantage to leaving them enabled. In fact, if there are any anticipated reference clock changes (either intentional or unplanned) it is safer to leave them enabled.

AES67 I/O

Settings for the AES67 I/O are found under the I/O Menu.

To set an AES67 input, enter the Livewire channel number or multicast address of the AoIP source directly in the Address field (3A) or use the channel picker (3B) to see a list of available sources. Livewire channels will automatically resolve to their corresponding multicast addresses.

Use the AES67 Output dropdown (3D) to select any audio pair from either SDI input or any AES67 input pair. Assign the output a Livewire channel number or a multicast address in the Address field (3E). As with the input, Livewire channel numbers will automatically resolve to their corresponding multicast addresses.

GPI/O

SDI AoIP Node features a rear-panel DB-15 connector for momentary GPIO contact closures. This feature will be implemented in future software versions and is not currently supported in V1.2.006.

GPI/O Pinout

Delays and A/V Sync

An adjustable video delay is provided in the Delays section of the I/O menu to compensate for the audio latencies in the broadcast system and to ensure correct A/V sync at the output. Each SDI path has its own Video Delay (5A), adjustable by clicking on the millisecond (ms) or microsecond (us) field, entering the desired value, then clicking the green checkmark to save.

In instances where the SDI output needs to be delayed by an even frame (the value of which will vary depending upon frame rate) simply enter that number. It may then be necessary to compensate for the difference between that time value and the latency of the unit by clicking in the Audio Delay (5B) field, entering the desired value, then clicking on the green checkmark to save.

Latency values are as follows, measured using an SDI input to an AES67 network, through the SDI AoIP Node, and to an SDI output:

• 121ms with input and output SRCs disabled

• 127ms with input and output SRCs enabled