I/O, Clocking, and Reference

Input and Output Routing

Connect your SDI, AES-3, and/or AES67 sources to the rear panel of the LA-5300 as required for your installation.

The LA-5300 can access any of the eight audio pairs carried in the incoming HD- or SD-SDI streams applied to SDI Input 1. Inputs and outputs for five stereo pairs via AES-3 are also provided.

Any visible and accessible AES67 networked audio source can be input into LA-5300 for processing then returned to the network via AES67, embedded into the SDI output, and/or sent to the AES-3 output. LA-5300 supports taking an input signal from one source type and sending the resulting audio or bitstream to another output type.

Initial I/O Setup

Log into the LA-5300 and click on the I/O menu (1A). Choose between SDI/AES-3/MADI or AES67 inputs and outputs in the Workflow menu (1B). Select between viewing Program (processed) and Passthrough (unprocessed) routing with the Program/Passthrough switch (1C).

Figure 1 - I/O menu

Routing a signal into the LA-5300 is a two-step process.

First, create an input group from the available physical hardware inputs (2A). Next, route the audio from these inputs into the processor input (2B).

Routing a signal to the output is a similar two-step process.

First, create an output group from the available physical hardware outputs (2D). Next, route the audio from processor output (2C) to the physical outputs.

Figure 2 - Signal routing menu

Creating an Input Group

Click on your first audio input source (3A) to highlight it, then right-click and select “Create Input Group.” You may enter a custom name for this source in the Label field (3C) and customize the color (3B) of the graphical routing lines.

Multi-channel groups can be created by holding the “Shift” key while selecting sources (Shift + Click).

Creating groups using non-contiguous channels is accomplished by holding the “Ctl” key while selecting sources (Ctl + Shift).

Note - The channel order must still follow the proper convention to be properly assigned. For example, L/R, C/LFE, Ls/Rs, Lfh/Rfh, Lrs/Rrs if setting up a 5.1-channel input on SDI 1-6 with height channels on SDI 13-16.

Click the Save button (3D) to save the configuration or the Cancel button (3E) if you need to start over without saving your configuration.

Figure 3- Creating an input group

Routing Audio to the Program Input

After saving the input group, it is necessary to first set the priority of the input source by dragging the input audio lines (4A) and then clicking when the desired priority level (4B) is highlighted. The LA-5300 will look for audio first on inputs connected to Priority 1. If no signal is present, it will look to subsequent priorities in order.

Figure 4 - Routing input audio and setting the priority

Next, choose the input signal type (PCM, DD+, EAS PCM or AC-4) from the Type dropdown menu (5A).

Note - Whenever EAS PCM is used, it should be set as Priority 1 to ensure EAS alerts always have priority over any other program.

Figure 5 - Selecting the input signal type

To edit or delete a group, highlight then right-click the colored Edit rectangle (6A).

Figure 6 - Editing or deleting an input group

Creating an Output Group

The steps for creating an output group are identical to creating an input group, but with the Outputs menu.

Routing Audio to the Program Output

Once the first output group has been created and saved, drag the output audio lines from the group to the desired program output, then click to save.

Latency and Delays

Latency through the LA-5300 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 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 (7A). Click on the millisecond and/or microsecond fields in the Video Delay section (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 (7C) to a value equal to the difference between a full frame and the latency of the unit.

Figure 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. 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 first highlighting then clicking on the appropriate input or output pair, and then selecting Channel Settings (8A).

Important! Only PCM audio can be passed through a Sample Rate Converter. Coded audio bitstreams including Dolby Digital Plus and Dolby AC-4 cannot be passed through an SRC without corrupting the data stream.

Figure 8 - Sample rate converters

Clock Reference

Because the LA-5300 offers very flexible signal routing and supports multiple input and output formats, having a firm grasp of the clock sync (reference) requirements is critical.

Clock Reference Requirements

Reference clock source options include:

• Internal 48kHz

• SDI Input

• AES-3 Input

• MADI Input (when optional MADI card is present)

• PTP (AES67)

When all input sources are SDI and the output of the processor is routed to the embedded SDI output, the reference signal present on the SDI input must be used.

When using AES-3 I/O, the LA-5300 can be referenced to either the AES-3 clock (using the SRCs in the SDI path) or to the SDI clock (using the SRCs in the AES-3 path.

When using an AES-3 source without an accompanying reference, the LA-5300’s 48kHz internal clock can be used as the system reference if necessary, providing the SRC on the AES-3 input is enabled.

Whenever AES67 audio is used either on the input, the output, or both, the LA-5300 must be slaved to an externally-generated PTP clock as it cannot generate its own PTP reference.

Note - The LA-5300 is set to operate in slave mode by default. There are controls in the Sync/ QoS sub-menu of the System menu to change this should the ability to operate as a clock master be introduced in future software versions, but only Slave Only mode is currently supported.

Setting Clock Reference

Click on the Clock menu (9A). Use the dropdown menus to choose a Primary Reference Clock and a Secondary Reference Clock (9C) and, if needed, a VRef clock source (9E).

The status of the selected Primary and Secondary Reference Clocks is shown to the right of the dropdown menu (9D). The absence or presence of a signal for each input type along with the format, resolution, and frame rate for incoming SDI signals is shown in the Input Status section (9B).

Figure 9 - Clock reference

GPI/O

LA-5300 offers five GPI and five GPO functions through its rear panel DB-15 connector, activated by a momentary contact closure.

GPI/O Pinout

Pin	Function	Pin	Function
Pin 1	+5VDC	Pin 9	+5VDC
Pin 2	GPI 1	Pin 10	GPO 1
Pin 3	GPI 2	Pin 11	GPO 2
Pin 4	GPI 3	Pin 12	GPO 3
Pin 5	GPI 4	Pin 13	GPO 4
Pin 6	GPI 5	Pin 14	GPO 5
Pin 7	Ground	Pin 15	Status OK
Pin 8	Ground

Figure 10 - GPI/O pinout

GPI/O Functions

GPI functions (11A) include:

• None

• Reboot/Reset Unit

• Hardware (Relay) Bypass

• Processing/Encoding Preset

• I/O Preset

• Show Preset (Processing/Encoding + I/O presets)

GPO functions (11D) include:

• None

• GPI Passthrough

• Power Supply 1 up

• Power Supply 2 up

• Power Supply 1 down

• Power Supply 2 down

• Unit resetting

• Unit rebooting

• Unit powering down

• Unit above temperature

• Unit bypass (relay bypass) active

• Change in reference

• Primary reference clock is lost

• Secondary reference is lost

• Primary reference clock is active

• Secondary reference is active

• Internal reference is active

Figure 11 - GPI/O menu

The State Indicator (11B) for each function will light for the duration of the closure on GPIs. For GPOs, it will light for the duration of the active event.

At this time, there are no user-defined Parameters (11C) associated with any GPI or GPO. Should functions with such parameters be included in future software releases, they will appear in a dropdown menu.