Setting up AJA video I/O devices

Reeltime supports the following video I/O devices by AJA for capturing and playback of SDI signals:

  • AJA Kona family (e.g., KONA 5):
    • up to 4 bi-directional input/output ports
    • 1.5G, 3G, and depending on model 6G and 12G SDI signals
  • AJA Io family (e.g., Io 4K Plus and Io X3)
    • up to 4 bi-directional input/output ports
    • 1.5G or 3G SDI signals
  • AJA Corvid family (e.g. Corvid 88)
    • up to 8 bi-directional input/output ports
    • 1.5G, 3G, and depending on model 6G and 12G SDI signals
  • AJA T-Tap family
    • T-Tap: 1 output port for playback of 1.5G or 3G SDI signals
    • T-Tap Pro: 1 output port for playback of 1.5G, 3G, 6G or 12G SDI signals

Configure bi-directional device ports as inputs or outputs#

You can configure your device’s bi-directional SDI ports to be used as input or as output ports within the “Devices” settings under “AJA Video I/O Configuration.”

A table displays all connected devices in a separate row, and you can choose from a range of configuration presets supported by each device.

Device-specific AJA video I/O configuration in devices settings

When you finish configuring the device ports of your AJA video I/O devices, you need to restart the application to apply your changes.

Associate device ports with input and output slots#

Within the slot manager, you can associate your AJA device’s SDI input ports with an input slot and, in the same way, SDI output ports with output slots:

  • In existing slots, you can choose from all currently available ports in the “Device” drop-down menu.
  • If you want to add a new slot, you can press the “+” button that lets you associate a device port with your new slot directly.

When configuring an input port, there are the following options:

  • Format: The video format of the incoming video signal sets the device’s video format automatically when “Video Output Format” is set to “Auto”. If you have selected a fixed video output format, make sure the output frame rate is either identical to the input or a compatible higher rate. Supported higher-rate equivalents include 23.98 → 59.94, 24 → 60, 25 → 50, 29.97 → 59.94, 30 → 60.
Tip: Using a higher output frame rate can also reduce latency, as frames are transmitted more frequently. Note that your wireless systems and monitors must support the required SDI bandwidth (3G for HD, 12G for UHD/4K). Read the blog article Latency on film sets: How to achieve the fastest possible live feeds with Reeltime to learn more.
Tip: If you experience intermittent signal loss—such as when the camera is powered off or a wireless system temporarily outputs an invalid format—setting a fixed video format helps maintain a stable and continuous output.
Note: Mixing HD and 4K formats between input and output on AJA video I/O devices is currently not supported.
  • Camera Type: Ensure that the appropriate camera type is set to receive the camera’s ANC metadata correctly and trigger recording based on the record flag embedded in the SDI signal.
  • Record Trigger: You can choose which detection method should be used to trigger the recording automatically. Note that the appropriate method depends on your setup and camera:
    • Choose “Record Flag (HANC)” to detect the record flag embedded in the horizontal ANC metadata of SDI signals from ARRI, RED, and Sony cameras.
    • Choose “RecRun Timecode” if your camera is set to use RecRun timecode and you would like to trigger recording/stop recording depending on whether the timecode is running or the timecode is stopped.
    • Choose “None” to disable the auto-record function for this camera
  • Decoding Levels: In rare cases, you can change the decoding levels from legal to full, for example, if you receive an ungraded signal from a Sony camera that outputs an SDI signal in extended range.

Slot manager with SDI device configuration for an input slot

When configuring an output port, the outgoing signals’ video formats usually derive from the input and are, therefore, not editable. However, you can set an output video format manually if you configure the device to use all ports as outputs.

Automatic pass-through#

AJA video I/O devices with at least one input and output port support the automatic pass-through option. This mechanism bypasses Reeltime’s video processing by routing camera signals directly in the AJA device for zero-added latency live monitoring.

You can enable the automatic pass-through option for any compatible output port that you configure in an output slot.

Automatic pass-through option in output slot

If automatic pass-through is enabled and the output slot shows a live signal, the mechanism automatically switches to the unprocessed direct live feed received on an input port of the same device.

If automatic pass-through is enabled and the output slot shows a playback signal, the feature switches seamlessly to the output from the application.

When you change the output slot’s source to another live input, the feature automatically continues to show a pass-through signal if the new source is from the same I/O device or seamlessly switches to the processed output from the application.

Note: For configuring two or more simultaneous pass-throughs using a single I/O device, it is important to genlock the camera signals. For example, if you want to show camera A on the director’s monitor and camera B on the script supervisor’s monitor, and both should see a pass-through signal for zero-added latency, ensure to genlock camera A and B (e.g., using an Ambient Lockit or similar device.)
Note: Automatic pass-through may not work as intended when the video output frame rate is higher than the input frame rate. For example, using 24 fps inputs with 60 fps outputs is not supported.

Pass-through on quit#

When quitting the application, a default pass-through routing from input port(s) to output port(s) is automatically applied. For example, if you have an AJA Io X3 configured for 2 inputs and 2 outputs and quit the application, the signal received on input port 1 is passed through to output port 3, and the signal received on input port 2 is passed through to output port 4.

Last updated: June 21, 2024