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Configure timecode (LTC)

Linear Timecode (LTC) is a clock stream that can be supplied in a number of ways. It is typically used for synchronization in video production, filmmaking, and live events.

We can use it to facilitate automated execution of Cue Actions, through the Pixotope Event System. If we feed multiple engines the same Timecode signal, they will all trigger at the same time - imperative when frame-perfect accuracy is required, for instance for hitting lip sync or matching audio cues!

LTC can also be used to synchronise video and tracking together, or when recording incoming tracking data.

We receive an LTC signal through the video card, either:

  • via an LTC port (as analog audio on a breakout cable) OR

  • via an SDI input (embedded into the video signal)

In a production environment, this signal would usually come from audio, especially if events had to be triggered on audio playback cues. However, we can easily set up a test environment where we generate and handle our own timecode.

Supported methods

Table of supported methods




Uses the first embedded source available




Analog audio via:

  • the LTC in breakout cable (Kona 4/5)

  • the Genlock/LTC SDI connector (Corvid series)

x (LTC Port)


Analog audio via:

  • SDI connector on an auxiliary header cable (Corvid series)




Embedded in the SDI stream

x (RP188 LTC, RP188 VITC)



Embedded in the SDI stream

x (RP188 VITC)


Embedded in the SDI stream

x (RP188 VITC)

Setup Analog audio timecode

Setup for AJA video cards

AJA Kona 4 and 5

For the Kona 4 and Kona 5 cards, analog audio timecode can be received on the “LTC In” cable on the multifunction breakout cable. 

The state of the Timecode can be seen on the AJA ControlPanel, by viewing the Timecode tab and selecting the source as “LTC Port”. if timecode is received, it is displayed in the control panel.*

*Note the timecode display does not update in real-time, but refreshes every second.


For the CORVID video cards there is a joint Genlock/LTC In analog connector. 

Pixotope does not genlock to Timecode and always requires a genlock reference as analog black/burst or tri-level, or to genlock from an SDI input reference signal. 

We suggest for the Corvid cards it is easier to genlock to an SDI input and to reserve the “genlock/LTC In” input for LTC.

N.B. It is possible to construct an auxiliary LTC input cable that connects to header pins on the Corvid series of cards if you need to use both analog genlock and analog LTC concurrently.

Testing LTC Input

It is very simple to set up an LTC source. You need:

  • Windows computer with a headphone audio output

  • Source audio file 

  • Program to playback the file 

  • An audio cable from a 3.5mm plug to a BNC connector

We suggest you plug in your headphones to the audio output to verify the signal. Test first that you can hear Windows alert sounds. You may need to adjust the Windows audio mixer controls.

  1. Create or download an audio LTC file

  2. Select a program to playback the file

    • Windows Media Player is sufficient. You could also use Audacity:

    • Play one of these LTC files back through the headphones - the sound should “warble” quite loudly - timecode has a very distinctive sound

  3. Connect the audio cable

    • Connect the audio cable from the headphone output jack to the “LTC In” connector of your AJA card

  4. Open the AJA ControlPanel

    • Select the Timecode tab and set the source to “LTC Port”

      • Ensure that the Capture block is showing the correct timebase, and change it if necessary

  5. Play the file

    • Play the LTC file again and check that the timecode display is showing the correct value in the AJA ControlPanel

If the correct timecode can be shown in the AJA ControlPanel, Pixotope will be able to access the LTC values.

Windows Media Player can run the LTC .wav file by just right-clicking on the .wav file. If you want more control or to adjust or trim the signal, then we suggest using Audacity.

Troubleshooting LTC Audio

Run the LTC input:

  • If the timecode isn’t shown in Pixotope, check that the timecode is shown in the AJA ControlPanel

  • If it is not shown in the AJA ControlPanel, check that “LTC Port” is selected and that the sync rate of the Capture block matches the LTC file rate

  • If it still doesn’t work, check the audio output of the source computer on headphones. Is it warbling like timecode? Is it loud?

  • If it sounds incorrect, or you have no sound, check the Windows Audio Mixer options or try a different LTC file

  • If it doesn’t appear to playback in Audacity, check with Windows Media Player

Connecting Audio LTC to Multiple Pixotope Engines

The AJA Kona 4 and Kona 5 cards have an “LTC In” and an “LTC Out” cable, so that Audio LTC could be looped through one machine to the next in a “daisy-chained” configuration.

This is not the best way, however, because any break in that chain could stop the downstream machines from receiving the LTC signal.

A better approach is to distribute the LTC signal through an audio distribution amplifier (d/a), and provide a separate cable from the d/a to each of the “LTC In” ports of the AJA cards.

Set up timecode in Director

  1. Go to SETUP > Configure > Routing

  2. Click on "Timecode" in the top-right corner of a machine

  3. A Timecode item will be added underneath Genlock

  4. Launch a level as Timecode is reported from the running engine

  5. Set your Primary source and its Status field appears

    The Status field shows the timecode received by the engine

    • For AJA, you can also verify that timecode is received, by viewing the Timecode tab of the AJA ControlPanel

      • Embedded LTC: set source to "RP188 LTC" or "RP188 VITC"

      • LTC Port: set source to "LTC Port"

  6. Optionally set your Secondary source and its Status field will appear

  7. Repeat these steps for all machines which need a timecode source

Only one Embedded source is possible at any time.

A level needs to be running for Status to update as the timecode is reported by the engine.

Using timecode in Editor

  1. Access the timecode using the "Get Video IO Timecode" blueprint node

    • the index refers to primary or secondary within Director

Outputting timecode via SDI

Timecode is embedded in all SDI outputs.

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