HOW TO: Trigger SCTE-35 with OnTheAir Video 4


To trigger SCTE, you will need:

  • a valid license of OnTheAir Video 4, (OnTheAir Video Express is not supported), as well as the CC option
  • a video device that supports to output VANCs (all recent cards that we support and that have a SDI output should work fine, but older models of Blackmagic devices may not support it). Note that for AJA cards, you need to enable VANCs in AJA Control Panel.

Note that we write the SCTE info in the VANC of an SDI output, so this will only work with an SDI output. When using the direct link (for example to send video from one of our playout application to another), the SCTE info is preserved.

There are two ways to trigger SCTE:

  • with the SCTE trigger embedded in an MXF file
  • with an Action on OnTheAir Video


SCTE embedded in an MXF file

You can embed the SCTE info in a MXF file containing special VANCs of DID 0x41 and SDID 0x07. Those triggers will be passed on to the SDI output signal.

The advantage of this solution is that the SCTE trigger will always follow the video file. There will be nothing to do, but it may be complex to generate.


Trigger SCTE using Actions

An Action in OnTheAir Video is a "Secondary Event". An Action is in fact an AppleScript that can be triggered at any moment of a video file using the inspector of OnTheAir Video.

Here is an example of an Action that will do a SCTE trigger:

on Action(parameter)
     tell application "OnTheAir Video"
        send SCTE trigger splice_insert_type "spliceStart_normal" splice_event_id 32 unique_program_id 48
    end tell
end Action

Interestingly enough, the action is sent to OnTheAir Video itself (so the application is sending an AppleScript to itself).


About Event ID

You can set the event ID in the Action. If it is not specified, it will be automatically incremented, starting at zero when the application starts.


About the Splice types

Depending on the command to be sent, the "splice_insert_type" property can have a value of:

  • splicestart_normal
  • splicestart_immediate
  • spliceend_normal
  • spliceend_immediate
  • splice_cancel

Please see SCTE documentation for the various splice commands.

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