Decklink Genlock input callback?

I am planning to use the genlock input of an 8k Pro Decklink card to Synchronize a c++ application.

Using the Decklink sdk, I see in the examples that there are frame arrived callbacks I can use.

Can I do this with only genlock connection? Or do I need camera feed and a reference input?

Is there a callback for the sync pulse arrival?

At its most basic, I want to trigger an event every time a new genlock pulse arrives.

Thanks!

[Cameron Nichols]

Hi Ben,

The genlock reference input impacts the timing of the SDI output. To get a callback close to the timing of the reference, you will need to schedule playback, as per high level overview in section 2.4.2 in the DeckLink SDK Manual. You can just output unmodified (black) frames created by IDeckLinkOutput::CreateVideoFrame.

Choose an output video mode close to the reference input mode. You can check status item bmdDeckLinkStatusReferenceSignalMode to determine the detected reference mode. After video output is enabled, but before scheduled playback is started, wait on status flag bmdDeckLinkStatusReferenceSignalLocked to ensure output is locked to reference.

Implement the IDeckLinkVideoOutputCallback interface to provide a frame-level callback on IDeckLinkVideoOutputCallback::ScheduledFrameCompleted. This callback will occur soon after the frame boundary of the output signal.

Regards
Cameron