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EnableVideoInput failure on headless machine

PostPosted: Tue Sep 10, 2019 7:17 pm
by dibbitson

I've setup an 8K Pro on a headless machine and installed the driver.

I'm getting a failure result (E_FAIL) from EnableVideoInput that I'm having trouble tracking down.

Once I installed BlackmagicDesktopVideoSetup and configured (XForwarding via SSH) the connection information this issue went away.

However for future deployment this isn't practical and I was trying to recreate whatever BlackMagicDesktopVideoSetup is doing programmatically to no avail.

I tried setting various properties via IDeckLinkConfiguration and also tried setting the profile via IDeckLinkProfileManager.

Is there something specific I need to do here?


Re: EnableVideoInput failure on headless machine

PostPosted: Wed Sep 11, 2019 6:48 am
by Cameron Nichols
Hi David,

The most likely reason for IDeckLinkInput::EnableVideoInput returning E_FAIL, is that the input resource is already tied up, either:
  • The input has been enabled by another process, or
  • The device is configured for half-duplex profile and the output is enabled. You can check the active profile by running the ActivateProfile SDK sample
It may be worth running StatusMonitor SDK example to check the busy state of the device. This will help determine whether the input or output is enabled. Refer to section 2.7.42 Device Busy State of the SDK Manual for further information.


Re: EnableVideoInput failure on headless machine

PostPosted: Wed Sep 11, 2019 7:14 pm
by dibbitson
Thanks Cameron,

I checked those things, no luck.

All subdevices are configured for half duplex according to ActivateProfile.

No other process is using the card.

StatusMonitor shows a busy state of 0.

It's not clear how to actually change whether output is enabled or not. Would you have to explicitly acquire an IDeckLinkOutput interface and DisableVideoOutput() first before proceeding with EnableVideoInput()?