Blackmagic Forum

With the latest 11.6 drivers, my VideoInputFormatChanged callback is getting spammed with bmdVideoInputColorspaceChanged notifications, even though nothing is changing. This is on a Quad HDMI card. It happens for all 4 inputs, even when there is nothing connected to them.

Hi David,

Desktop Video 11.6 introduces a number of new format detection flags for color bit-depth of the incoming signal (ref DeckLink SDK manual - 3.26 Detected Video Input Format Flags):

• bmdDetectedVideoInput12BitDepth
• bmdDetectedVideoInput10BitDepth
• bmdDetectedVideoInput8BitDepth

The bmdVideoInputColorspaceChanged format changed event flag will occur if either the colorspace and/or bit-depth of the detected signal does not match that of the pixel format set on call to IDeckLinkInput::EnableVideoInput.

The Desktop Video SDK samples were updated in 11.6 to prevent persistent IDeckLinkInputCallback::VideoInputFormatChanged callbacks with one of 2 strategies:

1. For CapturePreview/QuadPreview samples, the VideoInputFormatChanged callback will honor the BMDDetectedVideoInputFormatFlags and enable vide input with a pixel format that matches the flags.
2. For samples that rely on specific pixel formats, such as FileCapture/Capture, these maintain local BMDPixelFormat variable based on the detected colorspace and only call EnableVideoInput when colorspace is changed.

Regards
Cameron