Capturing 4k@60Hz in RGB gives bad results (pics included)

We have a DeckLink4K Extreme 12G - HDMI 2.0. When we try to capture 4k@60Hz (3840x2160p60) in RGB 444 (by using the DeckLink API), the frames that we get back are incorrect. We are getting them by dumping the raw bytes from the CapturePreview SDK sample with pixelFormat set to bmdFormat8BitBGRA. The input source's top-left is as follows:



and the top-left of the image we get in the capture is



Notice that the buttons in the top-left are distorted/corrupted.

We have verified that we can send 4k@60Hz in RGB 444 to a regular display without any such problem using the same video source and hdmi cable. But the capture card always results in artifacts like these.

Dropping the refresh rate to 30Hz eliminates the problem, but we need to capture at 60Hz. If we try to do the capture directly from Blackmagic Media Express, the software will not even show the source when at 60Hz. Further, the DirectShow filters provided explicitly omit the RGB capture options in their UI when switching to 4k@60Hz.

All of this makes me wonder if 4k@60Hz in RGB is even supported. The tech specs for the card make it appear that it should be, but our experiences are proving otherwise.

I can't see your images, be we had the same issue with that card, could not get Blackmagic Media Express to 60Hz whether from an ATEM, URSA, or CION.

[Matt Jefferson]

Hello Chad and Nick

I am able to output (playback) and input (capture) on Decklink 4K extreme 12G using 10.6.4 driver at 10bit RGB at UHD 2160p60. I ran the test yesterday on both Ultrastudio 4K Extreme (12G) and Decklink 4k ext 12G between then and then just card alone going fromOutput A to Input A and both tests were successful.

Please ensure you are using SDK based application from OS>samples>bin and I used Signal Generator and Media Express. Also make sure your SDI cable is rated for 12G. We used Belden cable rated for this signal.

If you are using HDMI, ensure it is rated for UHD 2160p60 and RGB format signal rates.

If you need hardware support, please contact us via our website and support links