- Posts: 2
- Joined: Mon May 09, 2016 3:04 pm
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.
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.
Last edited by Nick Neumann on Mon May 16, 2016 2:50 pm, edited 1 time in total.