Help! New 4k: sound fine, res+freq fine, all black pixels


I acquired a new 4K (shipped firmware version 3.1.0 as I recall) from a UK company last week. No matter what I seem to do, sound from it is fine, but I get uniformly black (or, if I go to a full colour space, dark grey) pixels. The monitoring application downloaded from site shows the expected input resolution, frame rate, and pixel format, so clearly quite a lot of the video decode is working.

Things I’ve tried:

  • Different computers. Two laptops (both recent Dell Inspirons with Intel USB chipset - exact details on request) and one 5yo desktop. No difference in behaviour.
  • Different operating systems. Desktop is Windows 7 Pro, current patching; one laptop is Windows 8.1 Pro; slightly out of date on patches; other laptop is Windows 10 1803, current patching. No difference in behaviour.
  • Different sources. Canon EOS 5D Mk III and, when I couldn’t persuade that to work, my Google Chromecast. No difference in behaviour.
  • USB2 and USB3 connections. No difference in behaviour.
  • Firmware update to v4.0.0. No difference in behaviour.
  • Computer restart. No difference in behaviour.
  • Different capture applications: OBS (latest download) and UVCap (ditto). No difference in behaviour.

I was aiming to use this for filming a band gig last Saturday (failed); its key job, and the reason I purchased it, is a live stream of an event that can’t be re-staged on Wednesday evening UK time. Ideas for how to persuade the unit to work, or where I’ve got the configuration wrong, would be gratefully received. I don’t know whether the unit’s at fault, or (probably more likely) PEBKAC.

Thanks in advance for advice, suggestions, or commiserations.

  • Peter


Resolved - many thanks to George Herbert at Epiphan. As I suspected, the problem existed between the keyboard and chair.

For others who encounter the same problem:

  • Don’t use a Chromecast as a test input! Its output is always copy-protected via HDCP, so the frame grabber will always show a black output.
  • Do make absolutely sure your HDMI input is actually displaying something. It turns out that neither my camera output nor my second HDMI out from the laptop were sending anything. A spare monitor with an HDMI input really is your friend.

I’ll now go and wipe the egg off my face and enjoy using the kit.