Quad 2 running at 10fps

Hello,

a client has a Quad 2 and has some cameras connected running at 1080p50. In our software using the DeckLink SDK the view is flickering like crazy. Digging into this revealed that the DeckLink card is sending updates (calling VideoInputFrameArrived) at pretty much exactly 10fps. I cannot see any reason why the frame rate should be limited to 10fps.

It doesn't feel like it's a performance or bandwidth issue as it's stable even if only one camera is attached. The CPU is idling (none of the 20 cores > 20%).

This is using the latest 12.4.2 SDK on Ubunutu 22.

The Decklink card is in a PCIe slot that reports as x4 5GT/s. That's not ideal but the bandwidth should still be around 2GB/s at x4, which should be plenty for a single 1080p50 camera.

The cameras are streaming YUV10bit.

Does anyone have any idea what we might be doing wrong?
Am I missing any relevant information?


cheers,
nils

Hello,

putting the DeckLink card into a different PCIe slot helped. We're sourcing a different mainboard now.

The thing that still stumps me is the exact 10fps it was delivering. There must be some logic in the driver that throttles frame rate. Is there any way I can figure that out through the SDK?

I saw the status properties:

bmdDeckLinkStatusPCIExpressLinkSpeed
bmdDeckLinkStatusPCIExpressLinkWidth

but that doesn't tell me what the particular card requires. I can go on the website and check the specs for all capture cards and hardcode them but that's probably not an ideal solution.

Is there a way to ask the driver/SDK whether the card is throttled?


thanks,
nils