Unable to use reliably all four inputs of Decklink Duo 2

Hi,

We have an encoder product that currently supports all Decklink cards and Intensity Pro. I am trying to support the Decklink Duo 2 with 4 HD-SDI inputs. Therefore I use bmdDeckLinkConfigDuplexMode to set the two devices to half duplex mode, and assign a connector to each of the 4 subdevices.

Thereafter, when I read from two subdevices, I have no problem. I have no problem whichever the two subdevices I choose, even if the subdevices are on the same device. So I think the problem is not related to the half duplex mode, nor to the inputs which are all correct.

When I read from three subdevices, and worse with four devices, I regularly receive the flag bmdFrameHasNoInputSource, like every second, and a few black frames. Also the reception of frames shows a lot of jitter. Again, the source has no problem if I only use two subdevices.

Has anyone used the Duo 2 as a 4-input card ? How can I debug the issue ?

[Nicholas Gill]

Hi Christophe,

Could you please advise the motherboard manufacturer and model, and the specific slot in which the DeckLink Duo 2 is connected?

Based on the description given, my first guess would be a resource issue, either PCIe bandwidth or CPU when processing more than two inputs.

Cheers,

-nick

We're using it in a Dell PowerEdge R210 II, in the unique PCIe slot.
The CPU is: Intel(R) Xeon(R) CPU E31230 @ 3.20GHz
lspci:
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 Processor Family DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev a4)
00:1f.0 ISA bridge: Intel Corporation C202 Chipset Family LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family SATA AHCI Controller (rev 04)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 04)
01:00.0 Multimedia video controller: Blackmagic Design Device a140
02:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
02:00.1 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
03:03.0 VGA compatible controller: Matrox Electronics Systems Ltd. MGA G200eW WPCM450 (rev 0a)

Is there any way to confirm the resource contention, with counter or debug logs?

[Nicholas Gill]

Hi Christophe,

The system documentation [1] indicates that the socket is PCIe x16, so it should have sufficient PCIe bandwidth, my only remaining thought is to perhaps check for spikes in cpu utilisation during 2, 3, and 4 input captures, and possibly to test the same DeckLink device in different hardware.

The Intel Performance Counter Monitor suite has a PCIe utilisation utility, however the necessary counters are not likely to be available on the Xeon E3 cpu in the described system [2].

Cheers,

-nick

[1] https://www.dell.com/downloads/global/products/pedge/en/poweredge-r210-ii-technical-guide.pdf
[2] https://software.intel.com/en-us/articles/intel-performance-counter-monitor