Decklink Duo 2 FPS when input/output at the same time

edited May 14 in MAIN
We are exploring the possibility of using the Blackmagic Decklink Duo 2 PCIe cards to add additional I/O to Millumin. We have had great success with using them as inputs; however, using them as outputs poses an issue. All I/O references are 1080p@59.94

I have consistently observed an issue where the FPS of the outputs drop as low as 15fps when using multiple outputs from a single DeckLink Duo 2 card.
  • With a single input and output live on the same card the output drops to 30fps.
  • >1 input and only one output drops the output to 15-20fps.
  • One output with no inputs results in an output at 60fps.
  • 4 inputs and no (decklink) outputs results in 60fps (when using DVI out, for example).
Is this a Millumin issue or a Blackmagic issue? Are there any known solutions?


  • Hello @michaelvoccola,

    Millumin is using libraries provided by Blackmagic, so it should have the same performances as their own applications.

    However, if you're using your Decklink Duo on a chassis via Thunderbolt, having data coming in and out could be an issue. Could be : you should ask Blackmagic about this setup, since they are the only one to be able to reply about such hardware questions (if it's your case of course).

    Best. Philippe
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