How to configure automatic port passthru

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  • Posts: 8
  • Joined: Thu Feb 16, 2023 7:51 pm
  • Location: Mexico
  • Real Name: Ariel Molina

How to configure automatic port passthru

PostTue Oct 03, 2023 12:32 am


I have a Decklink Studio 4K with 2 SDI connectors. I can capture on device=0 (using GStreamer or MediaExpress 1080i5994) and I get automatic video passthru on the other connector. Then when I play something on the same device, the second connector automatically switches to my playout video, smoothly getting back to Live passthru when my playout app closes. Life is perfect...

However I needed to use a different card, smaller one. So I got a Decklink Duo 2 Mini and related cables with multiple SDI connectors.

However now I cannot passthru and play on the same device=0. And wrangling on many possibilities of Desktop Video Setup I just can't find a way to reproduce the desired behavior.

The Desired Behavior is (as per current Decklink Studio 4K operation).

    1. When MyCaptureApp is running "Capturing on port A" (device 0), automatically passthru video to port B.
    2. When MyPlayoutApp starts running (targeting device 0), instantly reproduce it's playout on port B, with no disruption to MyCaptureApp.
    3. When MyPlayoutApp ends running or is killed, fallback to 1)

Port B can be Any port. Somehow I can manage to use the same device=0 on the Decklink Studio 4K but it can't be done on Decklink Duo 2 Mini.

Ultimately this works like a charm on Decklink Studio 4K, but I'm really struggling to make it work on the Decklink Duo 2 Mini. I have tested a plethora of configurations :( I only need a single capture and a single playout.

Or, is there a hardware limitation on that card? What cards/configurations are required for such a setup.

Mitra Mahmoodzadeh

  • Posts: 53
  • Joined: Wed Sep 02, 2015 2:45 pm

Re: How to configure automatic port passthru

PostTue Oct 03, 2023 8:45 pm

Hello Ariel,

Based on the SDK (please see the image bellow) I think Decklink Duo 2 Mini is not full duplex, so you cannot enable capture and render simultaneously.

But you can capture with Decklink Duo 2(SDI1) and play it with Decklink Duo 2(SDI2) port simultaneously. In this case, you may need to change the connector mapping in the Desktop Video Setup.
b1.png (165.95 KiB) Viewed 3948 times

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