How to EnableVideoInput for 4 inputs in one process?

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myzhxih

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  • Joined: Mon Sep 26, 2022 5:55 am
  • Real Name: xihanzhang

How to EnableVideoInput for 4 inputs in one process?

PostMon Sep 26, 2022 6:02 am

Hi Blackmagic,

I have a QUAD HDMI RECORDER CAPTURE product.
I want to enable 4 HDMI inputs at the same time through EnableVideoInput() in one process (application).
I have to use these four preview on one window.
Each input is 4K@50hz and the same frame rate.

But the result of deckLinkAttributes->GetInt(BMDDeckLinkVideoInputConnections, &SuptInputConn) is only 2 (SuptInputConn) on windows10 x64. Why? and how to implement my requirement?

Thanks.
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Cameron Nichols

Blackmagic Design

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  • Joined: Mon Sep 04, 2017 4:05 am

Re: How to EnableVideoInput for 4 inputs in one process?

PostFri Oct 14, 2022 11:35 am

Hi Xihanzhang,

The attribute BMDDeckLinkVideoInputConnections is returning the expected value, you will find the definition for BMDVideoConnection enum in DeckLinkAPITypes.h -
Code: Select all
bmdVideoConnectionHDMI                                       = 1 << 1,
I believe the attribute you are looking for is BMDDeckLinkNumberOfSubDevices, which will output the number of sub-devices on the card.

To enable all inputs, you will need to call IDeckLinkInput::EnableVideoInput for each sub-device. You should review the QuadPreview SDK sample for an example of multiple captures.

Regards
Cameron

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