Solutions for HLG Video Capturing

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shinIngs

  • Posts: 1
  • Joined: Fri Aug 20, 2021 8:03 am
  • Real Name: GyeongIk Shin

Solutions for HLG Video Capturing

PostMon Aug 23, 2021 7:43 am

Hello, there.

I'm Ings

How do you guys deal with (10 bits + Rec.2020 + HLG signal)?

I've been tough time with capturing HLG signal through "DeckLink quad HDMI Recorder"

I have already checked some examples "Capture, CaputreStils, CapturePreview and Video Capturing with OpenCV" under SDK directory. and, as the example does, I can successfully take the BRGA32 capture image though. (with 8 bit YUV video camera)

Thank you in advanced.
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Cameron Nichols

Blackmagic Design

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  • Joined: Mon Sep 04, 2017 4:05 am

Re: Solutions for HLG Video Capturing

PostFri Sep 10, 2021 1:12 am

Hi Shin,

To access HDR metadata and Colorspace data from incoming frame: firstly in the IDeckLinkInputCallback::VideoInputFrameArrived callback, on the the received frame call IDeckLinkVideoInputFrame::QueryInterface[1] with REFIID = IID_IDeckLinkVideoFrameMetadataExtensions[2].

With the output IDeckLinkVideoFrameMetadataExtensions[2] object, call IDeckLinkVideoFrameMetadataExtensions::GetInt[3] with metadata ID bmdDeckLinkFrameMetadataHDRElectroOpticalTransferFunc[4] to access EOTF (HLG = 3).

Similarly you can access the colorspace of the input frame by calling IDeckLinkVideoFrameMetadataExtensions::GetInt[3] with metadata ID bmdDeckLinkFrameMetadataColorspace[4]. Check that the output ID is bmdColorspaceRec2020[5].

The CapturePreview SDK sample demonstrates reading the HDR metadata and Colorspace from the incoming frame.

Regards
Cameron

References (DeckLink SDK Manual):
[1] 1.2.1.1 IUnknown::QueryInterface method
[2] 2.5.43 IDeckLinkVideoFrameMetadataExtensions Interface
[3] 2.5.43.1 IDeckLinkVideoFrameMetadataExtensions::GetInt method
[4] 3.62 Frame Metadata ID
[5] 3.66 Colorspace

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