2.4.12 HDR Functionality

HDR capture and playback is supported by certain DeckLink devices such as the DeckLink 4K Extreme 12G. The IDeckLinkVideoFrameMetadataExtensions object interface provides methods to query metadata associated with a video frame. The IDeckLinkVideoFrameMutableMetadataExtensions object interface provides methods to set metadata items associated with a video frame.

2.4.12.1 CEA/SMPTE Static HDR Capture

When capturing CEA Static HDR Metadata from an HDMI source, an application should first write to the HDMI EDID with the supported dynamic range standards. This can be achieved with the following steps:

• Obtain a reference to the IDeckLinkHDMIInputEDID interface from IDeckLink via IUnknown::QueryInterface().

• Configure the supported dynamic range standards by calling IDeckLinkHDMIInputEDID::SetInt() with configuration item bmdDeckLinkHDMIInputEDIDDynamicRange with one or more values defined by BMDDynamicRange.

• Write the supported dynamic range EDID value to DeckLink hardware by calling IDeckLinkHDMIInputEDID::WriteToEDID().

An application performing capture of video frames with CEA/SMPTE Static HDR Metadata should perform the following steps:

• Check that CEA/SMPTE Static HDR metadata is supported by the target by calling IDeckLinkProfileAttributes::GetFlag() with attribute BMDDeckLinkSupportsHDRMetadata.

• IDeckLinkInput::EnableVideoInput()

• IDeckLinkInput::SetCallback()

• IDeckLinkInput::StartStreams()

While streams are running:

• Receive calls to IDeckLinkInputCallback::VideoInputFrameArrived().

Inside the callback:

• Check that video frame has HDR Metadata by ensuring IDeckLinkVideoFrame::GetFlags() has bmdFrameContainsHDRMetadata flag.

• Call IUnknown::QueryInterface() on the IDeckLinkVideoInputFrame object with IID_IDeckLinkVideoFrameMetadataExtensions.

• IDeckLinkVideoFrameMetadataExtensions::Get* methods can be called to access HDR Metadata items. See BMDDeckLinkFrameMetadataID enumerator for a full list of supported HDR Metadata items.

• The IDeckLinkVideoFrameMetadataExtensions object must be released by the caller when no longer required.

2.4.12.2 CEA/SMPTE Static HDR Playback

In order to output CEA/SMPTE Static HDR metadata, your application can either provide the API with a custom video frame metadata object which implements the IDeckLinkVideoFrameMetadataExtensions interface, or by setting each metadata item on the IDeckLinkVideoFrameMutableMetadataExtensions interface associated with the IDeckLinkVideoFrame interface.

An application performing output with CEA/SMPTE Static HDR metadata should perform the following steps:

• Check that CEA/SMPTE Static HDR metadata is supported by the target by calling IDeckLinkProfileAttributes::GetFlag() with attribute BMDDeckLinkSupportsHDRMetadata.

• IDeckLinkOutput::EnableVideoOutput()

• IDeckLinkOutput::SetScheduledFrameCompletionCallback()

Create a video frame for output:

• Call either IDeckLinkOutput::CreateVideoFrame() or IDeckLinkOutput::CreateVideoFrameWithBuffer(), revealing the presence of HDR metadata by setting frame flag bmdFrameContainsHDRMetadata.

An application can set frame metadata directly to the output frame with the following steps:

• Obtain a reference to the IDeckLinkVideoFrameMutableMetadataExtensions interface from IDeckLinkMutableVideoFrame via IUnknown::QueryInterface().

• Call IDeckLinkVideoFrameMutableMetadataExtensions::Set* methods to set HDR metadata items. See BMDDeckLinkFrameMetadataID enumerator for a full list of supported HDR metadata items.

While more frames or audio need to be pre-rolled:

• Output the video frame with IDeckLinkOutput::ScheduleVideoFrame().

When sufficient frames have been pre-rolled:

• IDeckLinkOutput::StartScheduledPlayback()

While playback is running:

• Schedule more custom video frames from IDeckLinkVideoOutputCallback::ScheduledFrameCompleted().

Tip

Instead of accessing the IDeckLinkVideoFrameMutableMetadataExtensions interface, applications can provide queryable frame metadata to the API by implementing the IDeckLinkVideoFrameMetadataExtensions interface and associating to the output video frame by calling IDeckLinkMutableVideoFrame::SetInterfaceProvider().

2.4.12.3 Dolby Vision^® Playback

In order to output Dolby Vision, applications must provide video frames that specify Dolby Vision metadata. This can be achieved with the following steps:

• Call either IDeckLinkOutput::CreateVideoFrame() or IDeckLinkOutput::CreateVideoFrameWithBuffer(), revealing the presence of Dolby Vision metadata by setting frame flag bmdFrameContainsDolbyVisionMetadata.

• Obtain a reference to the IDeckLinkVideoFrameMutableMetadataExtensions interface from IDeckLinkMutableVideoFrame via IUnknown::QueryInterface().

• Provide the Dolby Vision metadata by calling IDeckLinkVideoFrameMutableMetadataExtensions::SetBytes() with the metadata ID parameter bmdDeckLinkFrameMetadataDolbyVision. Desktop Video implements Dolby Vision HDMI Transmission, it does not however depend upon the structure of this data. Details concerning the structure can be found in the Dolby Vision Display Management metadata specification by contacting Dolby.

• Provides the frame colorspace by calling IDeckLinkVideoFrameMutableMetadataExtensions::SetInt() with the metadata ID parameter bmdDeckLinkFrameMetadataColorspace.

An application performing output with Dolby Vision should perform the following steps:

• Check that the supported Dolby Vision version of the connected HDMI sink is compatible with the Dolby Vision metadata by calling IDeckLinkStatus::GetFloat() with status item bmdDeckLinkStatusSinkSupportsDolbyVision.

• Check if Dolby Vision is supported for the desired video mode with IDeckLinkOutput::DoesSupportVideoMode() called with bmdSupportedVideoModeDolbyVision.

• Configure the source colorspace of the output conversion pipeline by calling IDeckLinkConfiguration::SetInt() with configuration item bmdDeckLinkConfigVideoOutputConversionColorspaceSource with a BMDColorspace value that matches the colorspace of the output frame.

• Configure the destination colorspace of the output conversion pipeline by calling IDeckLinkConfiguration::SetInt() with configuration item bmdDeckLinkConfigVideoOutputConversionColorspaceDestination with bmdColorspaceDolbyVisionNative.

• Configure the Dolby Vision Content Mapping version by calling IDeckLinkConfiguration::SetFloat() with configuration item bmdDeckLinkConfigDolbyVisionCMVersion.

• Configure the Dolby Vision mastering monitor luminance by calling IDeckLinkConfiguration::SetFloat() with configuration items bmdDeckLinkConfigDolbyVisionMasterMinimumNits and bmdDeckLinkConfigDolbyVisionMasterMaximumNits.

• Call IDeckLinkOutput::EnableVideoOutput() with video output flag bmdVideoOutputDolbyVision. The output will switch to Dolby Vision once the first frame is displayed.

• If output callbacks are required, call IDeckLinkOutput::SetScheduledFrameCompletionCallback() with a class that implements IDeckLinkVideoOutputCallback.

While more frames or audio need to be pre-rolled:

• Output the created video frames with IDeckLinkOutput::ScheduleVideoFrame().

When sufficient frames have been pre-rolled:

• IDeckLinkOutput::StartScheduledPlayback()

While playback is running:

• Schedule more video frames with IDeckLinkOutput::ScheduleVideoFrame(). This can be called within the IDeckLinkVideoOutputCallback::ScheduledFrameCompleted() callback context or otherwise.

Dolby, Dolby Vision, and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation.