2.4.3 3D Functionality

3D (dual-stream) capture and playback is supported by certain DeckLink devices such as the DeckLink 4K Extreme. The 3D functionality is only available over HDMI or SDI, where Channel A and Channel B represent the left and right eyes. The 3D packing must be manually set when connecting to pre-HDMI 1.4 devices. When capturing from an HDMI 1.4 compliant source, the 3D packing format will automatically detected, and cannot be overridden. When outputting to an HDMI 1.4 compliant device / monitor, the packing format will be adjusted according to the device / monitor’s capabilities, but can be manually changed. Refer to the IDeckLinkConfiguration Interface and BMDVideo3DPackingFormat sections for more information on getting and setting the packing format.

Note

Automatic mode detection is not available for UHD and DCI 4K 3D dual-link SDI modes.

2.4.3.1 3D Capture

An application performing a streaming 3D capture operation should perform the following steps:

• If desired, enumerate the supported capture video modes by calling IDeckLinkInput::GetDisplayModeIterator(). For each reported capture mode, check for the presence of the bmdDisplayModeSupports3D flag in the return value of IDeckLinkDisplayMode::GetFlags() indicating that this mode is supported for 3D capture. Call IDeckLinkInput::DoesSupportVideoMode() with the bmdVideoInputDualStream3D flag to check if the combination of the video mode and pixel format is supported.

• Call IDeckLinkInput::EnableVideoInput() with the bmdVideoInputDualStream3D flag.

• IDeckLinkInput::EnableAudioInput()

• IDeckLinkInput::SetCallback()

• IDeckLinkInput::StartStreams()

While streams are running:

• Receive calls to IDeckLinkInputCallback::VideoInputFrameArrived() with left eye video frame and corresponding audio packet.

Inside the callback:

• Call IUnknown::QueryInterface() on the IDeckLinkVideoInputFrame object with IID_IDeckLinkVideoFrame3DExtensions.

• IDeckLinkVideoFrame3DExtensions::GetFrameForRightEye() The returned frame object must be released by the caller when no longer required.

• IDeckLinkInput::StopStreams()

2.4.3.2 3D Playback

To support 3D playback, your application must provide the API with a video frame 3D object which implements the IDeckLinkVideoFrame3DExtensions interface. This can be achieved by providing your own class which:

• Subclasses the IDeckLinkVideoFrame3DExtensions interface.

• Returns a pointer to itself (cast to IDeckLinkVideoFrame3DExtensions) when its IUnknown::QueryInterface() method is called with IID_IDeckLinkVideoFrame3DExtensions.

• Implements all the methods in the IDeckLinkVideoFrame3DExtensions class.

• Returns an instantiated provider object that implements IUnknown to provide the DeckLink API access to the class’ IUnknown::QueryInterface() method. Refer to the IDeckLinkMutableVideoFrame::SetInterfaceProvider() method for further information.

An application performing a streaming 3D playback operation should perform the following steps:

• Check if 3D is supported for the desired video mode with IDeckLinkOutput::DoesSupportVideoMode() called with bmdVideoOutputDualStream3D.

• Call IDeckLinkOutput::EnableVideoOutput() with the bmdVideoOutputDualStream3D flag set.

• IDeckLinkOutput::EnableAudioOutput()

• IDeckLinkOutput::SetScheduledFrameCompletionCallback()

• IDeckLinkOutput::SetAudioCallback()

• IDeckLinkOutput::BeginAudioPreroll()

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

• Create a video frame object with IDeckLinkOutput::CreateVideoFrame() or IDeckLinkOutput::CreateVideoFrameWithBuffer().

• Create a video frame 3D extensions object that subclasses IDeckLinkVideoFrame3DExtensions as explained above.

• Associate the video frame to its 3D extensions provider by calling IDeckLinkMutableVideoFrame::SetInterfaceProvider() with IID_IDeckLinkVideoFrame3DExtensions.

• IDeckLinkOutput::ScheduleVideoFrame()

• Return audio data from IDeckLinkAudioOutputCallback::RenderAudioSamples().

• When audio preroll is complete, call IDeckLinkOutput::EndAudioPreroll().

• IDeckLinkOutput::StartScheduledPlayback()

While playback is running:

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

• Schedule more audio from IDeckLinkAudioOutputCallback::RenderAudioSamples().

• If audio is not required, the call to IDeckLinkOutput::EnableAudioOutput(), IDeckLinkOutput::SetAudioCallback() and IDeckLinkOutput::BeginAudioPreroll() may be omitted.

• If pre-roll is not required initial IDeckLinkOutput::ScheduleVideoFrame() calls and the call to IDeckLinkOutput::BeginAudioPreroll() and IDeckLinkOutput::EndAudioPreroll() may be omitted.