Application Fails to Work After Upgrading to 10.4 Driver.

Hi,
I developed an application to record 1080p60 video with Decklink Studio 4k + Desktop Video version 10.1 which comes in the CD together with the card.
However, after upgrading the Desktop Video to version to 10.4, the application stops working and there's valid HDMI signal. However, the Media Express works just fine which means the hardware is still working.

[Nicholas Gill]

Hi Chris,

Could you please advise the video mode and pixel format (RGB/YUV) of the video source, and the video mode and pixel format passed to EnableVideoInput [1]?

Note that both must match for the capture to be successful. The DeckLink Studio 4K supports input format detection [2], which can be used to automatically detect the input video mode and pixel format, and restart capture in the detected mode.

Please see the AutomaticModeDetection example for a demonstration of how the input video mode is detected, and the Capture/CapturePreview samples in the SDK which demonstrate how capture can be restarted with the detected video mode and pixel format.

Note that previous versions did not natively support RGB, and always performed the lossy conversion from RGB to YUV. With the addition of deep-colour support the cards will capture an RGB input as RGB.

Cheers,

-nick

[1] 2.5.4.4 IDeckLinkInput::EnableVideoInput method
[2] 2.4.6 Automatic Mode Detection

Hi Nick,
Thanks for the response.
The problem is indeed caused by the pixel format issue. i.e: HDMI input is in RGB mode, and the application is expecting a YUV format for displaying & encoding.

1. Any sample code available in the SDK for converting RGB to YUV.
2. Any Blackmagic hardware device which can be used to convert RGB to YUV? We need a fast conversion as we are displaying & encoding 60fps at the same time. Software conversion in the application may cause delay.

[Nicholas Gill]

Hi Chris,

The IDeckLinkVideoConversion[1] interface in the SDK can be used to convert between RGB and YUV frame data.

To convert the frame data, create a new IDeckLinkVideoFrame (e.g. using IDeckLinkOutput::CreateVideoFrame) with the appropriate parameters (matching frame size, pixel format set to YUV) for the desired destination format.

Then pass the source frame and destination frame to IDeckLinkVideoConversion::ConvertFrame to convert the frame data from RGB to YUV.

Please see the DeckLink SDK Windows Sample 'SignalGenerator', in SignalGeneratorDlg.cpp, function CSignalGeneratorDlg::CreateBlackFrame for an example of how the IDeckLinkVideoConversion interface is used.

The IDeckLinkVideoConversion interface uses SIMD accelerated conversions, for even lower latency it would also be possible for your application to implement GPU accelerated RGB to YUV conversion.

Cheers,

-nick

[1] 2.5.25.5 IDeckLinkVideoConversion Interface