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Blackmagic Decklink cards

Using BlackMagic Decklink cards
Decklink-specific settings

To activate the video capture of the Decklink card, the VideoSize and VideoSubtype indexes must be set to 0, and the format must be specified by the VideoFormat index, e.g.:

VideoGrabber.VideoSubtype = 0 (default)
VideoGrabber.VideoSize = 0 (default)
VideoGrabber.VideoFormat = VideoGrabber.VideoFormatIndex ("HDYC 1920x1080 25 fps")
VideoGrabber.VideoInput = VideoGrabber.VideoInputIndex ("HDMI")
VideoGrabber.StartPreview()

Remark:
If there is no image (black video window), it is possible that the VideoFormat selected is not suitable.
To determine the proper video format, proceed as follows:
- run the pre-compiled MainDemo.exe
- select the Decklink card in the VideoDevices list
- set VideoSubtype and VideoSize to default
- select the video input in the "Video Inputs" list
- select the video format in the "Video formats" list
- start the preview
then try each one of the video formats available in the "Video Formats" list, until the captured video appears.

Playout to the decklink renderer
The VideoRendererExternal property makes it possible to activate the external renderer on the Blackmagic Decklink card.

By default TVideoGrabber resizes to 720x480.
To select the HD format, invoke UseNearestVideoSize (1920, 1080, true) before invoking OpenPlayer (to go back to the default setting invoke UseNearestVideoSize (0, 0, false))

Note that the Decklink renderer also requires a standard frame rate (e.g. 25 fps or 29.97 fps). If the clip has a non-standard frame rate it may fail to play on the Decklink output.

Specifying the Decklink renderer to use when more than one Decklink card is installed in the same PC
If more than one Decklink card is used in the same PC, specify the number of the card to use in the VideoRendererExternalIndex property (in the 0..n-1 range).