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CVDisplayLinkOutputCallback

A type for a display link callback function that the system invokes when it’s time for the app to output a video frame.

Declaration

typealias CVDisplayLinkOutputCallback = (CVDisplayLink, UnsafePointer<CVTimeStamp>, UnsafePointer<CVTimeStamp>, CVOptionFlags, UnsafeMutablePointer<CVOptionFlags>, UnsafeMutableRawPointer?) -> CVReturn

Parameters

  • displayLink:

    A display link that requests a frame.

  • inNow:

    A pointer to the current time.

  • inOutputTime:

    A pointer to the display time for a frame.

  • flagsIn:

    Currently unused. Pass 0.

  • flagsOut:

    Currently unused. Pass 0.

  • displayLinkContext:

    A pointer to app-defined data.

Discussion

Your app must register a callback function for the system to invoke with the data necessary to process and output a frame of video. Your callback must retrieve the frame with the timestamp that the inOutputTime parameter specifies, manipulate it if you require (for example, apply color correction or map onto a surface), and output it to the display.

See Also

Callbacks