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AllocVideoBuffer

Allocate a video overlay buffer of specific dimensions and pixel format.

Declaration

GA_buf * NAPI GA_videoFuncs::AllocVideoBuffer(
N_int32 width,
N_int32 height,
N_int32 format)

Prototype In

snap/graphics.h

Parameters

width | Width of the video overlay window in pixels
height | Height of the video overlay window in pixels
format | Pixel format for the input data (GA_VideoBufferFormatsType)

Return Value

Pointer to allocated video overlay buffer, NULL on failure.

Description

This function allocates a hardware video overlay buffer in offscreen video memory with the given dimensions and pixel format. The video overlay window dimensions are used by the driver to determine the stretch factor required to interpolate the input video data to the video output window on the display screen. The format parameter is used to determine the pixel format of the input bitmap data stored in offscreen video memory by the application. The video input formats flags supported are defined by GA_VideoBufferFormatsType. The calling application should check the VideoWindows member of the GA_modeInfo structure for the hardware video overlay window capabilities of the graphics hardware for a specific display mode. This function will fail if the application requests an unssupported format or if the requested features are not available for the device installed in the machine. This function will also fail if the maximum number of video overlay buffers supported by the hardware have already been allocated.

See Also

AllocVideoBuffer, FreeVideoBuffer, SetVideoOutput, SetVideoColorKey, StartVideoFrame, EndVideoFrame

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