Inside Macintosh: QuickTime Components
This section discusses the video digitizer component functions that allow applications to set the spatial characteristics of the source video signal. You can use these functions in your application to set and retrieve information about the maximum source rectangle, the active source rectangle, the vertical blanking rectangle, and the digitizer rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .
You can use the VDGetMaxSrcRect function in your application to get the size and location of the maximum source rectangle. Similarly, the VDGetActiveSrcRect function allows you to get this information about the active source rectangle, and the VDGetVBlankRect function enables you to obtain information about the vertical blanking rectangle.
You can use the VDSetDigitizerRect function to set the size and location of the digitizer rectangle. The VDGetDigitizerRect function lets you retrieve the size and location of this rectangle.
The VDGetMaxSrcRect function returns the maximum source rectangle.
pascal VideoDigitizerError VDGetMaxSrcRect
(VideoDigitizerComponent ci,
short inputStd,
Rect *maxSrcRect);
The maximum source rectangle defines the spatial boundaries of the input video signal. All other rectangles--active source rectangle, digitizer rectangle, and vertical blanking rectangle--are defined relative to the maximum source rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .
The VDGetActiveSrcRect function allows applications to obtain the size and location information for the active source rectangle used by a video digitizer component.
pascal VideoDigitizerError VDGetActiveSrcRect
(VideoDigitizerComponent ci,
short inputStd,
Rect *activeSrcRect);
The source rectangle is that area in the source video image that contains active video. The video digitizer component returns spatial information that is relative to the maximum source rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .
The VDGetVBlankRect function returns the vertical blanking rectangle.
pascal VideoDigitizerError VDGetVBlankRect
(VideoDigitizerComponent ci,
short inputStd,
Rect *vBlankRect);
The vertical blanking rectangle defines the vertical blanking area in the input video signal, and it corresponds to lines 10 through 19 of the incoming video signal. The video digitizer component returns spatial information that is relative to the maximum source rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .
The VDSetDigitizerRect function allows applications to set the current digitizer rectangle.
pascal VideoDigitizerError VDSetDigitizerRect
(VideoDigitizerComponent ci,
Rect *digitizerRect);
The current digitizer rectangle defines the area that the digitizer component reads from the input video signal. Applications can crop the input video signal by manipulating this rectangle. The digitizer rectangle coordinates must be specified relative to the maximum source rectangle. Furthermore, the digitizer rectangle must be completely within the maximum source rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .
The VDGetDigitizerRect function returns the current digitizer rectangle.
pascal VideoDigitizerError VDGetDigitizerRect
(VideoDigitizerComponent ci,
Rect *digitizerRect);
The current digitizer rectangle defines the area that the digitizer component reads from the input video signal. The video digitizer component returns spatial information that is relative to the maximum source rectangle. For a complete discussion of the relationship between these rectangles, see "About Video Digitizer Components," which begins on About Video Digitizer Components .