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Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Controlling Digitization

VDGrabOneFrame

The VDGrabOneFrame function instructs the video digitizer component to digitize a single frame of source video.

All video digitizer components must support this function.

pascal VideoDigitizerError VDGrabOneFrame 
                                    (VideoDigitizerComponent ci);

ci

Specifies the video digitizer component for the request. Applications obtain this reference from the Component Manager's OpenComponent function.

DESCRIPTION

The application specifies the destination for the digitized frame by calling
either the VDSetPlayThruDestination function (described on page 8-35) or the VDSetPlayThruGlobalRect function (described on page 8-39).

If the specified digitizer component is already digitizing continuously when the application calls VDGrabOneFrame, the digitizer component returns the next digitized frame and then stops. If the digitizer component is stopped, the component digitizes a single frame and then stops. To resume continuous digitization, applications should call the VDSetPlayThruOnOff function, which is described in the previous section.

The VDGrabOneFrame function supports synchronous single-frame video digitization--that is, the digitizer component does not return control to your application until it has successfully processed the next video frame. Some video digitizer components may also support asynchronous single-frame digitization. Applications can use asynchronous digitization by calling the VDGrabOneFrameAsync function, described on page 8-56.

RESULT CODE

noErr

0

No error