VDDone(IM: QC)

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Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Controlling Digitization

VDDone
You can use the VDDone function in your application to determine if
the VDGrabOneFrameAsync function is finished with a specific output buffer (VDGrabOneFrameAsync is described in the previous section). Applications that use
the VDGrabOneFrameAsync function to digitize video frames should call VDDone before working with a digitized image.
pascal long VDDone (VideoDigitizerComponent ci, short buffer);
ci
Specifies the video digitizer component for the request. Applications obtain this reference from the Component Manager's OpenComponent function.
buffer
Identifies the buffer for the operation. The value of this parameter must correspond to a valid index into the list of buffers you supply when your application calls the VDSetupBuffers function (which is described on page 8-54). Note that this value is zero-based (that is, you must set this parameter to 0 to refer to the first buffer in the buffer list).

DESCRIPTION
If the VDDone function returns a 0 result, the video digitizer component has not finished the specified asynchronous frame grab. If the result is nonzero, the frame has been processed and the application can proceed to use the contents of the specified buffer.
Applications can determine whether a video digitizer component supports asynchronous frame grabbing by examining the output capability flags of the
digitizer component. Specifically, if the digiOutDoesAsyncGrabs flag is set to 1,
the digitizer component supports the VDGrabOneFrameAsync and VDDone functions. Applications can use the VDGetCurrentFlags function to retrieve the component's output capability flags. See page 8-25 for a description of the VDGetCurrentFlags function.
The VDDone function returns a long integer indicating whether the specified asynchronous frame grab is complete. If the returned value is 0, the video
digitizer component is still working on the frame. If the returned value is nonzero,
the digitizer component is finished with the frame and the application can perform its processing.