Controlling Digitization
This section describes the video digitizer component functions that allow applications to control video digitization. Video digitizer components allow applications to start and stop the digitizing process. Your application can request continuous digitization or single-frame digitization. When a digitizer component is operating continuously, it automatically places successive frames of digitized video into the specified destination. When a digitizer component works with a single frame at a time, the application and other software, such as an image compressor component, control the speed at which the digitized video is processed.You can use the
VDSetPlayThruOnOfffunction in your application to enable or disable digitization. When digitization is enabled, the video digitizer component places digitized video frame into the specified destination continuously. The application stops the digitizer by disabling digitization. This function can be used with both destination options.Alternatively, your application can control digitization on a frame-by-frame basis. The
VDGrabOneFrameandVDGrabOneFrameAsyncfunctions digitize a single video frame;VDGrabOneFrameworks synchronously, returning control to your application when it has obtained a complete frame, whileVDGrabOneFrameAsyncworks asynchronously. TheVDDonefunction helps you to determine when theVDGrabOneFrameAsyncfunction is finished with a video frame. Your application can define the buffers for use with asynchronous digitization by calling theVDSetupBuffersfunction. Free the buffers by calling theVDReleaseAsyncBuffersfunction.The
VDSetFrameRatefunction allows applications to control the digitizer's frame
rate. TheVDGetDataRatefunction returns the digitizer's current data rate.
Subtopics
- VDSetPlayThruOnOff
- VDGrabOneFrame
- VDSetupBuffers
- VDReleaseAsyncBuffers
- VDGrabOneFrameAsync
- VDDone
- VDSetFrameRate
- VDGetDataRate
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