Inside Macintosh: QuickTime Components
You can improve the performance of frame-by-frame digitization by using multiple destination buffers for the digitized video. Your application defines a number of destination buffers to the video digitizer component and specifies the order in which those buffers are to be used. The digitizer component then fills the buffers, allowing you to switch between the buffers more quickly than your application otherwise could. In this manner, you can grab a video sequence at a higher rate with less chance of data loss. This technique can be used with both destination options.
You define the buffers to the digitizer by calling the VDSetupBuffers function (described on VDSetupBuffers ). The VDGrabOneFrameAsync function (described on VDGrabOneFrameAsync ) starts the process of grabbing a single video frame. The VDDone function (described on VDDone ) allows you to determine when the digitizer component has finished a given frame.