Controlling Digitization8

This section describes one new video digitizer component function, VDSetDataRate , that instructs your video digitizer component to observe a specified rate of data delivery.

VDSetDataRate

The VDSetDataRate function instructs your video digitizer component to limit the rate at which it delivers compressed, digitized video data.



 
pascal VideoDigitizerError VDSetDataRate (

                     VideoDigitizerComponent ci,

                     long bytesPerSecond);

ci: Specifies the video digitizer component for the request. Applications obtain this reference from the Component Manager's OpenComponent function.
bytesPerSecond: Specifies the maximum data rate requested by the application. This parameter is set to 0 to remove any data-rate restrictions.

DISCUSSION

This function is valid only for video digitizer components that can deliver compressed video (that is, components that support the VDCompressOneFrameAsync function). Components that support data-rate limiting set the codecInfoDoesRateConstrain flag to 1 in the compressFlags field of the VDCompressionList structure returned by the component in response to the VDGetCompressionTypes function.

Your video digitizer component should return this data-rate limit in the bytesPerSecond parameter of the existing VDGetDataRate function.