Inside Macintosh: QuickTime Components /

Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

Video Digitizer Component Functions / Utility Functions

VDGetPreferredTimeScale

The VDGetPreferredTimeScale function allows an application to determine a digitizer's preferred time scale.

pascal VideoDigitizerError VDGetPreferredTimeScale 
                                 (VideoDigitizerComponent ci, 
                                  TimeScale *preferred);

ci

Identifies the application's connection to the video digitizer component. An application obtains this value from the Component Manager's OpenComponent function.

preferred

Contains a pointer to a time scale structure. The video digitizer returns information about its preferred time scale.

DESCRIPTION

Apple's sequence grabber component uses this function to establish the time scale of the media that it creates from the digitizer's output. This is especially beneficial for digitizers that return compressed data, because it allows these digitizers to timestamp the frames very accurately.

If the digitizer does not have a preferred time scale, it returns a result code of digiUnimpErr.

RESULT CODES

noErr	0	No error
qtParamErr	-2202	Invalid parameter value

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