Inside Macintosh: QuickTime Components /

Chapter 11 - Clock Components / Clock Components Reference

Clock Component Functions / Managing the Time

ClockRateChanged

The Movie Toolbox calls your component's ClockRateChanged function whenever the callback's time base rate changes. The Movie Toolbox calls this function only if the qtcbNeedsRateChanges flag is set to 1 in the callBackFlags field of the callback header structure in the QTCallBackHeader structure allocated by your clock component (see "Data Type" beginning on page 11-5 for more information about the callback header structure).

pascal ComponentResult ClockRateChanged (ComponentInstance aClock,
                                          QTCallBack cb);

aClock

Specifies the clock for the operation. Applications obtain this identifier from the Component Manager's OpenComponent function.

cb

Specifies the callback for the operation. The Movie Toolbox obtains this value from your component's ClockNewCallBack function (described on page 11-9).

DESCRIPTION

The Movie Toolbox calls this function once for each qualified callback function associated with the time base. Note that the Movie Toolbox calls this function only for callback events that are currently scheduled.