Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Time Base Functions / Working With Time Base Values

SetTimeBaseRate

The SetTimeBaseRate function allows your application to set the rate of a time base.

pascal void SetTimeBaseRate (TimeBase tb, Fixed r);

tb

Specifies the time base for this operation. Your application obtains this time base identifier from the NewTimeBase function (described on page 2-297).

r

Specifies the rate of the time base.

DESCRIPTION

You can determine the number of time units that pass each second for a time base by multiplying its rate by the time scale of its time coordinate system. For example, if you set the rate of a time base to 2 and the time base has a time scale of 2, that time base passes through 4 units of its time each second.

Rates may be set to negative values. Negative rates cause time to move backward for the time base.

ERROR CODES

None

SEE ALSO

You can retrieve the rate of a time base by calling the GetTimeBaseRate function, which is described in the next section.