Gets or sets the rate at which time progresses for a Timeline object, relative to its parent.
A finite value greater than 0 that specifies the rate at which time progresses for this timeline, relative to the speed of the timeline's parent. If the timeline is a root timeline, this property specifies the default timeline speed. The value is expressed as a factor where 1 represents normal speed, 2 is double speed, 0.5 is half speed, and so on.
This property is read/write. The default value is 1.
Momentary or nonlinear apparent speed changes to animations can be accomplished by using spline animations.