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124 Chapter 3 Adding Media, Retiming, and Remastering
Parameters
The TimeX node has one parameter in the Parameters tab:
newTime
This parameter defaults to a spline that maps every input frame to a corresponding
frame in time, such that the clip plays forward normally at 100 percent speed. Typically,
you’ll enter a new expression into this field, using the expression time, to remap the
frames of the image sequence or movie file to create new timing effects.
Similar to Lookup and ColorX, you can duplicate most other Time functions with TimeX.
These other functions are simply macros that include TimeX. They are included because
TimeX can be counter-intuitive.
A more complex example is to animate 360 3D frames with an animated light. The light
is from the right at frame 0, from the top at frame 90, from the left at frame 180, and so
on. You then position a fake light source in the composite. By figuring out the angle of
the light to the 3D element (using trigonometry), you can pick one of the 360 input
frames to fake the lighting change.
Timing Expression Explanation
time-10 Shifts the clip 10 frames forward. While processing frame 50, it
reads input frame 40.
101-time Assumes frame 100 is the last frame. At frame 1, 100 used.
time%10+1 Loops every 10 frames. Takes the remainder of time/10, and adds 1
(otherwise frame 10 = 0).
time>10?10:time A conditional expression. Freezes the clip at frame 10. Any frame
before that is processed normally.
time Do nothing.
100 (or any integer) Picks one frame. In this example, at every frame, the node returns
100, so only input frame 100 is used.
time*2 Double the rate. In this expression, at frame 10, frame 20 is used.
“CSpline(0,
1@1,
30@25,
40@50,
90@75, 100@100
)”
Using a curve to speed the clip up and down.The arbitrary curve
shown here returns different frame values. You can use any spline
type, with as many keyframes as you want.
Multiple Branches
You can only have one branch traced up to the FileIn with a TimeX in it. To get
multiple time shifts on the same clip, copy the FileIn. Note also that FileIn has timing
controls of its own that you may find easier to use.