User Manual

Table Of Contents
Source Time
This control designates from which frame in the original sequence to begin sampling.
When a Time Stretcher node is added to the node tree, the Source Time control already
contains a Bézier spline with a single keyframe set to 0.0. The keyframe position is determined
by the current time when the node is added to the node tree.
NOTE: The Source Time spline may not be immediately visible until Edit is selected
from the Source Time’s contextual menu, or Display all Splines is selected from the
Spline Window’s contextual menu.
Interpolate Mode
This menu determines the how the time speed is processed in order to improve its visual
playback quality, especially in the case of clips that are slowed down. There are three choices
in the menu.
Nearest: The most processor efficient and least sophisticated method of processing;
frames are either dropped for fast motion or duplicated for slow motion.
Blend: Also processor efficient but can produce smoother results; adjacent duplicated
frames are dissolved together to smooth out slow or fast motion effects.
Flow: The most processor intensive but highest quality method of speed effect
processing. Using vector channels pre-generated from an Optical Flow node,
new frames are generated to create slow or fast motion effects. The result can be
exceptionally smooth when motion in a clip is linear. However, two moving elements
crossing in different directions or unpredictable camera movement can cause
unwanted artifacts.
Sample Spread
This slider is displayed only when Interpolation is set to Blend. The slider controls the strength
of the interpolated frames on the current frame. A value of 0.5 blends 50% of the frame before
and 50% of the frame ahead and 0% of the current frame.
Depth Ordering
This menu is displayed only when Interpolation is set to Flow. The Depth Ordering is used to
determine which parts of the image should be rendered on top. This is best explained
by example.
In a locked-off camera shot where a car is moving through the frame, the background does not
move, so it produces small, or slow, vectors. The car produces larger, or faster, vectors.
The Depth Ordering in this case is Fastest on Top, since the car draws over the background.
In a shot where the camera pans to follow the car, the background has faster vectors, and the
car has slower vectors, so the Depth ordering method would be Slowest on Top.
Clamp Edges
This checkbox is displayed only when Interpolation is set to Flow. Under certain circumstances,
this option can remove the transparent gaps that may appear on the edges of interpolated
frames. Clamp Edges can cause a stretching artifact near the edges of the frame that is
especially visible with objects moving through it or when the camera is moving.
Because of these artifacts, it is a good idea to use clamp edges only to correct small gaps
around the edges of an interpolated frame.
Chapter – 100 Miscellaneous Nodes 2234