Additional controls appear in the Shape Inspector’s Style pane when the Brush Source is a multi-frame object such as a QuickTime movie or image sequence:
Play Frames: A checkbox that controls playback of Brush Source movie or image sequence. If the checkbox is selected, playback of the clip loops; if the checkbox is deselected, the paint dabs use the still frame specified by the Random Start Frame parameter or the Source Start Frame parameter (described below).
Random Start Frame: A checkbox that introduces variation to image brush strokes when the Brush Source parameter contains a multiframe movie or image sequence. If the checkbox is selected, each dab uses a different random frame in the source clip. If the Play Frames checkbox is selected, dabs begin animating from this random frame. If the Play Frames checkbox is deselected, dabs do not animate, but display the random frame as a still frame. You can adjust this pattern of randomness using the Random Seed button in the Stroke pane.
Source Start Frame: A mini-curve editor (available when Random Start Frame is deselected) that defines the frame where playback of the source clip begins in the paint dabs. (See Work in the mini-curve editor.) The Source Start Frame default keyframe value is 0. You can change the start frame for all dabs, or you can create a curve so start frames vary over the length of the stroke (different dabs use different start frames). For example, if the first Source Start Frame value is 50, each dab begins playback at frame 50. If you create an animation curve that begins at 50 and ends at 250, each dab begins clip playback at a progressively later frame.
Note: The Play Frames checkbox must be selected for playback to occur. If Play Frames is deselected, you can display different still frames over the length of the stroke.
Click the Source Start Frame disclosure triangle to see the Stroke Length and Source Start Frame controls:
Source Start Frame Over Stoke: A slider that adjusts the value of the selected keyframe in the mini-curve editor.
Stroke Length: A slider that adjusts the value of the selected keyframe. Stroke Length is mapped horizontally on the mini-curve editor graph and provides a visual representation of the position of the changes in start frame value (keyframes) over the length of the stroke.
Hold Frames: A slider that sets the number of times each frame of the source movie is repeated during playback. The larger the Hold Frames value, the slower your playback.
Hold Frames Randomness: A slider that varies the number of frames to “hold.”