S_Feedback The previous frames of the input clip are transformed and combined with the current frame to give a variety of effects inspired by video feedback. The output of each processed frame is stored and then combined with the next frame. The feedback is reinitialized whenever any non-consecutive frame is processed: either the first frame, reprocessing a given frame, or jumping to another frame. You must process multiple frames of a clip in a row to observe the effect, and clearing your image cache before rendering may sometimes be necessary. In the Sapphire Time effects submenu. Inputs: Source:  The current layer.   The clip to be processed.

Parameters:

Prev Brightness:   Default: 0.8,  Range: 0 or greater.
For each frame, the previous output is scaled by this amount before it is combined with the new input frame. Normally this value should be less than 1.0 which causes previous frames to fade out over time. A value of 1.0 causes no fading, and values greater than 1.0 cause previous frames to become brighter over time.

Prev Color:   Default rgb: [1 1 1].
For each frame, the previous output is scaled by this color before it is combined with the new input frame. This is similar to Prev Brightness but affects the colors of the previous frames instead of just the brightness.

Prev Hue Shift:   Default: 0,  Range: -1 to 1.
Shifts the hue of the previous frames' colors, for each new frame.

Combine New:   Popup menu,  Default: Ave.
Selects the method for combining previous frames with the current frame.

Ave:  The current frame is averaged with the previous output, smearing moving objects out over time. The output is scaled by Fade and the input is scaled by 1.0-Fade for a weighted average, so Fade must be less than 1.0 for this to work properly. Unlike the other combine options, Ave should never affect the brightness of stationary objects in the clip.

Max:  The colors of the current frame and previous frames are combined with a maximum function. This makes the output frame at least as bright as the current frame, and will make brighter 'trails' for example if you have bright objects moving on a dark background.

Screen:  The colors of the current frame and previous frames are combined with a blend function. This can be used to accumulate the colors of a moving clip. However, non-black regions will become brighter with each frame.

Add:  The colors of the current frame and previous frames are added. This can also be used to accumulate the colors of a moving clip, with the non-black regions becoming brighter at each frame.

Over:  The current frame is composited over the previous frames using its Alpha channel. This uses pre-multiplied compositing, so where the alpha is black the Source image should normally also be black. If the input clip contains no Alpha channel, the luminance is used instead.

Under:  The current frame is composited under the previous frames.

New Color:   Default rgb: [1 1 1].
Scales the color of the current frame. Set this to the complement of Old Color to offset overly colored trails.

New Opacity:   Default: 1,  Range: 0 to 10.
Scales the opacity and brightness of the current frame.

Blur Amount:   Default: 0,  Range: 0 or greater.
The previous frames are blurred by this amount for each new frame. This has no effect unless it is positive.

Diffuse Amount:   Default: 0,  Range: 0 or greater.
The previous frames are passed through a pixel-diffusion process of this magnitude, for each new frame. This has no effect unless it is positive.

Amount Rel:   X & Y,   Default: [1 1],  Range: 0 or greater.
The relative amounts of horizontal and vertical blurring and/or diffusing. This has no effect unless Blur Amount or Diffuse Amount are positive.

Center:   X & Y,   Default: [360 243],  Range: any.
The center position for rotation and scaling, in screen coordinates relative to the center of the frame.

Z Dist:   Default: 0.95,  Range: 0.001 to 10.
For each new frame, the 'distance' of the previous frames is scaled by this amount. This causes zooming during the feedback process. Values greater than 1.0 zoom out and make the previous frames smaller, and values less then 1.0 zoom in and enlarge them.

Rotate:   Default: 3,  Range: any.
For each new frame, the amount of rotation in degrees to apply to the previous frames.

Shift:   X & Y,   Default: [0 0],  Range: any.
Shifts the previous frames by this amount for each new frame. If this is non-zero the Center location is less meaningful.

Wrap:   X & Y,  Popup menu,  Default: [No No].
Determines the method for accessing outside the borders of the source image.

No:  gives black beyond the borders.

Tile:  repeats a copy of the image.

Reflect:  repeats a mirrored copy. Edges are often less visible with this method.

Opacity:   Popup menu,  Default: Normal.
Determines the method used for dealing with opacity/transparency.

All Opaque:  Use this option to render slightly faster when the input image is fully opaque with no transparency (alpha=1).

Normal:  Process opacity normally.

As Premult:  Process as if the image is already in premultiplied form (colors have been scaled by opacity). This option also renders slightly faster than Normal mode, but the results will also be in premultiplied form, which is sometimes less correct.

Show Transform: Check-box, Default: off.
Turns on or off the screen user interface for adjusting the Z Dist and Rotate parameters.This parameter only appears on AE and Premiere, where on-screen widgets are supported.

Show Shift: Check-box, Default: off.
Turns on or off the screen user interface for adjusting the Opacity parameter.This parameter only appears on AE and Premiere, where on-screen widgets are supported.

See Also:

FeedbackBubble Trails TrailsDiffuse TimeAverage NearestColor

WarpRepeat WarpChroma Sapphire Plug-ins Introduction

© 2007, GenArts, Inc. All rights reserved.