SlitScan node
This documentation is for version 1.0 of SlitScan (net.sf.openfx.SlitScan).
Description
Apply per-pixel retiming: the time is computed for each pixel from the retime function, which can be either a horizontal ramp, a vertical ramp, or a retime map.
The default retime function corresponds to a horizontal slit: it is a vertical ramp, which is a linear function of y, which is 0 at the center of the bottom image line, and 1 at the center of the top image line. Optionally, a vertical slit may be used (0 at the center of the leftmost image column, 1 at the center of the rightmost image column), or the optional single-channel “Retime Map” input may also be used.
This plugin requires to render many frames on input, which may require a lot of memory.
Note that the results may be on higher quality if the video is slowed fown (e.g. using slowmoVideo)
The parameters are:
retime function (default = horizontal slit)
offset for the retime function (default = 0)
gain for the retime function (default = -10)
absolute, a boolean indicating that the time map gives absolute frames rather than relative frames
frame range, only used if the retime function is given by a retime map, because the actual frame range cannot be guessed without inspecting the retime map content (default = -10..0). If “absolute” is checked, this frame range is absolute, else it is relative to the current frame
filter to handle time offsets that “fall between” frames. They can be mapped to the nearest frame, or interpolated between the nearest frames (corresponding to a shutter of 1 frame).
References:
An Informal Catalogue of Slit-Scan Video Artworks and Research, Golan Levin, http://www.flong.com/texts/lists/slit_scan/
Inputs
Input |
Description |
Optional |
---|---|---|
Source |
No |
|
Retime Map |
Yes |
Controls
Parameter / script name |
Type |
Default |
Function |
---|---|---|---|
Retime Function / |
Choice |
Horizontal Slit |
The function that gives, for each pixel in the image, its time. The default retime function corresponds to a horizontal slit: it is a vertical ramp (a linear function of y) which is 0 at the center of the bottom image line, and 1 at the center of the top image line. Optionally, a vertical slit may be used (0 at the center of the leftmost image column, 1 at the center of the rightmost image column), or the optional single-channel “Retime Map” input may also be used.
Horizontal Slit (horizontalslit): A vertical ramp (a linear function of y) which is 0 at the center of the bottom image line, and 1 at the center of the top image line.
Vertical Slit (verticalslit): A horizontal ramp (alinear function of x) which is 0 at the center of the leftmost image line, and 1 at the center of the rightmost image line.
Retime Map (retimemap): The single-channel image from the “Retime Map” input (zero if not connected).
|
Retime Offset / |
Double |
0 |
Offset to the retime map. |
Retime Gain / |
Double |
-10 |
Gain applied to the retime map (after offset). With the horizontal or vertical slits, to get one line or column per frame you should use respectively (height-1) or (width-1). |
Absolute / |
Boolean |
Off |
If checked, the retime map contains absolute time, if not it is relative to the current frame. |
Max. Frame Range / |
Integer |
min: -10 max: 0 |
Maximum input frame range to fetch images from (may be relative or absolute, depending on the “absolute” parameter). Only used if the Retime Map is used and connected. |
Filter / |
Choice |
Nearest |
How input images are combined to compute the output image.
Nearest (nearest): Pick input image with nearest integer time.
Linear (linear): Blend the two nearest images with linear interpolation.
|