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Old network
As of Houdini 20.5, use Copernicus nodes instead of Compositing nodes. Though both networks still exist, the Compositing network is now designated as COP Network - Old. The Compositing network and its nodes will be deprecated and then removed in a future Houdini release.
This operation uses a second input image to time warp the first input sequence on a per pixel basis. The second input image’s luminance is used to determine which frame to access in the first input. The 'Black Pixel Frame' and 'White Pixel Frame' are used to specify the frame range that the luminance values map to.
Tip
Try a Ramp or Noise COP as the second input.
Overloading VEX Parameters ¶
This operator is implemented in VEX, which supports parameter overloading. If the first input has a plane which matches an operation parameter’s channel name, the input plane will be used as the parameter’s value, effectively overriding it. The overloaded parameter is then evaluated from the plane on a per-pixel basis.
eg. If the input COP has the following planes:
C{r,g,b}
A
fogdensand it is fed into a VEX Fog COP, the fog density will be determined at each pixel by the fogdens plane, since the Fog Density parameter’s channel name matches the 'fogdens' channel name.
Scoping ¶
This operation may be restricted to certain planes, or components of planes. In addition, the operation may be applied to a subset of frames within the sequence. An image must have both its frame and plane scoped to be modified.
Images that are not modified are passed through, which does not take any memory or processing time.
Masking ¶
This operation may be masked, which restricts the operation to an area of the image. The mask may be inverted, brightened or dimmed.
The mask input is on the side of the node. The label on the connector indicates the plane being used as a mask.
The mask input can also be scaled to fit the output image’s resolution, if they differ. If this node is changing constantly, and the mask is not, it is somewhat faster to put a Scale COP down to do the resize for the mask image. Otherwise, the scale will occur every time this node cooks.
Parameters ¶
Time Machine ¶
Black Pixel Frame
The frame value that a black pixel represents.
White Pixel Frame
The frame value that a white pixel represents.
Pixels between the black and white will have frame values that are linearly interpolated between the Black Pixel Frame and the White Pixel Frame. Values above white or below black will be extrapolated.
Relative to Current Frame
If on, the frame value is added to the current frame, making the frame value an offset from the current frame. If off, the frame values represent actual frame numbers.
Blend Frames
If on, fractional frames are computed and pixels from the two nearest frames are linearly blended together to produce the output frame’s pixel.
Before Start
If a filtered frame is before the beginning of the sequence, this determines what frame to use.
Black
A black frame.
Cycle
Cycle back into the sequence from the end (so 2 frames before the start will use frame 'end-2').
Mirror
Mirror back into the sequence (so 2 frames before will use frame 'start+2').
Hold
Use the first frame.
After End
Similar to 'Before Start', except this parameter determines what frame to use if filtering goes past the last frame of the sequence.
Scoping ¶
This operation may be restricted to certain planes, or components of planes. In addition, the operation may be applied to a subset of frames within the sequence. An image must have both its frame and plane scoped to be modified.
Images that are not modified are passed through, which does not take any memory or processing time.
Masking ¶
This operation may be masked, which restricts the operation to an area of the image. The mask may be inverted, brightened or dimmed.
The mask input is on the side of the node. The label on the connector indicates the plane being used as a mask.
The mask input can also be scaled to fit the output image’s resolution, if they differ. If this node is changing constantly, and the mask is not, it is somewhat faster to put a Scale COP down to do the resize for the mask image. Otherwise, the scale will occur every time this node cooks.
Locals ¶
L
Sequence length
S
Start of sequence
E
End of sequence
IL
Input sequence length
SR
Sequence frame rate
NP
Number of planes in sequence
W,H
Width and height of image
I
Image index (0 at start frame)
IT
Image time (0 at start frame)
AI
Current plane array index
PI
Current plane index
PC
Num of channels in current plane
CXRES
Composite Project X resolution
CYRES
Composite Project Y resolution
CPIXA
Composite Project pixel aspect ratio
CDEPTH
Composite Project raster depth
CBP
Composite Project black point
CWP
Composite Project white point
| See also |
