Stretch CHOP
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Summary[edit]
The Stretch CHOP preserves the shape of channels and the sampling rate, but resamples the channels into a new interval. All data in the range is stretched or compressed to the new start and end positions.
A Reverse Interval parameter reverses the order of the samples of each channel.
Parameters - Stretch Page
Interpolation
interp - ⊞ - The interpolation method to use when resampling.
- No Interpolation
nointerp- Use the value of the nearest sample.
- Linear
linear- Use linear interpolation between samples when the interval is lengthened. Averages all samples near the new sample when the interval is shortened.
- Cubic
cubic- Cubically interpolates between samples, for smoother curves than Linear. This method is not recommended for channels with sharp changes.
- Pulse Preserve
edge- A linear interpolation that recognizes single sample pulses and preserves their height and one sample width. A pulse is a non-zero value preceded and followed by zero-value samples.
Constant Area
constarea - If enabled, keeps the area under the channel constant by scaling the values of the channel.
Unit Values
relative - ⊞ - Determines how Start/End parameters are interpreted:
- Absolute
abs- The value is the new start/end position.
- Relative to Start/End
rel- The value is a shift from the old start/end position.
- Relative to Current Frame
cur-
Start
start - The CHOP's new start position.
Start Unit
startunit -
End
end - The CHOP's new end position.
End Unit
endunit -
Length Scale
scale - Scales the length of the channel after determining the start/end interval. Good for doubling or halving the length.
Reverse Interval
reverse - Reverses the channel so that it plays backwards.
Parameters - Common Page
Time Slice
timeslice - Turning this on forces the channels to be "Time Sliced". A Time Slice is the time between the last cook frame and the current cook frame.
Scope
scope - To determine which channels get affected, some CHOPs use a Scope string on the Common page. See Pattern Matching.
Sample Rate Match
srselect - ⊞ - Handle cases where multiple input CHOPs' sample rates are different. When Resampling occurs, the curves are interpolated according to the Interpolation Method Option, or "Linear" if the Interpolate Options are not available.
- Resample At First Input's Rate
first- Use rate of first input to resample others.
- Resample At Maximum Rate
max- Resample to the highest sample rate.
- Resample At Minimum Rate
min- Resample to the lowest sample rate.
- Error If Rates Differ
err- Doesn't accept conflicting sample rates.
Export Method
exportmethod - ⊞ - This will determine how to connect the CHOP channel to the parameter. Refer to the Export article for more information.
- DAT Table by Index
datindex- Uses the docked DAT table and references the channel via the index of the channel in the CHOP.
- DAT Table by Name
datname- Uses the docked DAT table and references the channel via the name of the channel in the CHOP.
- Channel Name is Path:Parameter
autoname- The channel is the full destination of where to export to, such hasgeo1/transform1:tx.
Export Root
autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.
Export Table
exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).
Operator Inputs
- Input 0: -
- Input 1: -
Info CHOP Channels
Extra Information for the Stretch CHOP can be accessed via an Info CHOP.
Common CHOP Info Channels
- start - Start of the CHOP interval in samples.
- length - Number of samples in the CHOP.
- sample_rate - The samplerate of the channels in frames per second.
- num_channels - Number of channels in the CHOP.
- time_slice - 1 if CHOP is Time Slice enabled, 0 otherwise.
- export_sernum - A count of how often the export connections have been updated.
Common Operator Info Channels
- total_cooks - Number of times the operator has cooked since the process started.
- cook_time - Duration of the last cook in milliseconds.
- cook_frame - Frame number when this operator was last cooked relative to the component timeline.
- cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.
- cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.
- cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.
- cooked_this_frame - 1 if operator was cooked this frame.
- warnings - Number of warnings in this operator if any.
- errors - Number of errors in this operator if any.
TouchDesigner Build:
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