TimeScaleGUI

This is an initial version of the manual page describing proposed changes to the "Sliding Time Scale / Pitch Shift" effect.

Sliding Time Scale / Pitch Shift
This effect allows you to make a time varying change to the tempo and/or pitch of a selection by choosing initial and/or final change values. Tempo changes made without selecting a pitch change preserve the original pitch, and pitch changes made without selecting a tempo change preserve the original tempo. By changing only one of tempo and pitch and choosing the same initial and final value, you can use Sliding Time Scale / Pitch Shift in the same way as Change Tempo or Change Pitch to produce a high quality fixed change. However Sliding Time Scale / Pitch Shift lets you for example set the initial tempo change to -50% while also setting the final tempo change to +20%, the initial pitch change to +3 semitones and the final pitch change to +1 semitones. Because of the higher quality algorithm used, Sliding Time Scale / Pitch Shift is normally slower compared to performing the same effect with Change Tempo or Change Pitch. Time Tracks can be used to bend tempo more flexibly (also affecting pitch) using Envelope Tool.

Tempo (Rate) Change

 * Input Length (sec)
 * The length of the selection which will be effected. This can't be changed.


 * Output Length
 * The length of the effected output. You can change this to fix the output to a given length.


 * Initial
 * The percentage of the original rate, at the beginning of the slide (100% is unchanged, 50% is half speed, etc.).


 * Final
 * The percentage of the original rate, at the end of the slide

Pitch Shift

 * Initial (semitones)
 * The pitch shift in semitones (half steps) at the beginning of the slide


 * Initial (percentange)
 * The pitch shift as a percentage of the original frequency, at the beginning of the slide.


 * Final (semitones)
 * The pitch shift in semitones (half steps) at the end of the slide


 * Final (percentange)
 * The pitch shift as a percentage of the original frequency, at the end of the slide.

Options

 * Rate Slide
 * The type of slide which interpolates between the initial and final rate scaling.


 * Pitch Slide
 * The type of slide which interpolates between the initial and final pitch shift.


 * Slide Types
 * Linear Rate
 * Interpolate linearly between the initial and final rates (or pitch percentages).
 * Linear Stretch
 * Interpolate linearly the inverse rates, equivalent to the stretch factors (or the inverse pitch percentages).
 * Geometric
 * Interpolate geometrically (logarithmic). This is useful for pitch slides for producing portamento slides, which is linear in half steps.


 * Slide References
 * The interpolation can be with reference to the input or the output audio.
 * The resulting output length for reference=input can be considerably longer than with reference=output, when very low rates are used.
 * To simulate a "slowing record", try type=linear rate; reference=output.


 * Link Initial/Final
 * Fixes the initial and final rates, for a uniform change. This is for convenience in the UI, and doesn't affect the algorithm.


 * Link Rate/Pitch (Resample)
 * This forces all changes to the pitch to affect the rate and vice versa, so that the affect is performed by resampling.
 * The result in this case is produced faster, and sounds more "unprocessed" than for arbitrary settings.


 * Extreme Rates
 * Toggles more extreme settings for the rate slides.


 * Clamp Length
 * Setting this will force any subsequent changes to preserve the output length.
 * This is useful if you need to fit the output in a fixed output length, but don't know how you want to slide.