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# Audio Timewarp

Audio Timewarp is a soft effect used to timestretch an audio segment. With Audio Timewarp you can change the speed and duration or the pitch of the audio. Audio Timewarp uses the DIRAC Time Stretching and Pitch Shifting Technology developed by DSP Dimension (www.dspdimension.com). Depending on the amount of timestretch applied, this soft effect may degrade the quality of the resulting audio.

When a clip with an Audio Timewarp soft effect has more than one audio track, the Edit Sync flag should be enabled on the selection. This will avoid phasing problems. Otherwise the effects will be rendered separately and out of sync.

NoteUnlike video timewarps, audio timewarps are limited to the speed range of 10% - 1000% and cannot be reversed. You also cannot mute an audio timewarp.

To apply the Audio Timewarp effect on an audio segment:

1. From the Record T/L, select the audio segment that you want to adjust.
2. From the Audio Soft-Effects menu, enable AudioTW.
3. Adjust the Audio Timewarp parameters.

   Use: | To:
   --- | ---
   Speed | Change the speed and duration of the audio clip based on a speed percentage. The values in the Time Ratio and Duration fields change automatically as you modify the speed percent.
   Time Ratio | Change the speed and duration of the audio clip by setting a time ratio. This is the ratio of the number of samples in the result divided by the original number of samples. The values in the Speed and Duration fields change automatically as you modify the Time Ratio.
   Duration | Change the speed and duration of the audio clip to create a destination clip with the required duration. The values in the Speed and Time Ratio fields change automatically as you modify the duration.
   Pitch Shift | Change the pitch of the audio clip. Leave this option set to1.00 X to keep the audio pitch constant when applying the timestretch. This is the ratio of the shifted frequency values divided by the original frequency values. (A Pitch shift value of 2 shifts one octave up; a Pitch shift value of 0.5 shifts one octave down.)
   Quality Factor | Select the quality of the resulting audio. This can be set to Quick, Standard, or High Quality mode. Use a lower quality mode to experiment with different settings, and then use High Quality to process the final result.
   Time/Frequency Localization | Select a time/frequency localization option that suits your audio material: Lambda1 - Ensures full time localization and is suitable for single-instrument tracks and voice-over. Lambda2 - Sets higher time localization and lower frequency localization. If applying Lambda1 results in an echo effect, this could be a better option. Lambda3 - Sets the time/frequency localization in mid ranges of time and frequency domains. This is the best general-purpose setting. Lambda4 - Sets higher frequency localization and lower time localization. Lambda5 - Ensures full frequency localization and is suitable for multi-instrument tracks, such as classical music.