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[Bug]: DemoRunner Pitch Shift and Timing chipmunk effect

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
15/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
cpp
Domain
audio-video-rtc

Research direction

The demo is the 'Pitch and Time' page of the DemoRunner example app; start there and see which engine classes it drives for pitch shifting and time stretching. Check whether the tempo slider is wired to the Edit's tempo or the time-stretcher ratio, and whether pitch is passed as semitones or a playback-rate ratio — the 'chipmunk' result hints at a rate change rather than a true pitch shift. Done would be a reproducible answer on whether this is demo wiring, an engine limitation, or expected behaviour of the algorithm, then a fix or documented limitation. Note the report is 580 days old with two comments and no decision.

Written by the indexing model from the issue text.

Description

Detailed steps on how to reproduce the bug

On macOS I was testing the DemoRunner Pitch Shift and Timing demo. I loaded an audio clip that had vocals and music. When Adjusting the pitch I notice that vocals sound like chipmunks. I selected both algorithms but both had the same effect. I did not adjust the pitch by much. Also I noticed that with the timing when I adjusted the slider it will pause the audio clip for a brief moment and start back playing. Is there a way to speed up audio without the momentarily Pause? Also I noticed that while I did adjust the speed/tempo slider the tempo did not speed up or slow down.

reproduce: run the DemoRunner and select Load Demo, select Pitch and Time. load a audio file and try to adjust the sliders

What is the expected behaviour?

I was expecting to slide the pitch slider and the pitch adjust higher or lower without chipmunk effect.
I was expecting to slide the time(tempo.speed) slider and the audio speed up or slow down. Also was expecting it to do this without the audio stopping when making timing adjustment

Unit test to reproduce the error?
I am using the code from the example for pitch and time in the DemoRunner
Operating systems

macOS

What versions of the operating systems?

I am on the latest version of macOS 2025

Architectures

ARM

Stacktrace
Plug-in formats (if applicable)

No response

Plug-in host applications (DAWs) (if applicable)

No response

Testing on the develop branch

The bug is present on the develop branch

Code of Conduct
  • I agree to follow the Code of Conduct
Dominant language
C++
Stars
1.5k
Forks
222
Avg merge
15h 44m
Merged PRs (30d)
33

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