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IDProjectCategoryView StatusLast Update
0007859ardourfeaturespublic2020-01-13 01:46
Reporterdhealey Assigned To 
Status newResolutionopen 
PlatformSome Other LinuxOSSome Other LinuxOS Versionunknown
Product Version5.12 
Summary0007859: Pitch shift that works in real-time
DescriptionThe built in pitch shifting technique currently works by rendering a new file with pitch shifting applied. There are a few issues with this approach.

You don't always know exactly how many cents you need to shift a sound. So you have to open up the pitch shift interface, try a value, wait for it to render. If it's correct then great, if it's not then you have to do it again until you hit the right value. This can take a while, especially when there are many files to be shifted by different amounts.

In an effort to be non-destructive the pitch shifter creates a new file and keeps the original. This is fine for a small amount of audio but when dealing with large sessions this can add up to extra gigabytes of data. You may say that once you've found the correct pitch shift value you can then just delete the original so you don't use extra space but of course this then makes it a destructive process.

The alternative solution to this issue is to use a third-party pitch shifting plugin. I've tried all of the free ones and the only one that produces minimal artefacts is the rubberband lv2 plugin. Since Ardour uses Rubberband anyway why not just have the functionality built in? It could be accessed as an envelope like volume or panning are.

Now why can't I just use the Rubberband plugin, you ask... Most of the time it's great, but sometimes at the start of regions it clicks or pops and this comes out in the rendered file too and I've found no-way to prevent this, and all solutions offered in the IRC couldn't help.
TagsNo tags attached.



2020-01-13 01:46

reporter   ~0020915

Good news! I tinkered with the Rubberband ladspa plugin source code (increased the buffer size) and it's now much more usable. It would still be nice to have non-destructive pitch shifting built in to Ardour though.

Issue History

Date Modified Username Field Change
2019-12-05 00:24 dhealey New Issue
2020-01-13 01:46 dhealey Note Added: 0020915