Shelf Filter added

[SteveDaulton]

Resolves: Absence of a shelf filter in Audacity

Audacity has High-pass, Low-pass, and a Notch filter, but notable by its absence there is no shelf filter. This pull requests adds the missing filter. The filter can be set for High-shelf or Low-shelf.

• [ x] I signed CLA
• [ x] The title of the pull request describes an issue it addresses
• [ x] If changes are extensive, then there is a sequence of easily reviewable commits
• [ x] Each commit's message describes its purpose and effects
• [ x] There are no behavior changes unnecessary for the stated purpose of the PR

Recommended:

• [ x] Each commit compiles and runs on my machine without known undesirable changes of behavior

[petersampsonaudacity]

Testing on W10 with @SteveDaulton 's branch build: audacity-win-3.3.0-alpha-20230223+9066b72-x64

The Shelf Filter appears in the Effects menu - BUT it appears in the below the line section and not in the EQ and Filters section of the Effect menu (which is where the High Pass and Low Pass filters properly reside):

[SteveDaulton]

BUT it appears in the below the line section and not in the EQ and Filters

In your EffectsMenuDefaults.xml file, you need to add <Effect>Shelf Filter</Effect> to whichever <Group> you want the effect to appear in.

When I built from source, the EffectsMenuDefaults.xml file was NOT copied into the build folder, so I'm guessing that menu sorting is a work in progress, probably with a view to making it user configurable. The EffectsMenuDefaults.xml file was recently moved from presets/EQDefaultCurves.xml to resources/EQDefaultCurves.xml, which may be why it wasn't copied using the build steps given in BUILDING.md, but I'm only guessing what the development team are intending.

I agree that the EQ and Filters group would be a logical place to put this effect in the default grouping.

[SteveDaulton]

which may be why it wasn't copied using the build steps given in BUILDING.md,

I've asked Dmitry about this. He said: "I think it is only copied on install"

I've not set a default menu group - as it says in the pull request template: There are no behavior changes unnecessary for the stated purpose of the PR.

[Paul-Licameli]

Is this line correct?

[SteveDaulton]

I'm not sure which line you are referring to, but lines 5 to 8 look fine.

The "release" version number refers to the plugin, not to the version of Audacity. It doesn't really matter what number is used so long as each subsequent update is higher than the previous. All of my plugins use the earliest Audacity version that I tested the plugin with as the initial "release" number, and then increments from that point. (I wrote Shelf Filter to be compatible with Audacity 2.4.0 and later). If there's any change to the plugin, the "release" number should be bumped.

[Paul-Licameli]

I meant line 8 and this satisfies me.

[dozzzzer]

Tested on Windows and macOS

[petersampsonaudacity]

I have pre-prepared the documentation for this - including the zebra-table on the EGATs page in the Manual.

Once this gets pulled all I need to do is switch to the new Zebra-table