When exporting a .wv file, it adds its own metatag labels

[dozzzzer]

Describe the bug
When exporting a Wavepack audio file with some metadata, it adds some additional metatag fields to the file.

To Reproduce
Steps to reproduce the behavior:

1. Load an audio
2. Go to 'Export > Audio'
3. Select 'WavPack Files' in 'File Type'
4. Click Save
5. In Edit Metadata Tags dialog fill out the tags and click OK
6. Import this file in a new project
7. Go to 'Edit > Metadata' and check the metadata values

Actual behavior
The values filled out during export are added at the bottom of the table under the uppercase metadata tags:

Expected behavior
No new metadata tags added

Screenshots

2022-07-06_17-59-16.mp4

Additional information (please complete the following information):

• OS: [e.g. Mac High Sierra, Ubuntu 18.04, Windows 10]
• Version audacity-macOS-3.2.0-alpha-20220624+d82b516-universal

[LWinterberg]

I can't reproduce this anymore. It probably was fixed in #3330

[dbry]

When I first started testing WavPack I ran into the issue that by default Audacity will try the FFmpeg import before the WavPack one, unless "WavPack files" is selected in the open dialog. I created an Extended Import rule to fix this, but a user might not do that, and then they're going to get WavPack files imported by FFmpeg.

There are a few reasons that's not ideal, but one of them is that the Artist metadata field doesn't get imported, and I traced that to this code:

FFmpeg metadata handler

Because there's no case for WavPack (wv) it looks for "author" instead of "artist", and so that field goes missing.

I added a case for "wv" and fixed that, but maybe the best solution is to make sure that WavPack files are never imported by FFmpeg?