v0.6.0 — AVIF output, preview before converting

Skidbladnir 0.6.0 adds a second output format and the preview the app has long promised. WebP output is still byte-for-byte identical to cwebp 1.6.0; that was re-checked for this release across 76 settings.

What's new

• AVIF output. A new Format selector switches between WebP and AVIF. The AVIF panel offers quality, alpha quality, speed, 8- or 10-bit, YCbCr or RGB, what happens to colour under transparency, and multi-threading. WebP and AVIF each keep their own settings while you try the other, and resize applies to both. AVIF files are checked by decoding them with libavif's own avifdec, which confirms the size, the colours and the transparency.
• Preview before converting. Pick one of your selected files and see it encoded with the current settings beside the original, with the size and the saving. Nothing is written to disk until you convert. The panel also tells you when you've changed settings since the last preview.
• An Intel Mac build. There is now an x64.dmg next to the Apple Silicon one.
• The Windows installer is now tested. Every change installs it silently and exercises the installed app in CI. Before this release, nobody had ever run the Windows build.

Downloads

• Linux: .deb and .AppImage
• Windows: x64-setup.exe
• macOS: aarch64.dmg (Apple Silicon) and x64.dmg (Intel)

Known gaps

• Both macOS builds are untested. They have never been launched.
• AVIF preview on some Linux systems. Showing it needs a web engine that can display AVIF. Ubuntu 24.04's cannot, and the AppImage bundles it, so there the preview shows a notice instead of the image. The AVIF files themselves are unaffected.
• AVIF limits. It can't be read as input yet. It is always written 4:4:4. A file that's mid-encode can't be cancelled; it finishes and is then discarded rather than written.
• Nothing is code-signed, and there is no auto-updater.

This is a prerelease: the migration from the Electron app is not finished.