New in 2.3: KeyFinder support
Starting with the 2.3, Mixxx will integrate support for the excellent KeyFinder library by Ibrahim Sha'ath.
KeyFinder is a pretty accurate open-source key detection tool. It's been in the top 3 of the 2020 key detection comparison on Reddit and performs considerably better than the key analyzer from the QM-DSP library that current stable version of Mixxx is using.
Unfortunately, it's also a lot slower than the QM-DSP algorithm (because the latter divides the sample rate by 8 and only analyzes every 8th window, resulting in a speedup factor of 64). We hope to improve performance in the future. Until then, the Queen Mary key Analyzer will be selected by default and you'll have to enable KeyFinder in the Key Detection settings.
On Windows, macOS, Fedora and Arch Linux, KeyFinder support is already enabled. To try it out, grab one of the 2.3 beta builds from our download page. On Ubuntu, KeyFinder is not enabled yet, because we didn't find the time to create a DEB package for it.
If you want to help with out with that or work on improving key detection in Mixxx, get in touch with us on Zulip Chat.