mixxx VS moodbar

Mixxx is excellent and has pretty wide hardware support.

FYI the "limited" functionality of Rekordbox can be hardware unlocked with some Pioneer controllers.

https://mixxx.org/

There are quite a few DJs that use Ableton for DJing (or hybrid sets). Of course, Ableton wasn't made with DJing as its main function in mind but you totally can use it for that purpose and (with some tweaking) do everything and more that would be possible in a dedicated DJing software (like Traktor or Rekordbox or Mixxx)

I’ve used Mixxx a little bit and have been surprised how capable it is. It’s an open source project and is free to download: https://mixxx.org/

Mixxx (this one's free)

Mixxx

Related works: https://github.com/mixxxdj/mixxx/pull/4027

Mixxx (you already mentioned this; it's certainly a great piece of free software to test the DJ waters with and works with a lot of gear).

Alternatively, you can also use Mixxx with the S4 MK2. Mixxx is free. But instead of a Traktor control vinyl record, you'd use Serato timecode instead, as stated in the docs.

If the device is class-compliant, i.e. it follows the generic USB spec and doesn’t need drivers installed, it can work under Linux. However the free software you get with the controller (Serato, Rekordbox, Traktor etc.) won’t. The alternative is to use Mixxx. It’s free and open source. You can check their controller support. https://mixxx.org/

If you don't like any of those, aren't you glad you didn't spend the money to find out the hard way? There's more DJ software than those two, so try out these as well: Traktor Pro 3, Virtual DJ, DJUCED, or Mixxx.

I loved Amarok for years, including after the 2.0 rewrite. It was my favorite as long as the main way I listened to music was a collection of local files, despite flirtations with other cool projects like MPD, Subsonic, Ampache, etc.

Documentation from the Exaile project (another music player inspired by Amarok!) indicates that while the Amarok developers did not invent the moodbar, their implementation is the one we know and love (which was packaged as the standalone `moodbar` CLI program that could be used to generate moodbars that other players would also read):

https://github.com/exaile/moodbar

For me, Amarok was so good that it gave 13-year-old me enough reason to switch operating systems for daily use.