[dreaming out loud] Rockbox as a DJ turntable?

[bubuz0]

Hello there,

I found trace some years ago of starting a discussion about using rockbox as a rudimentary DJ setup (mixer + 2 audio streams) https://forums.rockbox.org/index.php?topic=11638.0

I really love the idea, but thinking on what could be more approachable given hard+software limitations, left me wondering:

-> how to tune rockbox in such a faction that one device could be used a one DJ turntable, meant to be used side by side with another device/turntable, both connected to a mixer? This could provide for cool on-the-go DJ sets and other entertaining "ping-pong" and sessions...  Ideally with an active mixer and it's own cross-fader, EQ controls, etc. but one could also consider using a very basic passive mixer, so each "turntable could manage one part of the makeshift "mix" with proper use of volume control, and potentially automated fade-outs and fade-ins..?

What would be the requirements for that to happen? Would it be in the form of a plugin, or a clever hack of some WPS screen/theme? or something else? I don't know the technical insides of rockbox enough (at all!) to answer this.

Ideally, one "turntable" would have:
- fine-tune seek in track with wheel control (possibly quickly shiftable to fine-tune pitch control with the wheel?) and play/pause
- pitch control being readily accessible in fine-tuned and bigger increments, possibly with vol +/- or << / >> buttons?
- some clever shortcuts to make the remaining buttons used to either: fade-in / fade-out / next track / previous track / all sorts of mute / hi/lo-cuts / etc. the possibilities are endless

What do you think? Is it science-fiction? Would it hurt some hard limits (the fine-tune seeking in flac maybe?)?