DJ feature / UI for ROCKBOX - Discussion

[Hypnotic Monkey]

This thread is to discuss the ideas and technical details and try and find interested parties who would be willing to contribute to and see some kind of DJ functionality on rockbox capable DAPs, whether in a different build or a DJ mode as such.

This would allow an incredibly compact but powerful and conveniant way of DJing, especially with the mobile dj in mind.

I've already come up with some general ideas of what the interface could/would include, based around a 2 player 1 mixer setup, but again this is obviously by no means set in stone.


~ Core features such as pitch shift/bend

~ perhaps a basic bpm counter

~ ability to save set cue points and loops in a file such as songname.dj (which would be read when a song is played in "dj mode") either before or during a gig, and could also perhaps be programmed on a piece of external software on a pc for the sake of UI and then loaded onto the player.

~ hotstarts/loops (cue points/loops instantaneiously played on a single button press) could be achieved via some clever buffering.

~ easily accessible EQ (with kill switches?)

~ some players could perhaps handle some effects such as eq, low pass filters and echos.

~ ok getting really ambitious here, but some kind of scratching feature for players with touch pads (linear H10 type or click wheel) !!

I'll be the first one to admit im both lacking the programming skills and currently a working rockbox player, but I'll attempt to learn some of the former and fix the later as soon as possible, until then me and any other non programmer contributers can help in other ways such as the impending wiki page and of course giving ideas.

As i had expected, and has been confirmed this will likely require alot of work in the areas of utilising some clever buffering techniques, and so will perhaps require an entire rewrite of some of the core code of rockbox.

[rockerboxer]

This is a really good topic. The term 'iPod DJ' is just ridiculous with the original firmware. When I started discovering rockbox and found the pitch shift feature hiding in the context menu, I was quite pleased.

You mention some really good things, yes, one or the other is rather advanced. There is one major thing I missed in your post: mixing.
Having a mixer is rather important for djing. And most people just have one .
If my iPod Nano is capable of playing a 600kbps mpeg video and a 128kbps audio stream simultanously, aren't chances good it can play and mix two audio streams?

My programming skills a rather basic, so is my knowledge of  the hardware capabilities. Maybe someone how does know, can comment on this?
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This is my first post, so just let me say something important: I find rockbox amazing! Thanks for developing.

[Hypnotic Monkey]

thanks for you interest rockboxer. taking the mixer out of the equation would make the setup incredibly portable. Yes its true that its theoretically possible to mix 2 tracks on many examples of rockbox hardware, but that would only be the most desirable set up if it worked as well UI wise as a 2 player set up.   But then for less technical djs i suppose some simple crossfadin n a few effects would suffice...

the cpu load of pitch shifting two tracks, decoding them at the same time, possibly tracks with different and more cpu consuming formats (eg .ogg ) whacking on a eq on each track, a few effects, AND keeping the player as close to instantaneous in its response to input via a, presumably by now, very cluttered and slow interface. Im not sayin its impossible, just needs a lot of thought!

perhaps concentrating on the simple functions required as if the DAP was a deck would then allow future addition of a single player mixing capability?

just come back from holiday now, will try and start work on the wiki.

[Llorean]

Just as a note, the iPods have two CPUs so *in theory* you might be able to convince them to mix. We're only using one of them right now, so in theory you have twice the processing power available to you if you program it properly

Also, the Toshibas are ridiculously fast (relative to the other players).

[rockerboxer]

perhaps concentrating on the simple functions required as if the DAP was a deck would then allow future addition of a single player mixing capability?

Sounds good. I guess making a good and quickly responding interface on these small devices is hard enough. But extending the functionality one day to a 2-dex-in1-DAP-Setup should be kept in mind. I personally would use such a function for playing around with new tracks and trying out new sets, when I have spare time on the train or something, rather than buying a second iPod and using them for actual gigs.

Maybe you can keep this thread up to date on your work? I'd love to contribute to the progress.

[rockerboxer]

OK, it's been a while we've been talking about this. I haven't used rockbox for a while, and development has continued.. I'm still quite interested in seeing the dj functionality of rockbox improved.

So, let's imagine a minum scenario: the DAP is used as a single deck, for example just as a supplement to a pair of turntables/CDJs or whatever.

When going to the "pitch" menu, we have the following options at hand:
Pitch adjust - via scroll wheel (ipod etc.) or buttons
Pitch bend - temporary pitch change via buttons
(the other options, toggle semitone mode and reset pitch don't are not of interest here)

With these two things we already have the basic operations for beatmatching a track ready. What is missing is quick access to cueing the track. In order to restart the track from the beginning, or restart from reapeatA-B marker (abusing it as a cue point..) one would have to exit the menu and go back to the WPS. Which is not quite intuitive.

For a first try, we can set the A-marker in normal WPS. Then, in the "pitch" screen, we can hijack an unwanted button and let it change playback to the A-marker. Thus, we'd have pitch, pitch bend and jump-to-cue in one menu.

I'm just browsing through the code, hope I can do it..at least in a quick and dirty way.

[mrskittles]

I have a Sansa Fuze V2 and a retired Ipod Nano V2. I have always wished there was a demo/plugin that could scratch the music. I do realise that many players do not have the feature of a scroll wheel, but it would be fun to scratch using a wheel with compadible devices. I mean, rockboy does not have the most ideal button scheme to work with either, but i occationally use it and have alot of fun.

[Lear]

We're only using one of them right now, so in theory you have twice the processing power available to you if you program it properly

The MP3 decoder uses both cores though.

[torne]

It didn't in 2007, this thread has been necro'ed

[Lear]

Oops. I really should remember to look at the post date before replying.