[Alsaplayer-devel]DJ app

Mark Gibson mark@markg.co.uk
Sun, 10 Feb 2002 13:13:33 +0000 (GMT)

Its funny you should mention this Patrick. The whole reason
I got interested in jack and alsaplayer in first place is
because I was planning on putting together a GPL'ed DJ
mixing application.

Currently I'm browsing through the jack and alsaplayer
code to find the best way to do this.

Based on traditional DJ setup: 2 decks, 2 outs (PA+cue).
(forget the MIC - good DJ's don't use 'em :)
So far, I think the best bet is to create a separate
app that has a pair of stereo jack ports for connecting
two AlsaPlayers to (or any other jack app).
Apply gain/effects/x-fader and provide two stereo jack
outputs representing master and cue which can be connected
to any other jack inputs (eg. alsa_pcm:out_x).

I've still got some experimenting to do with jack.
But if anyone has some good ideas, let me know, or
if some one is already doing something like this
maybe we could work together.

Further on, I had some ideas about a generic GUI framework
where jack apps provided GUI components that fitted together,
eg. AlsaPlayer would provide components for playback control
(play/pause/speed etc.), the DJ desk provides faders/x-fader
etc, an alsa mixer provide sliders for soundcard levels
(master vol, front/rear vols).
Then these components can be logically patched together using
jack, and visually arranged in a window to suit the users
needs :)

- Mark.

On Sat, 9 Feb 2002, Patrick Shirkey wrote:

> Just revisiting the need I have for being able to switch
> between ports on the fly. ie to switch the signal from
> headphones to stereo output 1 or stereo output 2.
> I have asked on the jack list and the consensus there is
> that it will be better to have it available as a seperate
> gui for all jack aware apps to use. But I don't have the
> knowledge or time to do that now so I want to get it working
> in alsaplayer first.
> Any ideas on how I should accomplish this?
> I can easily code a menu box into the gui which allows
> the user to choose the output but how do I get this to
> actually work? Obviously it has to be instant and have
> no dropouts or noise. Possible a better idea would be to
> provide a fader and a switch. Then it would become a
> complete cj mixing app.