[linux-audio-user] Re: Linux Lighting

Olivier Guilyardi ml at xung.org
Wed Nov 30 12:56:33 EST 2005

Dirk Jagdmann wrote:
>> Say I plan lighting for a specific club : is it like each lamp,
>> effect, motor
>> will be assigned a to given channel ? I'd then ask the club's
>> technician : "what
>> channel is this lamp assigned to ?" (or he'd give me specification)
> Yes, for simple lamps it's one channel (thus one byte).
> [...] As long as you don't want to spent hundereds of hours
> coding (which will be difficult unless you've got each of those moving
> light for testing available) you have little chance to get anywhere [...]

Okay I'll focus on lamps.

> However moving lights are generelly better controlled live from a
> dedicated console. So if you are playing in a well equipped club you
> could drive normals lamps with your own software and special effects
> with the local lighting console. Then it's just a matter of merging the
> two DMX streams if the club has all equipment on the same DMX universes.
> This merging could either be accomplished with a small external box, an
> DMX input interface for your laptop or perhaps via the lighting console.

That's an important point. But if I understand correctly, I need to know how to
"merge" or "route" DMX streams, either at software or hardware level. Needs some

>> All of this sounds great. But how stable is dmx4linux ? Already used
>> it on real
>> live shows ? (I'm not talking about big/huge shows)
> Yes we've used it here: (horrible german website)
> http://forum-schenefeld.de/

Nice concert hall.

Okay... I've just had an idea for a new project :


* Name : Jacklight
* Purpose : act as a bridge between Jack audio streams and DMX lighting
* Basic features :
    1 - set the brightness of a lamp according to the level of a given audio

    2 - a single stream can be connected to several DMX channels (= several
        lamps), and several streams can be connected to a single DMX channel.
    3 - each DMX channel is assigned a level control, to customize the
        audio-to-brightness conversion ratio
* Advanced features :
    4 - GUI : a gtk based interface that allows to easily add/remove DMX
        channels. Additionally, it could try and represents lamps on the screen,
        with some (customizable) color squares
    5 - Midi : each channel level control could be assigned to a Midi
        Continuous Controller. For Live operation, that would allow to use a
        hardware controller, and turn a knob to decrease/increase every
        channels' audio-to-brightness ratio,

* Mode of operation :
Basically, you choose a set of DMX channels. Each of these are then assigned a
given JACK input port. Thanks JACK, this design allows much freedom in audio
streams to DMX channels bindings (one to one, many to one, one to many, many to
many). Then it's a just a matter of reading the audio level on a Jack port and
setting the corresponding DMX channel value accordingly, taking the
audio-to-brightness conversion ratio into account.


Actually what I basically want is to assign a DMX channel to every Jackbeat
track (see http://samalyse.com/jackbeat), and set the brightness according to
the audio level. But coding a separate application as Jacklight would let
Jackbeat continue to do its simple job (= not getting bloated), and allow for
much more flexibility.

With a few tracks, this could produce very interesting light effects, that are
closely related to the music being played.

What do you think of this idea ? Does a such tool already exist ?


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