Recent exploits w/ Linux as Midi Filter / Processor / Router

[sonic]

Hi folks! Recently I have been having fun shuffling my (mostly hardware) midi setup around, and in the process learning a bunch of new stuff, much of it concerning, and via Linux. So I thought I would write a wee post.

One thing I found myself lacking has been a hardware midi merger so I can merge the outputs of various keyboards, controllers, and an electronic drum kit. Along with a Midisport 4x4 midi/usb interface Linux has come to the rescue. The ALSA library is excellent and has some great utilities like amidi and aconnect.

Using amidi I have been able (with the assistance of JovianPyx - thanks Scott!) to deconstruct the sysex on a Boss SE-50 Effects box in order to control it's parameters via Cubase on the Atari ST and in turn via a modern midi control surface.

aconnect lets me merge midi data streams from the incoming ports of the Midisport. Unfortunately it appears not to cope well with midi active sensing messages from my Roland TD-3 drum brain. I can't disable them on the unit, so I am aiming to filter them out via the linux box. Initially I tried using a command line sequencer/filter utility called Midish. I was convinced it would do the job, but it appears that it passes all sysex level data unfiltered to all ports by default, even with a filter rule to block 'everything'! A shame, as it seems like a nifty little piece of software.

I could contact the developer of midish, but instead I am moving onto a Python library called Mididings. Mididings is a fair bit more flexible and open-ended - rather more of a platform than an application. It is proving to be a slightly steeper learning curve, as I've never used Python before and the Mididings documentation is minimal. Still, it's not too complex a script I need to write, so hopefully it won't take too long.

Anyhoo I thought I'd post something on here to document my exploits, and see if any others are doing (or interested in doing) anything similar. I'm not sure if this forum is strictly the right place for it, as this is rather Linux as a kind of router/server rather than a workstation.

Once I have got things working I may attempt to move the setup to a Raspberry Pi which I leave running quietly, SSHing in as necessary.

[agerven]

Hi Sonic, and all other interested parties,

I stumbled across your message by accident and I'm glad I did. Interesting to see any other people working with the Linux ALSA library.

Myself I'm currently working with a Raspberry Pi hardware platform running Linux and the ALSA library. I'm developing an application from scratch that provides a midi monitor with a subset of MidiOx features, with the intention to build an application that allows MIDI system exclusive dumps from synthesizers to a (any) USB memory stick / drive and vice versa. It is in an advanced state, currently working on manufacturer / model specific plugins. A plugin for the Roland D50 is my first priority. Plugins for Oberheim Matrix 6(R)/1000 and Waldorf Microwave 1 are next on the roadmap.

I have never heard of midish or mididings, and am building my application in python from scratch, but I'll sure look into those alternatives. Thanks for mentioning them.

Hopefully there are more of you who have experience with or are developing it using the Linux ALSA library. Any response, or a new group of interest, are welcome.