Creating level meters in Quartz Composer, part 2
This tutorial assumes that you have completed all the steps in part 1, or that you begin with the SimpleLevelMeter.qtz file.
So far we have created a single LED style level meter which reacts to the audio input on your Mac. The next part of this tutorial gets a bit complex. We need to get input from the spectrum of audio frequencies, and create a number of duplicate Meter patches to interpret that data.
Creating level meters in Quartz Composer
Previously I wrote about Quartz Composer and the creation of LatheMachine, a visualizer module included in AudioCodex. In that case, I did what a lot of people do when learning Quartz Composer. I found a qtz file which was interesting or in some way relevant to my goal, opened it up and tweaked it to my liking.
One great thing about Quartz Compositions is that there is no way to compile the file into an opaque, uneditable format. All qtz files are open source. This means that you can learn from examining other people's compositions, or by building a new composition based on someone else's graph.
The long run, continued...
MachineCodex is not a large company. We love Cocoa, and we love our little media player. We don't see it as a threat to anyone, it is just a tool that we ourselves have a use for. We'd love to sell a million copies of course, but if we don't - well, we sure had fun and learned a lot along the way.
By the middle of 2007, we were feeling quite good about MachineHead and our growing user base. We were gradually eliminating bugs and our users had begun sending in encouraging and useful feedback.
MachineHead 0.61b main window
We were feeling so good, we went from version 0.6b to version 0.8b in two months! We were powering along, and 1.0 seemed to be just around the corner.
The long run
After more than 2 years of development, AudioCodex 1.0 has been released. Obviously, this is a landmark for us. Now our little audio player is launched into the world, to fly or fall on it's own merits, without the safety net of a "Beta" after its name. What happens next is, for us, the interesting bit. With this in mind, it might be time to take a short trip back into the past to see how far AudioCodex has come. Set the TimeMachine for 2005...
MachineHead 0.09b interface
LatheMachine
Like everyone else in the world, I have been mucking about with Leopard on my Mac. As a developer, Leopard holds a lot of attraction for me. I can see myself spending an almost infinite amount of joyful time just coming to grips with all the new stuff Apple have bundled into Cocoa.
One thing I've been particularly looking forward to is the new Quartz Composer 3.0. AudioCodex is a host for Quartz Compositions, so new QC features add significant functionality to our app for free. Of course, there's always the worry that new stuff will break our implementation, but thankfully that hasn't happened.
One of the things that interests me most is the new Music Visualizer protocol included in Leopard QC, which defines some properties that can be plugged into data piped in from an application.
Dr StrangeCodex: Or How I learned to stop worrying and love criticism
It's amazing how much work goes into software development. I'm not sure that anyone who hasn't been involved in developing an app can really appreciate the sheer level of sustained intellectual and emotional effort necessary.
Mise en scéne
I began learning Cocoa about 4 years ago. At the time it seemed like it might be a nice hobby to take up. I had been inspired by Wil Shipley and the buzz created by CocoaDev, CocoaRadio and other blogs. I had gathered that Cocoa development was relatively easy; at least it was billed as a manageable learning curve, and Objective-C code did indeed seem much more palatable than that nasty C++. All this was underpinned by the siren call of the NeXT-ish dream of user-created software.
Whither AudioCodex
In the face of the majesty and power of iTunes, one might ask the question ‘whither AudioCodex?’, and it’s a fair cop... why complicate my life with a new audio playback app when iTunes does almost everything I want it to do?
Let me start out by saying it up front; AudioCodex ( or the ‘Codex) is NOT intended to either replace or displace iTunes. Like almost all Mac users, there are certain things I use iTunes almost exclusively for, like importing CD’s as MP3‘s &/or m4a’s, organising playlists, and working with iPods, and of course the gem in the crown, the iTunes store, which is of course Apples’ exclusive domain, a place where MachineHead would never be allowed to tread even if I wanted it to.
Zen of AudioCodex
Stevie Ray Vaughan’s ‘Scuttle Buttlin’ is a song I’ve been trying to master for years. It’s about a million notes squeezed into one minute twenty seven seconds of blues mastery. That one song contains half a dozen of the coolest riff’s ever created in all of history, and I would dearly love to be able to play it true, but she is a tough mistress. Not only is there a constant cascade of notes to deal with, all packed as tight as sardines in a can, there’s also the fact that Stevie Ray almost always played with his guitar tuned one semi-tone below concert tuning, to allow him to use heavy gauge strings with lower tension and keep the skin on his fingers intact for an extra half-hour per show.