Sunday, October 21, 2012

HTML5 Spectrum Analyzer: In 3d

I've created a new 3d version of my HTML5 audio spectrum analyzer using Three.js.

Check it out here

Where it used a d3 bar chart before, the frequency amplitude is now represented in changing the size of some classy wood-paneled 3d cubes.

You can use mouse and scroll over the scene itself to orbit the camera around the cubes.

Like the older version, the default audio is some music I made but you can enter any URL or use live input in Chrome Canary.  All of the other slider controls are the same too.

3d version on Github

Thursday, October 4, 2012

HTML5 Spectrum Analyzer: Live Audio Input

This week, I've added live audio input to the HTML5 spectrum analyzer.

Click the button that says Use audio input and then click Allow when prompted to give your browser access to your computer's audio input.  You can then click Use audio file to switch back to the audio file.

I've also added an intensity control that allows you to juice up the visual intensity without sacrificing volume or accuracy.

Of course, it may not work in your browser:

Is it ever that simple?  At time of writing HTML5 live audio input is only supported in Chrome Canary.  You need to go to about:flags in the URL bar, and then enable Web Audio Input near the bottom of the list

Spectrum Analyzer on github

Monday, October 1, 2012

Quick Project: D3 / HTML5 Web Audio Spectrum Analyzer

For fun this last week I made a spectrum analyzer using D3 and the HTML5 Web Audio API.  Been meaning to check those out for a while, and spectrum analyzer seemed like the natural way to kill two birds.

Here it is running on Heroku with some of my music as the example track

And the github page here:

Increasing the curve setting gives the spectrum a more logarithmic display, traditionally more common for audio spectrum analyzers.

The other controls are pretty straightforward


Adding live audio input in Chrome Canary (10/4/2012)

Sunday, April 29, 2012

Quick Project #2: Ruby Methods for Protecting Against Timing Attacks

Breaking with my usual style, Quick Project #2 doesn't necessarily relate to music programming.

Today I came across a nice little article and demo on r/compsci about timing attacks.

Timing attacks are something that I had learned about a few years ago but for whatever reason had dropped from the forefront of my engineering consciousness. In order to bash myself over the head with it (and provide a universal solution), I created Ruby wrapper methods for Object#send and block evaluation that are padded with a fixed timing delay.

Here 'tis, including some basic String comparison examples at the bottom:

To use it, just pass in a "safe" duration (in seconds) that likely exceeds any possible amount of time it could take to evaluate the code. In the following example I use the greatly exaggerated value of .75 seconds. In the wild, you'll most likely be working in smaller durations

  is_match = ExpressionTimer.block(0.75) { "password attempt!" == "my password!" }

When the example is run, no matter how quickly the block actually evaluates, it will always take exactly 3/4s of a second to return. As a result, actual timing information is lost in the ether and can not be gleaned by any outside observer.

Wednesday, April 25, 2012

Quick Project #1: Extract Audio Samples From Online Video

As I get ready to move once again (this time to the Ridgewood/Bushwick border) there's not a whole lotta time for personal projects. Yesterday I decided that I would find a quick one and do it no matter how useless it was.

Turned out, I came up with something that's going to be pretty useful (for me). Last week, a coworker pointed me to marcel's awesome Ruby giftube script which extracts animated gifs from online videos. I've been looking to incorporate more audio samples in my music for quite some time, so I forked his script and changed it to extract audio samples instead of gifs, complete with mp3 conversion.

Here's the result:

Sunday, March 25, 2012

MicroOSC: a Ruby DSL for OSC

Being on my way to the west coast and out of arm's reach of the synths, I've had a few hours to switch gears and put together a quick Ruby gem, MicroOSC. It's a utility and DSL for dealing with OSC messaging.

gem install micro-osc

I applied the same principle to OSC that I applied to MIDI with MicroMIDI: distilling the simplest messenger interface that I could think of.

Unlike MIDI, OSC deals with generic user-defined messages. This eliminates the need for describing different concrete message types, something that added a lot complexity to MicroMIDI.

MicroOSC can function as a server, a client or both. In this example, I'll demonstrate them separately, having the two programs talk to each other over a local network.

Here is a server:

require "osc"

OSC.using(:input_port => 8000) do

  receive("/greeting") { |val| p "received #{val}" }

  p "Ready to receive OSC messages on port(s) #{input_ports.join(', ')}..."



Once you have this running, you should see "Ready to receive OSC messages..." in your Ruby console. Switch to another window and run this client program:

require "osc"

o = OSC.using(:output => { :host => "localhost", :port => 8000 })
o.out("/greeting", "hullo!")

After running it, flip back to your server program and see “received hullo!”, confirming that your two programs were in fact talking to each other!

Notice that in the second program I didn't use a Ruby block style. Doing it this way would generally be better for live coding, and probably some other scenarios as well.

That's it!

Look for another post with real-world examples, advanced techniques and combining with MicroMIDI soon.

Friday, February 24, 2012


It's break time for my programming projects while I actually play and record some music.  I also started a new job with Paperless Post that I'm dedicating a lot of my programming energies to.

I'll post here soon when I have anything of note to show for what I'm doing.

Here's a video of me on some hardware synths that a friend posted last year. It sounds somewhat similar to what I'm doing now.

I can never stay away too long; I'm sure I'll be back to grinding out some music tools once I have a few tracks done. Just not enough time for both at the moment...