Category: ideas

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ep-341 Max/MSP – Spring 2015 week 14

(under construction)

Algorithmic composition and generative music – part 3

Sensors, sonification, and data.

Sensors

Data

Vine API in Max

A Max patch that displays, transforms, and responds to internet data.

building materials
  • Max (6.1.7 or newer)
  • Soundflower –

Both available from Cycling 74 http://cycling74.com/

The Max patch is based on a tutorial by dude837 called “Automatic Silly Video Generator”

download

The patch at the download link in the video is broken – but the javascript code for the Max js object is intact.

Download the entire patch from the Max-projects archive: https://github.com/tkzic/max-projects folder: maxvine

Internet API’s

API’s (application programming interfaces) provide methods for programs (other than web browsers) to access Internet data. Any app that access data from the web uses an API.

Here is a link to information about the Vine API: https://github.com/starlock/vino/wiki/API-Reference

For example, if you copy this URL into a web browser address bar, it will return a block of data in JSON format about the most popular videos on Vine: https://api.vineapp.com/timelines/popular

HTTP requests

An HTTP request transfers data to or from a server. A web browser handles HTTP requests in the background. You can also write programs that make HTTP requests. A  program called “curl” runs http requests from the terminal command line. Here are examples: https://reactivemusic.net/?p=5916

Response data

Data is usually returned in one of 3 formats:

  • JSON
  • XML
  • HTML

JSON is the preferred method because its easy to access the data structure.

Max HTTP requests

There are several ways to make HTTP requests in Max, but the best method is the js object: Here is the code that runs the GET request for the Vine API:

function get(url)
{
    var ajaxreq = new XMLHttpRequest();
    ajaxreq.open("GET", url);
    ajaxreq.onreadystatechange = readystatechange;
    ajaxreq.send();
}

function readystatechange()
{
    var rawtext = this._getResponseKey("body");
    var body = JSON.parse(rawtext);
    outlet(0, body.data.records[0].videoUrl);
}

 

The function: get() formats and sends an HTTP request using the URL passed in with the get message from Max. When the data is returned to Max, the readystatechange() function parses it and sends the URL of the most popular Vine video out the left outlet of the js object.

Playing Internet audio/video files in Max

The qt.movie object will play videos, with the URL passed in by the read message.

Unfortunately, qt.movie sends its audio to the system, not to Max. You can use Soundflower, or a virtual audio routing app, to get the audio back into Max.

MBTA API
Audio from video

https://reactivemusic.net/?p=12570

Video from audio

https://reactivemusic.net/?p=12570

Sonification of Vine videos

https://github.com/tkzic/max-projects/tree/master/maxvine

patch: maxvine-analyzer.maxpat (requires other files in the maxvine folder)

Steve Hensley example: local file: shensely_maxvine.maxpat

References

There is a large archive of examples here: Internet sensors: https://reactivemusic.net/?p=5859

Aggregators

There are API services that consolidate many API’s into one API. For example:

Scaling data

Look at the Max tutorial (built in to Max Help) called “Data : data scaling” It contains most of what you need to know to work with streams of data.

Curl examples: https://reactivemusic.net/?p=5916

Assignment

Algorithmic/generative music. Due in class next week.

 

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mchain

Build Markov in chains in real-time with Max

By Richard Dudas

http://www.richarddudas.com/software/

Screen Shot 2015-04-13 at 1.03.07 AM

Using the text processing example I built a 4th order Markov chain for “The Cat in The Hat” (by Dr. Seuss). Here is some of the result (it continues to infinity) with indentation added for readability:

The sat the sun is not shine.
It was to Sit! Sit!
And I sat in the house
All that?


How I wish We had something went BUMP! How I wish We did not shine.
It was to us jump! We looked!
The Cat in that cold to go out And wet to play.
So all we sat in the Hat! And he saw him!


Then we sat is wet to Sit! Sit!
And to go out
And the house
All that?


Why do was too wet And there little bit. And wet to go out
And there we saw him step in on that?
How I wish We sat is nothing at all.
So all we could do was too wet day.


So all we sat the house 
All that is fun there we can have Lots of good fun the mat!
We had something at all.
So wet to go out And the sun is wet to Sit! Sit!


And I said too wet to do I know it is not sunny!
Too we can have Lots of good funny!
Too wet And I sat is fun the house. We sat the house. We saw him!
The Cat is wet to us.

…

The help file patch allows real time Midi improvisation with a step sequencer style of playback:

Screen Shot 2015-04-13 at 1.12.49 AM

 

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12th root of 2

The note relationships in a chromatic scale are based on the 12th root of 2.

An octave has a ratio of 2. An octave is divided into 12 equal steps.

For example, to find the ratio of one semi-tone (half step), on a scientific calculator, use this button:

Screen Shot 2015-03-23 at 12.36.27 PM

Here’s the result where x = 2 and y = 12

Screen Shot 2015-03-23 at 12.47.48 PM

In a computer program, you could use the pow() function calculate 2 to the 1/12 power. Here’s an example in javascript:

Screen Shot 2015-03-23 at 12.44.03 PM

This Max patch shows the relationships between any two notes and how to calculate the pitch of a note based on the semi-tone interval. You might use it as a starting point to design your own scales. For example, a 13 note chromatic scale.  Or relationships based on randomness.

Screen Shot 2015-03-23 at 12.32.36 PM

Download

https://github.com/tkzic/max-projects 

folder: 12throotof2

patch: 12throotof2.maxpat