February 2013 - Page 3 of 5

February 22, 2013June 18, 2014

data recording

Thoughts on a streaming API project model with Max.

I’ve been trying to come up with generalized methods to handle the class of Max projects which read a stream of data from the Web, and use it to trigger events, for example, sound and graphics.

OSC is generally a good way to get data into Max from Web API’s. One issue with data streams, is that they do not always provide a constant flow. In some cases, this is what makes them musical. The rhythm of the flow becomes the rhythm of the music.

But in some cases we are vexed by too little flow or too much.

When the flow is too sparse, and the project requires a constant flow – the stream can be fattened up by using a [metro] object to output the current stream value at a higher frequency.

When the flow is too fast – you can use [speedlim] for numbers – but not for text data like tweets about cats, which seem to stream in like a flood. One solution is to use a data-recorder, like our modified CNMAT list recorder in the Irish Train project.

You would need separate access to the record and play ‘heads’ – so for example you could record in real time, but start playing back at a slower rate (while the recording continues). This is essentially a form of stream buffering. The data recorder approach would also allow you to use various algorithms to ‘thin’ the data – for example, to keep up with the real time rate, but by using less of the data.

[update] got this working with the modified CNMAT data recorder patch. It allows separate control of recording and playback, simultaneously.

patch is in tkzic/max teaching examples/ data-recorder-tester.maxpat

February 22, 2013

nodebox Osc in python

http://nodebox.net/code/index.php/OSC

February 22, 2013June 14, 2014

Osc in php

The Osc code from the stock market music project https://reactivemusic.net/?p=12029 is not really doing Osc.

But… it works well going from php->max. In the other direction its using a kluge of nc and an alarm clock shell program – to receive messages from Max in UDP, but its really kind of horrible – so I’m going to look again for an OSC library in php.

update 2/2013 This is hard to believe, but I haven’t yet found a real OSC libraries for php. Apparently php is so uncool, that nobody wants to write for it anymore. Anyway, the code above, works unidirectionally, so its of some use for existing php code.

Local files are max-php-osc-tester.maxpat and max-osc-play.php in tkzic/api

Analysis that might help with parsing:

from Captain Caveman

http://forum.cockos.com/showthread.php?t=99076

February 22, 2013February 26, 2013

Csound in Pure Data on Raspberry-Pi controlled by touchOsc

Its starting to seem like the R-Pi is turning out to be a real musical instrument.

February 21, 2013June 22, 2014

Feels Like We Only Go Backwards

By Tame Impala

recommended by John Drew

February 21, 2013February 26, 2013

Twitter streaming php decoder breaks out individual tweets

This code was adapted (i.e. stolen verbatim) from a stackoverflow post by drew010

http://stackoverflow.com/questions/10337984/using-the-curl-output

Here’s the code. It solves a huge problem for the class of projects which need to grab a large amount of tweets in real time to either save in a database, or trigger some action.

My version of the code is in tkzic/api/twitterStream1.php

<?php

$USERNAME = 'youruser';
$PASSWORD = 'yourpass';
$QUERY    = 'nike';

/**
 * Called every time a chunk of data is read, this will be a json encoded message
 * 
 * @param resource $handle The curl handle
 * @param string   $data   The data chunk (json message)
 */
function writeCallback($handle, $data)
{
    /*
    echo "-----------------------------------------------------------\n";
    echo $data;
    echo "-----------------------------------------------------------\n";
    */

    $json = json_decode($data);
    if (isset($json->user) && isset($json->text)) {
        echo "@{$json->user->screen_name}: {$json->text}\n\n";
    }

    return strlen($data);
}

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, 'https://stream.twitter.com/1/statuses/filter.json?track=' . urlencode($QUERY));
curl_setopt($ch, CURLOPT_USERPWD, "$USERNAME:$PASSWORD");
curl_setopt($ch, CURLOPT_WRITEFUNCTION, 'writeCallback');
curl_setopt($ch, CURLOPT_TIMEOUT, 20); // disconnect after 20 seconds for testing
curl_setopt($ch, CURLOPT_VERBOSE, 1);  // debugging
curl_setopt($ch, CURLOPT_ENCODING,  'gzip, deflate'); // req'd to get gzip
curl_setopt($ch, CURLOPT_USERAGENT, 'tstreamer/1.0'); // req'd to get gzip

curl_exec($ch); // commence streaming

$info = curl_getinfo($ch);

var_dump($info);

February 20, 2013

official curl tutorial

http://curl.haxx.se/docs/httpscripting.html

February 20, 2013February 26, 2013

Csound in Pure Data on Raspberry-Pi

Today I got Csound running inside Pure Data (using the [csoundapi~] object) on Raspberry-Pi.

These instructions assume you have already installed pd-extended on R-Pi. See this post to learn how. https://reactivemusic.net/?p=4930

Install Csound

# sudo apt-get install cloud

Install csoundapi~

# sudo apt-get install pd-csound

Copy csoundapi~ library into the pd-extended extras folder

# cd /usr/lib/pd/csound/extras
# sudo cp csoundapi~.pd_linux ../../pd-extended/extra

Here’s a test patch:

Here’s the Csound source file (should be in the same folder as the test patch)

<CsoundSynthesizer>
<CsOptions>
</CsOptions>
<CsInstruments>
;Example by Joachim Heintz

sr = 44100
nchnls = 2
0dbfs = 1
ksmps = 8

giSine    ftgen     0, 0, 2^10, 10, 1

instr 1
kFreq     invalue   "freq"
kAmp      invalue   "amp"
aSin      oscili    kAmp, kFreq, giSine
          outs      aSin, aSin
endin

</CsInstruments>
<CsScore>
i 1 0 10000
</CsScore>
</CsoundSynthesizer>

Here are the source files:

http://zerokidz.com/rpi/csound/cstest2.pd

http://zerokidz.com/rpi/csound/control.csd

Here’s the command line to run the test: