BB.AudioAnalyser

Extends BB.AudioBase
Defined in: src/BB.AudioAnalyser.js:11

A module for doing FFT ( Fast Fourier Transform ) analysis on audio

Index

Properties

Methods

Constructor

BB.AudioAnalyser
(
  • config
)

Defined in src/BB.AudioAnalyser.js:11

Parameters:

  • config Object

    A config object to initialize the Sampler, must contain a "context: AudioContext" property and can contain properties for fftSize, smoothing, maxDecibels and minDecibels ( see AnalyserNode for details )

Example:

in the example bellow "samp" is assumed to be an instanceof BB.AudioSampler ( represented by the Gain in the image below ), it's connected to the Analyser which is connected to the BB.Audio.context ( ie. AudioDestination ) by default


 BB.Audio.init();

 var fft = new BB.AudioAnalyser();
 // assuming samp is an instanceof BB.AudioSampler
 samp.connect( fft );


 // you can override fft's defaults by passing a config
 var fft = new BB.AudioAnalyser({
    context: BB.Audio.context[3],
    connect: BB.Audio.context[3].destination
 });

view basic BB.AudioAnalyser example

Properties

ctx AudioContext default:BB.Audio.context

Inherited from BB.AudioBase: src/BB.AudioBase.js:39

the Audio Context this derived from

gain GainNode private

Inherited from BB.AudioBase: src/BB.AudioBase.js:57

the "output" gain node ( use .volume, .setGain() to interface with this )

node AnalyserNode

Defined in src/BB.AudioAnalyser.js:45

the AnalyserNode itself

volume Number default:1

Inherited from BB.AudioBase: src/BB.AudioBase.js:89

the master volume (of output gain node)

There are no properties that match your current filter settings. You can change your filter settings in the index section on this page. index

Methods

connect
(
  • destination
  • output
  • input
)

Inherited from BB.AudioBase: src/BB.AudioBase.js:109

connects the Noise to a particular AudioNode or AudioDestinationNode

Parameters:

  • destination AudioNode

    the AudioNode or AudioDestinationNode to connect to

  • output Number

    which output of the the Noise do you want to connect to the destination

  • input Number

    which input of the destination you want to connect the Noise to

Example:


 BB.Audio.init();

 var node = new BB.AudioBase({
    volume: 0.75,
 });

  node.connect( exampleNode );
  // connected to both default BB.Audio.context && exampleNode
  // so if exampleNode is also connected to BB.Audio.context by default,
  // ...then you've got node connected to BB.Audio.context twice
...which looks like this ( where the first Gain is the Noise and the second is the exampleNode )

disconnect
(
  • destination
  • output
  • input
)

Inherited from BB.AudioBase: src/BB.AudioBase.js:153

diconnects the Noise from the node it's connected to

Parameters:

  • destination AudioNode

    what it's connected to

  • output Number

    the particular output number

  • input Number

    the particular input number
     BB.Audio.init();

     var node = new BB.AudioBase({
        volume: 0.75,
     });

     node.disconnect(); // disconnected from default BB.Audio.context
     node.connect( exampleNode ); // connected to exampleNode only
    ...which looks like this ( where the first Gain is the node and the second is the exampleNode )

getAmplitude ()

Defined in src/BB.AudioAnalyser.js:158

returns the averaged amplitude between both channels

getByteFrequencyData ()

Defined in src/BB.AudioAnalyser.js:78

returns an array with frequency byte data

Example:


 BB.Audio.init();

 var fft = new BB.AudioAnalyser();

 // then in a canvas draw loop...
 var fdata = fft.getByteFrequencyData();
 for (var i = 0; i < fdata.length; i++) {
   var value = fdata[i];
   var percent = value / 256;
   var height = HEIGHT percent;
   var offset = HEIGHT - height - 1;
   var barWidth = WIDTH/fdata.length;
   ctx.fillRect(i barWidth, offset, barWidth, height);
 };

getByteTimeDomainData ()

Defined in src/BB.AudioAnalyser.js:115

returns an array with time domain byte data

Example:


 BB.Audio.init();

 var fft = new BB.AudioAnalyser();

 // then in a canvas draw loop...
 var tdata = fft.getByteTimeDomainData();
 ctx.beginPath();
 var sliceWidth = WIDTH / tdata.length;
 var x = 0;
 for (var i = 0; i < tdata.length; i++) {
   var v = tdata[i] / 128.0;
   var y = v * HEIGHT/2;
   if(i===0) ctx.moveTo(x,y);
   else ctx.lineTo(x,y);
   x+=sliceWidth;
 }
 ctx.lineTo(WIDTH,HEIGHT/2);
 ctx.stroke();

getFloatFrequencyData ()

Defined in src/BB.AudioAnalyser.js:106

returns an array with frequency float data

getFloatTimeDomainData ()

Defined in src/BB.AudioAnalyser.js:148

returns an array with time domain float data

getPitch () Number

Defined in src/BB.AudioAnalyser.js:174

returns pitch frequency (float) in Hz, based on Chris Wilson

Returns: Number

pitch

getResampledBufferData ()

Defined in src/BB.AudioAnalyser.js:238

returns an multi-dimentional array ( one array per channel ) with resampled buffer data ( for drawing an entire waveform of a file )

Example:


 BB.Audio.init();

 var fft = new BB.AudioAnalyser();

 // then in a canvas draw loop...
 var tdata = fft.getResampledBufferData();
 ctx.beginPath();
 var sliceWidth = WIDTH / tdata.length;
 var x = 0;
 for (var i = 0; i < tdata.length; i++) {
   var v = tdata[i] / 128.0;
   var y = v * HEIGHT/2;
   if(i===0) ctx.moveTo(x,y);
   else ctx.lineTo(x,y);
   x+=sliceWidth;
 }
 ctx.lineTo(WIDTH,HEIGHT/2);
 ctx.stroke();

setGain
(
  • num
  • ramp
)

Inherited from BB.AudioBase: src/BB.AudioBase.js:197

sets the gain level of the node ( in a sense, master volume control )

Parameters:

  • num Number

    a float value, 1 being the default volume, below 1 decreses the volume, above one pushes the gain

  • ramp Number

    value in seconds for how quickly/slowly to ramp to the new value (num) specified

Example:


 BB.Audio.init();

 var node = new BB.AudioBase({
    volume: 0.75
 });

  node.setGain( 0.25, 2 ); // lower's volume from 0.75 to 0.25 in 2 seconds
// if no ramp value is needed, you could alternatively do
  node.volume = 0.5; // immediately jumps from 0.25 to 0.5

There are no methods that match your current filter settings. You can change your filter settings in the index section on this page. index