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jssound module

Support wav, aiff, au, voc, sd2, flac, ... sound format using libsndfile and ogg vorbis using libogg and libvorbis.

• jssound module
• jssound static members
• Note
• Examples
• class jssound::
• constructor
• Methods
• Read
• Properties
• inputStream
• bits
• rate
• channels
• frames
• class jssound::
• constructor
• Methods
• Read
• Properties
• inputStream
• bits
• rate
• channels
• frames

jssound static members

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DecodeOggVorbis

_soundObject DecodeOggVorbis( stream )

Decodes a ogg vorbis sample to a sound object.

arguments:

1. _streamObject stream: any object that has a Read function or that supports the NIStreamRead Native Interface ( file, socket, new Stream(buffer), ... ). For further details about stream objects, see jslang::Stream object and NativeInterface mechanism.

return value:

A sound object in a 16-bit per sample format.

example:

  LoadModule('jsstd');
  LoadModule('jsio');
  LoadModule('jssound');

  var file = new File('41_30secOgg-q0.ogg');
  var buffer = file.content;
  var stream = new Stream(buffer);
  var mySoundObject = DecodeOggVorbis(stream);
  Print('sample length: ', mySoundObject.length, '\n');

DecodeSound

_soundObject DecodeSound( stream )

Decodes a sample from any supported sound format to a sound object.

arguments:

1. _streamObject stream: any object that has a Read function or that supports the NIStreamRead Native Interface ( file, socket, new Stream(buffer), ... ). For further details about stream objects, see jslang::Stream object and native interface mechanism.

return value:

A sound object in a 16-bit per sample format.

SplitChannels

_Array SplitChannels( sound )

Split channels of the sound into an Array of monaural sound object.

arguments:

1. _soundObject sound

return value:

An array that contains each individual channel of the sound.

Note

SoundObject concatenation can be achieved using the concat() method. This works becuase a sound object is a Blob with some extra properties.

Examples

example 1:

 LoadModule('jsstd');
 LoadModule('jsio');
 LoadModule('jssound');

 var file = new File('41_30secOgg-q0.wav');
 file.Open('r');
 var pcm = DecodeSound(file);
 file.Close();
 Print('sample length: '+pcm.length, '\n');

example 2:

 LoadModule('jsstd');
 LoadModule('jsio');
 LoadModule('jssound');

 var file = new File('41_30secOgg-q0.wav');
 var buffer = file.content;
 var stream = new Stream(buffer);
 var pcm = DecodeSound(stream);

 Print('sample length: '+pcm.length, '\n');

class jssound::OggVorbisDecoder

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The OggVorbisDecoder support ogg vorbis data format decoding.

constructor

constructor( stream )

Creates a new OggVorbisDecoder object. Seekable and non-seekable streams are supported.

arguments:

1. _streamObject stream: is the data stream from where encoded data are read from.

example:

  LoadModule('jsstd');
  LoadModule('jsio');
  LoadModule('jssound');
  var file = new File('41_30secOgg-q0.ogg'); // file: http://xiph.org/vorbis/listen.html
  file.Open('r');
  var dec = new OggVorbisDecoder( file );
  Print( dec.bits, '\n' );
  Print( dec.channels, '\n' );
  Print( dec.rate, '\n' );
  do {
   var block = dec.Read(10000);
   Print( 'frames: '+block.frames, '\n' );
  } while(block);

Methods

Read

_soundObject Read( [frames] )

Decodes a piece of audio data. If frames argument is omited, the whole stream is decoded.

arguments:

1. _integer frames: the number of frames to decode. A frame is a sample of sound.

return value:

A Blob object that has the following properties set: bits, rate, channels, frames

beware:

If all data has been decoded and the Read function is called again, the return expression is evaluated to ALSE.

example:

  LoadModule('jsstd');
  LoadModule('jsio');
  LoadModule('jssound');
  var file = new File('41_30secOgg-q0.ogg'); // file: http://xiph.org/vorbis/listen.html
  file.Open('r');
  var dec = new OggVorbisDecoder( file );
  var block = dec.Read(10000);
  Print( 'rezolution: '+block.bits+' per channel', '\n' );
  Print( block.channels == 2 ? 'stereo' : 'mono', '\n' );
  Print( block.rate+' frames/seconds', '\n' );
  Print( 'time: '+(block.frames/block.rate)+' seconds', '\n' );

Properties

inputStream

object inputStream

Is the stream object where encoded audio data are read from.

bits

_integer bits

Is the number of bits per frame and per channel.

rate

_integer rate

Is the number of frames per seconds of the sound.

channels

_integer channels

Is the number of channels of the sound. 1 is mono, 2 is stereo.

frames

_integer frames

Is the length (in frames) of the sound. To compute the duration of the sound, use (frames/rate)

class jssound::SoundFileDecoder

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The SoundFileDecoder support various data format decoding. Main supported formats are: wav, aiff, au, voc, sd2, flac, ... For more information about supported formats, see http://www.mega-nerd.com/libsndfile/

constructor

constructor( stream )

Creates a new SoundFileDecoder object. Only seekable streams are supported.

arguments:

1. _streamObject stream: is the data stream from where encoded data are read from.

example:

  LoadModule('jsstd');
  LoadModule('jsio');
  LoadModule('jssound');
  var file = new File('41_30secOgg-q0.wav'); // file: http://xiph.org/vorbis/listen.html
  file.Open('r');
  var dec = new SoundFileDecoder( file );
  Print( dec.bits, '\n' );
  Print( dec.channels, '\n' );
  Print( dec.rate, '\n' );
  do {
   var block = dec.Read(10000);
   Print( 'frames: '+block.frames, '\n' );
  } while(block);

Methods

Read

_soundObject Read( [frames] )

Decodes a piece of audio data. If frames argument is omited, the whole stream is decoded.

arguments:

1. _integer frames: the number of frames to decode. A frame is a sample of sound.

return value:

A Blob object that has the following properties set: bits, rate, channels, frames

beware:

If all data has been decoded and the Read function is called again, the return expression is evaluated to ALSE.

example:

  LoadModule('jsstd');
  LoadModule('jsio');
  LoadModule('jssound');
  var file = new File('41_30secOgg-q0.wav'); // file: http://xiph.org/vorbis/listen.html
  file.Open('r');
  var dec = new SoundFileDecoder( file );
  var block = dec.Read(10000);
  Print( 'rezolution: '+block.bits+' per channel', '\n' );
  Print( block.channels == 2 ? 'stereo' : 'mono', '\n' );
  Print( block.rate+' frames/seconds', '\n' );
  Print( 'time: '+(block.frames/block.rate)+' seconds', '\n' );

Properties

inputStream

object inputStream

Is the stream object where encoded audio data are read from.

bits

_integer bits

Is the number of bits per frame and per channel.

rate

_integer rate

Is the number of frames per seconds of the sound.

channels

_integer channels

Is the number of channels of the sound. 1 is mono, 2 is stereo.

frames

_integer frames

Is the length (in frames) of the sound. To compute the duration of the sound, use (frames/rate)

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