AudioWriteBuffer
ptolemy.actor.lib.javasound.AudioWriteBuffer

This actor writes audio samples to a buffer and saves the buffer to a sound file on wrapup. In each iteration, if there is a token available on the <i>data</i> and <i>address</i> ports, then the data DoubleToken is written to the buffer location specified by the address IntToken. The valid address range is 0 to <i>bufferLength</i> -1. If an invalid address is specified, then the data value will be ignored and no data will be written. The audio samples in the buffer will be written to the sound file specified by the <i>pathName</i> parameter on wrapup. <p> Any existing file with the same name will be silently overwritten. The data port is of type DoubleToken. Each DoubleToken read from the data port represents one sample of the audio data and should be in the range [-1.0, 1.0]. Any samples that are outside of this range will be hard-clipped to fall within this range before they are written to the sound file. Single channel (mono) audio is supported but stereo is not supported. <p> The following parameters should be set to specify the format of the file to write. In all cases, an exception is thrown if an illegal parameter value is used. Note that if a parameter is changed while audio writing is active, all data written so far will be saved, and the sound file will be closed. Subsequent audio samples will then be written to a new sound file with the new parameter values. <p> <ul> <li><i>pathName</i> should be set to the name of the output file. Any existing file with the same name will be silently overwritten. Relative filenames are supported. The default value is "outfile.wav". The audio format to use is determined by the file extension. E.g., "outfile.wav" will create a WAV format file. The supported file formats are AU, WAV, and, AIFF. For example, to write samples to a Sun AU format file with the name "test.au" in the directory "c:\tmp", this parameter should be set to the value c:\tmp\test.au. To write samples to a file with name "test.au" in the current directory, this parameter should be set to the value test.au. <li><i>channels</i> should be set to desired number of audio channels. Allowable values are 1 (for mono) and 2 (for stereo). The default value is 1. Only single-channel audio is currently supported. This limitation will be removed in a future version of this actor. <li><i>sampleRate</i> should be set to desired sample rate, in Hz. The DoubleTokens read in by this actor will be interpreted as having this sample rate. Allowable values are 8000, 11025, 22050, 44100, and 48000. The default value is 8000. <li><i>bitsPerSample</i> should be set to desired bit resolution. Allowable values are 8 and 16. The default value is 16. </ul> <p> There are security issues involved with accessing files and audio resources in applets. By default, applets are not allowed to write files. The .java.policy file may be modified to grant applets more privileges. <p> Note: Requires Java 2 v1.3.0 or later. <p>FIXME: this should extend AudioWriter

Author(s): Brian K. Vogel
Version:$Id: AudioWriteBuffer.doc.html,v 1.1 2006/02/22 18:40:26 mangal Exp $
Pt.Proposed Rating:Red (vogel)
Pt.Accepted Rating:Red (vogel)


address
The address port, which is a multiport.
data
The data port, which is a multiport.


bufferLength
The length of the audio buffer to use. The default value is 8000.
overwrite
The write mode to use. If this parameter is set to true, then a write to a buffer element overwrites the old value in the buffer. Otherwise, a write adds the new value to the old value of the buffer element.
sampleRate
The desired sample rate to use, in Hz. Valid values include: 8000, 11025, 22050, 44100, and 48000. The default value of the sample rate is an IntToken equal to 8000. <p> An exception will be thrown if an illegal value is used.
bitsPerSample
The desired number of bits per sample. The default value is an IntToken equal to 16. Supported values are 8 and 16. An exception will be thrown if an illegal value is used.
channels
The number of audio channels to use. Supported values are 1 (single channel) and 2 (stereo). The default value is an IntToken equal to 1. An exception will be thrown if an illegal value is used.