ml.miron.captcha.audio

Class Sample

java.lang.Object

ml.miron.captcha.audio.Sample

public class Sample
extends Object

Class representing a sound sample, typically read in from a file. Note that at this time this class only supports wav files with the following characteristics:

• Sample rate: 16KHz
• Sample size: 16 bits
• Channels: 1
• Signed: true
• Big Endian: false

Data files in other formats will cause an IllegalArgumentException to be thrown.

Author:

James Childers, Evgeny Mironenko

Field Summary

Fields

Modifier and Type	Field and Description
static AudioFormat	SC_AUDIO_FORMAT

Constructor Summary

Constructors

Constructor and Description
Sample(InputStream is) Creates a Sample with defined input stream.

Method Summary

Modifier and Type	Method and Description
byte[]	asByteArray() Return the interleaved samples as a byte[].
static byte[]	asByteArray(long sampleCount, double[] sample) Helper method to convert a double[] to a byte[] in a format that can be used by AudioInputStream.
void	decodeBytes(byte[] audioBytes, double[] audioSamples) Decodes bytes of audioBytes into audioSamples.
AudioInputStream	getAudioInputStream() Returns audio stream.
void	getChannelSamples(int channel, double[] interleavedSamples, double[] channelSamples) Extract samples of a particular channel from interleavedSamples and copy them into channelSamples.
AudioFormat	getFormat() Returns the current format audio.
double[]	getInterleavedSamples() Returns the array of interleaved samples.
double[]	getInterleavedSamples(long begin, long end, double[] samples) Get the interleaved decoded samples for all channels, from sample index begin (included) to sample index end (excluded) and copy them into samples.
long	getSampleCount() Return the number of samples of all channels.
void	getStereoSamples(double[] leftSamples, double[] rightSamples) Convenience method.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

SC_AUDIO_FORMAT

public static final AudioFormat SC_AUDIO_FORMAT

Constructor Detail

Sample

public Sample(InputStream is)

Creates a Sample with defined input stream.

Parameters:

is - input stream.

Method Detail

getAudioInputStream

public AudioInputStream getAudioInputStream()

Returns audio stream.

Returns:

see description.

getFormat

public AudioFormat getFormat()

Returns the current format audio.

Returns:

see description.

getSampleCount

public long getSampleCount()

Return the number of samples of all channels.

Returns:

see description.

getInterleavedSamples

public double[] getInterleavedSamples()

Returns the array of interleaved samples.

Returns:

see description.

getInterleavedSamples

public double[] getInterleavedSamples(long begin,
                                      long end,
                                      double[] samples)
                               throws IOException

Get the interleaved decoded samples for all channels, from sample index begin (included) to sample index end (excluded) and copy them into samples. end must not exceed getSampleCount(), and the number of samples must not be so large that the associated byte array cannot be allocated.

Parameters:

begin - begin index.

end - end index.

samples - array of samples.

Returns:

array of interleaved decoded samples.

Throws:

IOException - if something gone wrong.

getChannelSamples

public void getChannelSamples(int channel,
                              double[] interleavedSamples,
                              double[] channelSamples)

Extract samples of a particular channel from interleavedSamples and copy them into channelSamples.

Parameters:

channel - value of channel.

interleavedSamples - array of interleaved samples.

channelSamples - array of channel samples.

getStereoSamples

public void getStereoSamples(double[] leftSamples,
                             double[] rightSamples)
                      throws IOException

Convenience method. Extract left and right channels for common stereo files. leftSamples and rightSamples must be of size getSampleCount().

Parameters:

leftSamples - array of left samples.

rightSamples - array of right samples.

Throws:

IOException - if something gone wrong.

decodeBytes

public void decodeBytes(byte[] audioBytes,
                        double[] audioSamples)

Decodes bytes of audioBytes into audioSamples.

Parameters:

audioBytes - bytes of audio.

audioSamples - array of audio samples.

asByteArray

public final byte[] asByteArray()

Return the interleaved samples as a byte[].

Returns:

The interleaved samples.

asByteArray

public static byte[] asByteArray(long sampleCount,
                                 double[] sample)

Helper method to convert a double[] to a byte[] in a format that can be used by AudioInputStream. Typically this will be used with a Sample that has been modified from its original.

Parameters:

sampleCount - count of sample.

sample - array of samples.

Returns:

A byte[] representing a sample.

toString

public String toString()

Overrides:

toString in class Object