org.daisy.pipeline.audio

Class AudioUtils

java.lang.Object

org.daisy.pipeline.audio.AudioUtils

public final class AudioUtils
extends Object

Method Summary

Modifier and Type	Method and Description
static AudioInputStream	concat(Iterable<AudioInputStream> streams) Concatenate a sequence of AudioInputStream into a single AudioInputStream.
static AudioInputStream	convertAudioStream(AudioFormat newFormat, AudioInputStream stream) Convert audio from one format to another.
static AudioInputStream	createAudioStream(AudioFormat format, byte[] data) Create an AudioInputStream from an AudioFormat and the audio data.
static AudioInputStream	createAudioStream(AudioFormat format, ByteArrayInputStream data)
static AudioInputStream	createAudioStream(InputStream stream) Create a AudioInputStream from a InputStream.
static AudioInputStream	createSilence(AudioFormat format, long frames)
static AudioInputStream	createSilence(PCMAudioFormat format, Duration duration)
static Duration	getDuration(AudioFormat format, int bytes)
static Duration	getDuration(AudioInputStream stream) Get the duration of a PCM encoded audio stream.
static long	getLengthInFrames(PCMAudioFormat format, Duration duration)
static boolean	isPCM(AudioFormat format)
static Iterable<AudioInputStream>	split(AudioInputStream stream, Duration... splitPoints) Split a AudioInputStream into a sequence of AudioInputStream.
static Iterable<AudioInputStream>	split(AudioInputStream stream, long... splitPoints)

Methods inherited from class java.lang.Object

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

Method Detail

createAudioStream

public static AudioInputStream createAudioStream(AudioFormat format,
                                                 byte[] data)

Create an AudioInputStream from an AudioFormat and the audio data.

Parameters:

format - Expected to be PCM.

createAudioStream

public static AudioInputStream createAudioStream(AudioFormat format,
                                                 ByteArrayInputStream data)

createAudioStream

public static AudioInputStream createAudioStream(InputStream stream)
                                          throws UnsupportedAudioFileException,
                                                 IOException

Create a AudioInputStream from a InputStream. This is to work around a bug in AudioSystem which may return AudioInputStream with a wrong AudioInputStream.getFrameLength().

Throws:

UnsupportedAudioFileException

IOException

getDuration

public static Duration getDuration(AudioInputStream stream)

Get the duration of a PCM encoded audio stream.

Throws:

IllegalArgumentException - if format is not PCM encoded with specified frame rate.

getDuration

public static Duration getDuration(AudioFormat format,
                                   int bytes)

Throws:

IllegalArgumentException - if format is not PCM encoded with specified frame rate and frame size.

getLengthInFrames

public static long getLengthInFrames(PCMAudioFormat format,
                                     Duration duration)

Returns:

the number of frames needed to contain the given duration of audio.

concat

public static AudioInputStream concat(Iterable<AudioInputStream> streams)

Concatenate a sequence of AudioInputStream into a single AudioInputStream.

Parameters:

streams - Must be streams with the same (PCM) audio format.

split

public static Iterable<AudioInputStream> split(AudioInputStream stream,
                                               Duration... splitPoints)

Split a AudioInputStream into a sequence of AudioInputStream.

Parameters:

stream - Must be PCM encoded. AudioInputStream.getFrameLength() must return the actual number of available frames in the stream.

splitPoints - Are relative to the beginning of the stream.

Returns:

A sequence of streams. The number of streams is one more than the number of split points. The durations are approximately (apart from rounding errors due to sampling) the time between the split points.

Throws:

IllegalArgumentException - if a negative split point is provided, a split point exceeds the total length of the input stream, or a split point is not greater than or equal to the preceding split point ,and also if the audio format is not PCM encoded with specified frame rate and frame size.

split

public static Iterable<AudioInputStream> split(AudioInputStream stream,
                                               long... splitPoints)

createSilence

public static AudioInputStream createSilence(PCMAudioFormat format,
                                             Duration duration)

Parameters:

duration - must not be negative

Returns:

null if duration is too short

createSilence

public static AudioInputStream createSilence(AudioFormat format,
                                             long frames)

Parameters:

format - must be PCM encoded

frames - must not be negative

Returns:

null if frames is 0

convertAudioStream

public static AudioInputStream convertAudioStream(AudioFormat newFormat,
                                                  AudioInputStream stream)

Convert audio from one format to another.

isPCM

public static boolean isPCM(AudioFormat format)