com.flagstone.transform
Class FSAudioData

java.lang.Object
  com.flagstone.transform.FSVideoObject
      com.flagstone.transform.FSAudioData

All Implemented Interfaces:

java.lang.Cloneable

public final class FSAudioData
extends FSVideoObject

FSAudioData is used to define sounds for a Flash Video (flv) file. It is similar in function to the FSDefineSound class.

Attributes
timestamp	The time in milliseconds at which the sound will be played. The timestamp is used exclusively for determining when sound or video will be played. Any internal timing information in the audio or video data is ignored.
format	The format of the sound data - PCM, ADPCM, MP3, NATIVE_PCM or NELLYMOSER.
playbackRate	The rate the sound will be played in Hertz: 5512, 11025, 22050 or 44100. Note: sounds encoded using the Nellymoser have a fixed playback rate of 8KHz.
playbackChannels	The number of channels in the sound, typically 1 (mono) or 2 (stereo).
playbackSampleSize	The number of bytes in a sample: 1 or 2.
sound	The sampled sound data.

Five encoded formats for the sound data are supported:

• NATIVE_PCM - uncompressed Pulse Code Modulated: samples are either 1 or 2 bytes. For two-byte samples the byte order is dependent on the platform on which the Flash Player is hosted. Sounds created on a platform which supports big-endian byte order will not be played correctly when listened to on a platform which supports little-endian byte order.
• PCM - uncompressed Pulse Code Modulated: samples are either 1 or 2 bytes with the latter presented in Little-Endian byte order. This ensures that sounds can be played across different platforms.
• ADPCM - compressed ADaptive Pulse Code Modulated: samples are encoded and compressed by comparing the difference between successive sound sample which dramatically reduces the size of the encoded sound when compared to the uncompressed PCM formats. Use this format whenever possible.
• MP3 - compressed MPEG Audio Layer-3.
• NELLYMOSER - compressed Nellymoser Asao format supporting low bit-rate sound for improving synchronisation between the sound and frame rate of movies.

HistoryThe FSAudioData class represents the FLV Tag with the Audio Data section from Macromedia's Flash (SWF) File Format Specification. It was added in Flash Video 1.

Field Summary

Fields inherited from class com.flagstone.transform.FSVideoObject

AudioData, length, MetaData, timestamp, type, VideoData

Constructor Summary

FSAudioData(int timestamp, int aFormat, int rate, int channels, int sampleSize, byte[] bytes)
Constructs an FSAudioData object specifying the parameters required to describe the sound.

Method Summary

void	appendDescription(java.lang.StringBuffer buffer, int depth)
java.lang.Object	clone() Creates a deep copy of the entire object.
boolean	equals(java.lang.Object anObject)
int	getFormat() Gets the compression format used, either FSSound.NATIVE_PCM, FSSound.PCM, FSSound.ADPCM, FSSound.MP3 or FSSound.NELLYMOSER.
int	getPlaybackChannels() Gets the number of sound channels, 1 (Mono) or 2 (Stereo).
int	getPlaybackRate() Gets the rate at which the sound will be played, in Hertz: 5512, 11025, 22050 or 44100.
int	getPlaybackSampleSize() Gets the size of an uncompressed sample in bytes.
byte[]	getSoundData() Gets the sound data.
void	setFormat(int encoding) Sets the encoding format used, either FSSound.NATIVE_PCM, FSSound.PCM, FSSound.ADPCM, FSSound.MP3 or FSSound.NELLYMOSER.
void	setPlaybackChannels(int channels) Sets the number of channels defined in the sound.
void	setPlaybackRate(int rate) Sets the sampling rate in Hertz.
void	setPlaybackSampleSize(int sampleSize) Sets the sample size in bytes.
void	setSoundData(byte[] bytes) Sets the sound data.

Methods inherited from class com.flagstone.transform.FSVideoObject

getTimestamp, getType, name, setTimestamp

Methods inherited from class java.lang.Object

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

Constructor Detail

FSAudioData

public FSAudioData(int timestamp,
                   int aFormat,
                   int rate,
                   int channels,
                   int sampleSize,
                   byte[] bytes)

Constructs an FSAudioData object specifying the parameters required to describe the sound.

Parameters:

timestamp - time in milliseconds from the start of the file that the sound will be played..

aFormat - the encoding format for the sound, either FSSound.NATIVE_PCM, FSSound.PCM, FSSound.ADPCM, FSSound.MP3 or FSSound.NELLYMOSER.

rate - the number of samples per second that the sound is played at, either 5512, 11025, 22050 or 44100.

channels - the number of channels in the sound, either 1 (Mono) or 2 (Stereo).

sampleSize - the size of an uncompressed sound sample in bits, either 8 or 16.

bytes - the sound data.

Method Detail

getFormat

public int getFormat()

Gets the compression format used, either FSSound.NATIVE_PCM, FSSound.PCM, FSSound.ADPCM, FSSound.MP3 or FSSound.NELLYMOSER.

Returns:

a constant defining the type of compression.

setFormat

public void setFormat(int encoding)

Sets the encoding format used, either FSSound.NATIVE_PCM, FSSound.PCM, FSSound.ADPCM, FSSound.MP3 or FSSound.NELLYMOSER.

Parameters:

encoding - the format for the sound.

getPlaybackRate

public int getPlaybackRate()

Gets the rate at which the sound will be played, in Hertz: 5512, 11025, 22050 or 44100. Note that the playback rate for Nellymoser encoded audio is fixed at 8Khz so the playback rate attribute has no effect.

Returns:

the rate at which the sound was sampled.

setPlaybackRate

public void setPlaybackRate(int rate)

Sets the sampling rate in Hertz. Must be one of: 5512, 11025, 22050 or 44100.

Parameters:

rate - the rate at which the sounds is played in Hz.

getPlaybackChannels

public int getPlaybackChannels()

Gets the number of sound channels, 1 (Mono) or 2 (Stereo).

Returns:

the number of channels.

setPlaybackChannels

public void setPlaybackChannels(int channels)

Sets the number of channels defined in the sound.

Parameters:

channels - the number of channels in the sound, either 1 (Mono) or 2 (Stereo).

getPlaybackSampleSize

public int getPlaybackSampleSize()

Gets the size of an uncompressed sample in bytes.

Returns:

the number of bytes per sample when the sound is uncompressed.

setPlaybackSampleSize

public void setPlaybackSampleSize(int sampleSize)

Sets the sample size in bytes. Must be either 1 or 2.

Parameters:

sampleSize - the size of sound samples in bytes.

getSoundData

public byte[] getSoundData()

Gets the sound data.

Returns:

an array of bytes containing the sampled sound.

setSoundData

public void setSoundData(byte[] bytes)

Sets the sound data.

Parameters:

bytes - the sound data.

clone

public java.lang.Object clone()

Description copied from class: FSVideoObject

Creates a deep copy of the entire object.

Overrides:

clone in class FSVideoObject

Returns:

a copy of the object.

equals

public boolean equals(java.lang.Object anObject)

Overrides:

equals in class FSVideoObject

appendDescription

public void appendDescription(java.lang.StringBuffer buffer,
                              int depth)

Overrides:

appendDescription in class FSVideoObject