fi.helsinki.cs.ohtu.mpeg2.audio.mpa
Class MP2Data

java.lang.Object
  fi.helsinki.cs.ohtu.mpeg2.audio.mpa.MP2Data

public class MP2Data
extends java.lang.Object

This class encodes compressed audio data to binary form. TODO: Add support for joint stereo.

Nested Class Summary

static class

MP2Data.Channel Represents a single audio channel.

Field Summary

private MP2Data.Channel[]	channels Audio channels for this audio data chunk
private int	jsbound From which sub-band the sub-band data is joint between channels
private QuantizationTables.QuantizationTable	qTable Quantization table for this audio data chunk

Constructor Summary

MP2Data(MP2Data.Channel[] channels, QuantizationTables.QuantizationTable qTable)
Creates a new AudioData instance from given channels using given quantization table.

MP2Data(MP2Data.Channel[] channels, QuantizationTables.QuantizationTable qTable, int jsbound)
Creates a new AudioData instance from given channels with a joint stereo bound, using a given quantization table.

MP2Data(MP2Data.Channel channel, QuantizationTables.QuantizationTable qTable)
Creates a new AudioData instance from given channel using given quanization table.

Method Summary

private void	encodeBitAllocation(BitOutputStream stream, CRC16 crc16) Writes the bit allocation of current audio data chunk to given stream and updates CRC-16 checksum.
private void	encodeSamples(BitOutputStream stream) Writes the samples of current audio data chunk to given stream.
private void	encodeScaleFactors(BitOutputStream stream, CRC16 crc16) Writes the scale factors of current audio data chunk to given stream and updates CRC-16 checksum.
void	writeTo(BitOutputStream stream) Writes this audio data chunk to given stream.
void	writeTo(BitOutputStream stream, CRC16 crc16) Writes this audio data chunk to given stream and updates CRC-16 checksum.

Methods inherited from class java.lang.Object

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

Field Detail

channels

private final MP2Data.Channel[] channels

Audio channels for this audio data chunk

jsbound

private final int jsbound

From which sub-band the sub-band data is joint between channels

qTable

private final QuantizationTables.QuantizationTable qTable

Quantization table for this audio data chunk

Constructor Detail

MP2Data

public MP2Data(MP2Data.Channel[] channels,
               QuantizationTables.QuantizationTable qTable,
               int jsbound)

Creates a new AudioData instance from given channels with a joint stereo bound, using a given quantization table. Starting from sub-band jsbound the first channel is used as a data source. The scale factor information is a slight exception as both the channels have their own scale factors. To keep things somewhat consistent, the joint sub-bands have to have equal bit allocations. Otherwise undefined behaviour will occur.

Parameters:

channels - the array of compressed audio channels

qTable - the quantization table for the audio samples

jsbound - the joint stereo bound of the sub-bands

MP2Data

public MP2Data(MP2Data.Channel[] channels,
               QuantizationTables.QuantizationTable qTable)

Creates a new AudioData instance from given channels using given quantization table.

Parameters:

channels - An array of compressed audio channels

qTable - Quantization table for the audio samples

MP2Data

public MP2Data(MP2Data.Channel channel,
               QuantizationTables.QuantizationTable qTable)

Creates a new AudioData instance from given channel using given quanization table.

Parameters:

channel - An audio channel

qTable - Quantization table for the audio samples

Method Detail

encodeBitAllocation

private void encodeBitAllocation(BitOutputStream stream,
                                 CRC16 crc16)
                          throws java.io.IOException

Writes the bit allocation of current audio data chunk to given stream and updates CRC-16 checksum.

Parameters:

stream - Stream in to which the bit allocation is written

crc16 - CRC-16 instance to update

Throws:

java.io.IOException

encodeScaleFactors

private void encodeScaleFactors(BitOutputStream stream,
                                CRC16 crc16)
                         throws java.io.IOException

Writes the scale factors of current audio data chunk to given stream and updates CRC-16 checksum.

Parameters:

stream - Stream in to which the scale factors are written

crc16 - CRC-16 instance to update

Throws:

java.io.IOException

encodeSamples

private void encodeSamples(BitOutputStream stream)
                    throws java.io.IOException

Writes the samples of current audio data chunk to given stream.

Parameters:

stream - Stream in to which the samples are written

Throws:

java.io.IOException

writeTo

public void writeTo(BitOutputStream stream,
                    CRC16 crc16)
             throws java.io.IOException

Writes this audio data chunk to given stream and updates CRC-16 checksum.

Parameters:

stream - Stream in to which this audio data chunk is written

crc16 - CRC-16 instance to update

Throws:

java.io.IOException

writeTo

public void writeTo(BitOutputStream stream)
             throws java.io.IOException

Writes this audio data chunk to given stream.

Parameters:

stream - Stream in to which this audio data chunk is written

Throws:

java.io.IOException