fi.helsinki.cs.ohtu.mpeg2
Class AccessUnit

java.lang.Object
  fi.helsinki.cs.ohtu.mpeg2.AccessUnit

Direct Known Subclasses:

VideoStream.VideoAccessUnit

public class AccessUnit
extends java.lang.Object

Represents a coded presentation of a presentation unit. A decoder handles its input in access units. Access units are queued into the decoder's input buffer and are removed after decoding.

The exact meaning of an access unit depends on a decoder. In case of audio, an access unit might be decoded into a frame of samples. A video decoder might generate a picture frame or field from an access unit.

Instances of this class are immutable. They can be shared safely between objects and threads.

Field Summary

private byte[]	data
private boolean	discont
private long	dts
private long	pts

Constructor Summary

AccessUnit(long pts, long dts, byte[] data)
Creates a new AccessUnit instance.

AccessUnit(long pts, long dts, byte[] data, boolean discont)
Creates a new AccessUnit instance.

Method Summary

byte	byteAt(int i) Returns the data byte at the specified index i.
long	getDts() Returns the decoding timestamp of this AccessUnit.
int	getLength() Returns the number of raw data bytes of this AccessUnit.
long	getPts() Returns the presentation timestamp of this AccessUnit.
boolean	isDiscontinuous() Returns whether decoding discontinuity precedes this AccessUnit.

Methods inherited from class java.lang.Object

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

Field Detail

pts

private final long pts

dts

private final long dts

data

private final byte[] data

discont

private final boolean discont

Constructor Detail

AccessUnit

public AccessUnit(long pts,
                  long dts,
                  byte[] data,
                  boolean discont)

Creates a new AccessUnit instance.

Parameters:

pts - the PTS for the access unit, in ticks of the 90kHz clock

dts - the DTS for the access unit, in ticks of the 90kHz clock

data - the data for the access unit

discont - true if a decoding discontinuity precedes the access unit

AccessUnit

public AccessUnit(long pts,
                  long dts,
                  byte[] data)

Creates a new AccessUnit instance.

Parameters:

pts - the PTS for the access unit, in ticks of the 90kHz clock

dts - the DTS for the access unit, in ticks of the 90kHz clock

data - the data for the access unit

Method Detail

isDiscontinuous

public boolean isDiscontinuous()

Returns whether decoding discontinuity precedes this AccessUnit.

Returns:

true in the presence of deconfing discontinuity

getPts

public long getPts()

Returns the presentation timestamp of this AccessUnit.

Returns:

the presentation timestamp

getDts

public long getDts()

Returns the decoding timestamp of this AccessUnit.

Returns:

the decoding timestamp

getLength

public int getLength()

Returns the number of raw data bytes of this AccessUnit.

Returns:

the number of raw data bytes

byteAt

public byte byteAt(int i)

Returns the data byte at the specified index i.

Parameters:

i - the index of the data byte

Returns:

the data byte