jj2000.j2k.codestream.reader

Class PktDecoder

java.lang.Object

jj2000.j2k.codestream.reader.PktDecoder

All Implemented Interfaces:

StdEntropyCoderOptions

public class PktDecoder
extends Object
implements StdEntropyCoderOptions

This class is used to read packet's head and body. All the members must be re-initialized at the beginning of each tile thanks to the restart() method.

Field Summary

Fields

Modifier and Type	Field and Description
private PktHeaderBitReader	bin The wrapper to read bits for the packet heads
private Vector[]	cblks List of code-blocks found in last read packet head (one list per subband)
private int	cQuit The component in which the ncb quit condition was reached
private DecoderSpecs	decSpec Reference to decoder specifications
private RandomAccessIO	ehs Reference to the stream where to read from
private boolean	ephUsed Whether or not EPH marker are used
private HeaderDecoder	hd Reference to the HeaderDecoder
private int	INIT_LBLOCK Initial value of the state variable associated with code-block length.
private boolean	isTruncMode True if truncation mode is used.
private int[][][][][]	lblock Lblock value used to read code size information in each packet head: 1st dim: component index. 2nd dim: resolution level index. 3rd dim: subband index. 4th/5th dim: code-block index (vert.
private int	maxCB Maximum number of codeblocks to read before ncb quit condition is reached
private int	nc The number of components
private int	ncb Number of codeblocks encountered.
private boolean	ncbQuit Flag indicating whether ncb quit condition has been reached
private int	nl Number of layers in t he current tile
private Point[][]	numPrec Maximum number of precincts : 1st dim: component index. 2nd dim: resolution level index.
private int	pktIdx Index of the current packet in the tile.
private boolean	pph Flag indicating whether packed packet header was used for this tile
private ByteArrayInputStream	pphbais The packed packet header if it was used
private PrecInfo[][][]	ppinfo Array containing the coordinates, width, height, indexes, ...
private int	rQuit The resolution in which the ncb quit condition was reached
private boolean	sopUsed Whether or not SOP marker segment are used
private int	sQuit The subband in which the ncb quit condition was reached
private BitstreamReaderAgent	src Reference to the codestream reader agent
private int	tIdx Index of the current tile
private int	tQuit The tile in which the ncb quit condition was reached
private TagTreeDecoder[][][][]	ttIncl Tag tree used to read inclusion informations in packet's head: 1st dim: component index. 2nd dim: resolution level index. 3rd dim: precinct index. 4th dim: subband index.
private TagTreeDecoder[][][][]	ttMaxBP Tag tree used to read bit-depth information in packet's head: 1st dim: component index. 2nd dim: resolution level index. 3rd dim: precinct index. 4th dim: subband index.
private int	xQuit The x position of the last code block before ncb quit reached
private int	yQuit The y position of the last code block before ncb quit reached

Fields inherited from interface jj2000.j2k.entropy.StdEntropyCoderOptions

FIRST_BYPASS_PASS_IDX, MAX_CB_AREA, MAX_CB_DIM, MIN_CB_DIM, NUM_EMPTY_PASSES_IN_MS_BP, NUM_NON_BYPASS_MS_BP, NUM_PASSES, OPT_BYPASS, OPT_PRED_TERM, OPT_RESET_MQ, OPT_SEG_SYMBOLS, OPT_TERM_PASS, OPT_VERT_STR_CAUSAL, STRIPE_HEIGHT

Constructor Summary

Constructors

Constructor and Description
PktDecoder(DecoderSpecs decSpec, HeaderDecoder hd, RandomAccessIO ehs, BitstreamReaderAgent src, boolean isTruncMode, int maxCB) Creates an empty PktDecoder object associated with given decoder specifications and HeaderDecoder.

Method Summary

Methods

Modifier and Type	Method and Description
private void	fillPrecInfo(int c, int r, int mdl) Retrives precincts and code-blocks coordinates in the given resolution, level and component.
int	getNumPrecinct(int c, int r) Gets the number of precincts in a given component and resolution level.
int	getPPX(int t, int c, int r) Returns the precinct partition width for the specified component, resolution level and tile.
int	getPPY(int t, int c, int rl) Returns the precinct partition height for the specified component, resolution level and tile.
PrecInfo	getPrecInfo(int c, int r, int p) Get PrecInfo instance of the specified resolution level, component and precinct.
void	readEPHMarker(PktHeaderBitReader bin) Try to read an EPH marker.
boolean	readPktBody(int l, int r, int c, int p, CBlkInfo[][][] cbI, int[] nb) Reads specificied packet body in order to find offset of each code-block's piece of codeword.
boolean	readPktHead(int l, int r, int c, int p, CBlkInfo[][][] cbI, int[] nb) Read specified packet head and found length of each code-block's piece of codewords as well as number of skipped most significant bit-planes.
boolean	readSOPMarker(int[] nBytes, int p, int c, int r) Try to read a SOP marker and check that its sequence number if not out of sequence.
CBlkInfo[][][][][]	restart(int nc, int[] mdl, int nl, CBlkInfo[][][][][] cbI, boolean pph, ByteArrayInputStream pphbais) Re-initialize the PktDecoder instance at the beginning of a new tile.

Methods inherited from class java.lang.Object

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

Field Detail

src

private BitstreamReaderAgent src

Reference to the codestream reader agent

pph

private boolean pph

Flag indicating whether packed packet header was used for this tile

pphbais

private ByteArrayInputStream pphbais

The packed packet header if it was used

decSpec

private DecoderSpecs decSpec

Reference to decoder specifications

hd

private HeaderDecoder hd

Reference to the HeaderDecoder

INIT_LBLOCK

private final int INIT_LBLOCK

Initial value of the state variable associated with code-block length.

See Also:

Constant Field Values

bin

private PktHeaderBitReader bin

The wrapper to read bits for the packet heads

ehs

private RandomAccessIO ehs

Reference to the stream where to read from

numPrec

private Point[][] numPrec

Maximum number of precincts :

• 1st dim: component index.
• 2nd dim: resolution level index.

tIdx

private int tIdx

Index of the current tile

ppinfo

private PrecInfo[][][] ppinfo

Array containing the coordinates, width, height, indexes, ... of the precincts in the current tile:

• 1st dim: component index.
• 2nd dim: resolution level index.
• 3rd dim: precinct index.

lblock

private int[][][][][] lblock

Lblock value used to read code size information in each packet head:

• 1st dim: component index.
• 2nd dim: resolution level index.
• 3rd dim: subband index.
• 4th/5th dim: code-block index (vert. and horiz.).

ttIncl

private TagTreeDecoder[][][][] ttIncl

Tag tree used to read inclusion informations in packet's head:

• 1st dim: component index.
• 2nd dim: resolution level index.
• 3rd dim: precinct index.
• 4th dim: subband index.

ttMaxBP

private TagTreeDecoder[][][][] ttMaxBP

Tag tree used to read bit-depth information in packet's head:

• 1st dim: component index.
• 2nd dim: resolution level index.
• 3rd dim: precinct index.
• 4th dim: subband index.

nl

private int nl

Number of layers in t he current tile

nc

private int nc

The number of components

sopUsed

private boolean sopUsed

Whether or not SOP marker segment are used

ephUsed

private boolean ephUsed

Whether or not EPH marker are used

pktIdx

private int pktIdx

Index of the current packet in the tile. Used with SOP marker segment

cblks

private Vector[] cblks

List of code-blocks found in last read packet head (one list per subband)

ncb

private int ncb

Number of codeblocks encountered. used for ncb quit condition

maxCB

private int maxCB

Maximum number of codeblocks to read before ncb quit condition is reached

ncbQuit

private boolean ncbQuit

Flag indicating whether ncb quit condition has been reached

tQuit

private int tQuit

The tile in which the ncb quit condition was reached

cQuit

private int cQuit

The component in which the ncb quit condition was reached

sQuit

private int sQuit

The subband in which the ncb quit condition was reached

rQuit

private int rQuit

The resolution in which the ncb quit condition was reached

xQuit

private int xQuit

The x position of the last code block before ncb quit reached

yQuit

private int yQuit

The y position of the last code block before ncb quit reached

isTruncMode

private boolean isTruncMode

True if truncation mode is used. False if it is parsing mode

Constructor Detail

PktDecoder

public PktDecoder(DecoderSpecs decSpec,
          HeaderDecoder hd,
          RandomAccessIO ehs,
          BitstreamReaderAgent src,
          boolean isTruncMode,
          int maxCB)

Creates an empty PktDecoder object associated with given decoder specifications and HeaderDecoder. This object must be initialized thanks to the restart method before being used.

Parameters:

decSpec - The decoder specifications.

hd - The HeaderDecoder instance.

ehs - The stream where to read data from.

src - The bit stream reader agent.

isTruncMode - Whether or not truncation mode is required.

maxCB - The maximum number of code-blocks to read before ncbquit

Method Detail

restart

public CBlkInfo[][][][][] restart(int nc,
                         int[] mdl,
                         int nl,
                         CBlkInfo[][][][][] cbI,
                         boolean pph,
                         ByteArrayInputStream pphbais)

Re-initialize the PktDecoder instance at the beginning of a new tile.

Parameters:

nc - The number of components in this tile

mdl - The maximum number of decomposition level in each component of this tile

nl - The number of layers in this tile

cbI - The code-blocks array

pph - Flag indicating whether packed packet headers was used

pphbais - Stream containing the packed packet headers

fillPrecInfo

private void fillPrecInfo(int c,
                int r,
                int mdl)

Retrives precincts and code-blocks coordinates in the given resolution, level and component. Finishes TagTreeEncoder initialization as well.

Parameters:

c - Component index.

r - Resolution level index.

mdl - Number of decomposition level in component c.

getNumPrecinct

public int getNumPrecinct(int c,
                 int r)

Gets the number of precincts in a given component and resolution level.

Parameters:

c - Component index

r - Resolution index

readPktHead

public boolean readPktHead(int l,
                  int r,
                  int c,
                  int p,
                  CBlkInfo[][][] cbI,
                  int[] nb)
                    throws IOException

Read specified packet head and found length of each code-block's piece of codewords as well as number of skipped most significant bit-planes.

Parameters:

l - layer index

r - Resolution level index

c - Component index

p - Precinct index

cbI - CBlkInfo array of relevant component and resolution level.

nb - The number of bytes to read in each tile before reaching output rate (used by truncation mode)

Returns:

True if specified output rate or EOF is reached.

Throws:

IOException

readPktBody

public boolean readPktBody(int l,
                  int r,
                  int c,
                  int p,
                  CBlkInfo[][][] cbI,
                  int[] nb)
                    throws IOException

Reads specificied packet body in order to find offset of each code-block's piece of codeword. This use the list of found code-blocks in previous red packet head.

Parameters:

l - layer index

r - Resolution level index

c - Component index

p - Precinct index

cbI - CBlkInfo array of relevant component and resolution level.

nb - The remainding number of bytes to read from the bit stream in each tile before reaching the decoding rate (in truncation mode)

Returns:

True if decoding rate is reached

Throws:

IOException

getPPX

public final int getPPX(int t,
         int c,
         int r)

Returns the precinct partition width for the specified component, resolution level and tile.

Parameters:

t - the tile index

c - The index of the component (between 0 and C-1)

r - The resolution level, from 0 to L.

Returns:

the precinct partition width for the specified component, resolution level and tile.

getPPY

public final int getPPY(int t,
         int c,
         int rl)

Returns the precinct partition height for the specified component, resolution level and tile.

Parameters:

t - the tile index

c - The index of the component (between 0 and C-1)

rl - The resolution level, from 0 to L.

Returns:

the precinct partition height in the specified component, for the specified resolution level, for the current tile.

readSOPMarker

public boolean readSOPMarker(int[] nBytes,
                    int p,
                    int c,
                    int r)
                      throws IOException

Try to read a SOP marker and check that its sequence number if not out of sequence. If so, an error is thrown.

Parameters:

nBytes - The number of bytes left to read from each tile

p - Precinct index

r - Resolution level index

c - Component index

Throws:

IOException

readEPHMarker

public void readEPHMarker(PktHeaderBitReader bin)
                   throws IOException

Try to read an EPH marker. If it is not possible then an Error is thrown.

Parameters:

bin - The packet header reader to read the EPH marker from

Throws:

IOException

getPrecInfo

public PrecInfo getPrecInfo(int c,
                   int r,
                   int p)

Get PrecInfo instance of the specified resolution level, component and precinct.

Parameters:

c - Component index.

r - Resolution level index.

p - Precinct index.