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 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

Modifier and Type	Method and Description
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(jj2000.j2k.codestream.reader.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

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

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(jj2000.j2k.codestream.reader.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.