jj2000.j2k.codestream.writer
Class HeaderEncoder

java.lang.Object
  |
  +--jj2000.j2k.codestream.writer.HeaderEncoder

All Implemented Interfaces:

Markers, StdEntropyCoderOptions

public class HeaderEncoder

extends java.lang.Object

implements Markers, StdEntropyCoderOptions

This class writes almost of the markers and marker segments in main header and in tile-part headers. It is created by the run() method of the Encoder instance.

A marker segment includes a marker and eventually marker segment parameters. It is designed by the three letter code of the marker associated with the marker segment. JPEG 2000 part I defines 6 types of markers:

• Delimiting : SOC,SOT,SOD,EOC (written in FileCodestreamWriter).
• Fixed information: SIZ.
• Functional: COD,COC,RGN,QCD,QCC,POC.
• In bit-stream: SOP,EPH.
• Pointer: TLM,PLM,PLT,PPM,PPT.
• Informational: CRG,COM.

Main Header is written when Encoder instance calls encodeMainHeader whereas tile-part headers are written when the EBCOTRateAllocator instance calls encodeTilePartHeader.

See Also:

Encoder, Markers, EBCOTRateAllocator

Field Summary

protected java.io.ByteArrayOutputStream	baos The ByteArrayOutputStream to store header data.
private int	defimgn Nominal range bit of the component defining default values in QCD for main header
private int	deftilenr Nominal range bit of the component defining default values in QCD for tile headers
protected ForwardWT	dwt Reference to the DWT module
protected EncoderSpecs	encSpec The encoder specifications
private boolean	enJJ2KMarkSeg Whether or not to write the JJ2000 COM marker segment
protected java.io.DataOutputStream	hbuf The DataOutputStream to store header data.
protected boolean[]	isOrigSig An array specifying, for each component,if the data was signed or not
private int	nComp The number of components in the image
static char	OPT_PREFIX The prefix for the header encoder options: 'H'
protected ImgData	origSrc The image data reader.
private java.lang.String	otherCOMMarkSeg Other COM marker segments specified in the command line
private static java.lang.String[][]	pinfo The list of parameters that are accepted for the header encoder module.
protected PostCompRateAllocator	ralloc Reference to the rate allocator
protected ROIScaler	roiSc Reference to the ROI module
protected Tiler	tiler Reference to the tiler module

Fields inherited from interface jj2000.j2k.codestream.Markers

COC, COD, COM, CRG, EOC, EPH, EPH_LENGTH, ERS_SEG_SYMBOLS, ERS_SOP, MAX_COMP_BITDEPTH, MAX_LPPM, MAX_LPPT, PLM, PLT, POC, PPM, PPT, PRECINCT_PARTITION_DEF_SIZE, QCC, QCD, RCOM_GEN_USE, RGN, RSIZ_BASELINE, RSIZ_ER_FLAG, RSIZ_ROI, SCOX_HOR_CB_PART, SCOX_PRECINCT_PARTITION, SCOX_USE_EPH, SCOX_USE_SOP, SCOX_VER_CB_PART, SIZ, SOC, SOD, SOP, SOP_LENGTH, SOT, SQCX_EXP_MASK, SQCX_EXP_SHIFT, SQCX_GB_MSK, SQCX_GB_SHIFT, SQCX_NO_QUANTIZATION, SQCX_SCALAR_DERIVED, SQCX_SCALAR_EXPOUNDED, SRGN_IMPLICIT, SSIZ_DEPTH_BITS, TLM

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

HeaderEncoder(ImgData origsrc, boolean[] isorigsig, ForwardWT dwt, Tiler tiler, EncoderSpecs encSpec, ROIScaler roiSc, PostCompRateAllocator ralloc, ParameterList pl)
Initializes the header writer with the references to the coding chain.

Method Summary

void	encodeMainHeader() Write main header.
void	encodeTilePartHeader(int tileLength, int tileIdx) Writes tile-part header.
protected byte[]	getBuffer() Returns the byte-buffer used to store the codestream header.
protected int	getBufferLength() Returns the number of bytes used in the codestream header's buffer.
int	getLength() Returns the length of the header.
static java.lang.String[][]	getParameterInfo() Returns the parameters that are used in this class and implementing classes.
void	reset() Resets the contents of this HeaderEncoder to its initial state.
protected void	writeCOC(boolean mh, int tileIdx, int compIdx) Writes COC marker segment .
protected void	writeCOD(boolean mh, int tileIdx) Writes COD marker segment.
private void	writeCOM() Write COM marker segment(s) to the codestream.
protected void	writeMainQCC(int compIdx) Writes QCC marker segment in main header.
protected void	writeMainQCD() Writes QCD marker segment in main header.
protected void	writePOC(boolean mh, int tileIdx) Writes POC marker segment.
private void	writeRGN(int tIdx) Writes the RGN marker segment in the tile header.
private void	writeSIZ() Writes SIZ marker segment of the codestream header.
private void	writeSOC() Start Of Codestream marker (SOC) signalling the beginning of a codestream.
protected void	writeTileQCC(int t, int compIdx) Writes QCC marker segment in tile header.
protected void	writeTileQCD(int tIdx) Writes QCD marker segment in tile header.
void	writeTo(BinaryDataOutput out) Writes the header to the specified BinaryDataOutput.
void	writeTo(java.io.OutputStream out) Writes the header to the specified OutputStream.

Methods inherited from class java.lang.Object

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

Field Detail

OPT_PREFIX

public static final char OPT_PREFIX

The prefix for the header encoder options: 'H'

See Also:

Constant Field Values

pinfo

private static final java.lang.String[][] pinfo

The list of parameters that are accepted for the header encoder module. Options for this modules start with 'H'.

defimgn

private int defimgn

Nominal range bit of the component defining default values in QCD for main header

deftilenr

private int deftilenr

Nominal range bit of the component defining default values in QCD for tile headers

nComp

private int nComp

The number of components in the image

enJJ2KMarkSeg

private boolean enJJ2KMarkSeg

Whether or not to write the JJ2000 COM marker segment

otherCOMMarkSeg

private java.lang.String otherCOMMarkSeg

Other COM marker segments specified in the command line

baos

protected java.io.ByteArrayOutputStream baos

The ByteArrayOutputStream to store header data. This handler is kept in order to use methods not accessible from a general DataOutputStream. For the other methods, it's better to use variable hbuf.

See Also:

hbuf

hbuf

protected java.io.DataOutputStream hbuf

The DataOutputStream to store header data. This kind of object is useful to write short, int, .... It's constructor takes baos as parameter.

See Also:

baos

origSrc

protected ImgData origSrc

The image data reader. Source of original data info

isOrigSig

protected boolean[] isOrigSig

An array specifying, for each component,if the data was signed or not

ralloc

protected PostCompRateAllocator ralloc

Reference to the rate allocator

dwt

protected ForwardWT dwt

Reference to the DWT module

tiler

protected Tiler tiler

Reference to the tiler module

roiSc

protected ROIScaler roiSc

Reference to the ROI module

encSpec

protected EncoderSpecs encSpec

The encoder specifications

Constructor Detail

HeaderEncoder

public HeaderEncoder(ImgData origsrc,
                     boolean[] isorigsig,
                     ForwardWT dwt,
                     Tiler tiler,
                     EncoderSpecs encSpec,
                     ROIScaler roiSc,
                     PostCompRateAllocator ralloc,
                     ParameterList pl)

Initializes the header writer with the references to the coding chain.

Parameters:

origsrc - The original image data (before any component mixing, tiling, etc.)

isorigsig - An array specifying for each component if it was originally signed or not.

dwt - The discrete wavelet transform module.

tiler - The tiler module.

encSpec - The encoder specifications

roiSc - The ROI scaler module.

ralloc - The post compression rate allocator.

pl - ParameterList instance.

Method Detail

getParameterInfo

public static java.lang.String[][] getParameterInfo()

Returns the parameters that are used in this class and implementing classes. It returns a 2D String array. Each of the 1D arrays is for a different option, and they have 3 elements. The first element is the option name, the second one is the synopsis, the third one is a long description of what the parameter is and the fourth is its default value. The synopsis or description may be 'null', in which case it is assumed that there is no synopsis or description of the option, respectively. Null may be returned if no options are supported.

Returns:

the options name, their synopsis and their explanation, or null if no options are supported.

reset

public void reset()

Resets the contents of this HeaderEncoder to its initial state. It erases all the data in the header buffer and reactualizes the headerLength field of the bit stream writer.

getBuffer

protected byte[] getBuffer()

Returns the byte-buffer used to store the codestream header.

Returns:

A byte array countaining codestream header

getLength

public int getLength()

Returns the length of the header.

Returns:

The length of the header in bytes

writeTo

public void writeTo(BinaryDataOutput out)
             throws java.io.IOException

Writes the header to the specified BinaryDataOutput.

Parameters:

out - Where to write the header.

java.io.IOException

getBufferLength

protected int getBufferLength()

Returns the number of bytes used in the codestream header's buffer.

Returns:

Header length in buffer (without any header overhead)

writeTo

public void writeTo(java.io.OutputStream out)
             throws java.io.IOException

Writes the header to the specified OutputStream.

Parameters:

out - Where to write the header.

java.io.IOException

writeSOC

private void writeSOC()
               throws java.io.IOException

Start Of Codestream marker (SOC) signalling the beginning of a codestream.

java.io.IOException

writeSIZ

private void writeSIZ()
               throws java.io.IOException

Writes SIZ marker segment of the codestream header. It is a fixed information marker segment containing informations about image and tile sizes. It is required in the main header immediately after SOC marker segment.

java.io.IOException

writeCOD

protected void writeCOD(boolean mh,
                        int tileIdx)
                 throws java.io.IOException

Writes COD marker segment. COD is a functional marker segment containing the code style default (coding style, decomposition, layering) used for compressing all the components in an image.

The values can be overriden for an individual component by a COC marker in either the main or the tile header.

Parameters:

mh - Flag indicating whether this marker belongs to the main header

tileIdx - Tile index if the marker belongs to a tile-part header

java.io.IOException

See Also:

writeCOC(boolean, int, int)

writeCOC

protected void writeCOC(boolean mh,
                        int tileIdx,
                        int compIdx)
                 throws java.io.IOException

Writes COC marker segment . It is a functional marker containing the coding style for one component (coding style, decomposition, layering).

Its values overrides any value previously set in COD in the main header or in the tile header.

Parameters:

mh - Flag indicating whether the main header is to be written.

tileIdx - Tile index.

compIdx - index of the component which need use of the COC marker segment.

java.io.IOException

See Also:

writeCOD(boolean, int)

writeMainQCD

protected void writeMainQCD()
                     throws java.io.IOException

Writes QCD marker segment in main header. QCD is a functional marker segment countaining the quantization default used for compressing all the components in an image. The values can be overriden for an individual component by a QCC marker in either the main or the tile header.

java.io.IOException

writeMainQCC

protected void writeMainQCC(int compIdx)
                     throws java.io.IOException

Writes QCC marker segment in main header. It is a functional marker segment countaining the quantization used for compressing the specified component in an image. The values override for the specified component what was defined by a QCC marker in either the main or the tile header.

Parameters:

compIdx - Index of the component which needs QCC marker segment.

java.io.IOException

writeTileQCD

protected void writeTileQCD(int tIdx)
                     throws java.io.IOException

Writes QCD marker segment in tile header. QCD is a functional marker segment countaining the quantization default used for compressing all the components in an image. The values can be overriden for an individual component by a QCC marker in either the main or the tile header.

Parameters:

tIdx - Tile index

java.io.IOException

writeTileQCC

protected void writeTileQCC(int t,
                            int compIdx)
                     throws java.io.IOException

Writes QCC marker segment in tile header. It is a functional marker segment countaining the quantization used for compressing the specified component in an image. The values override for the specified component what was defined by a QCC marker in either the main or the tile header.

Parameters:

t - Tile index

compIdx - Index of the component which needs QCC marker segment.

java.io.IOException

writePOC

protected void writePOC(boolean mh,
                        int tileIdx)
                 throws java.io.IOException

Writes POC marker segment. POC is a functional marker segment containing the bounds and progression order for any progression order other than default in the codestream.

Parameters:

mh - Flag indicating whether the main header is to be written

tileIdx - Tile index

java.io.IOException

encodeMainHeader

public void encodeMainHeader()
                      throws java.io.IOException

Write main header. JJ2000 main header corresponds to the following sequence of marker segments:

1. SOC
2. SIZ
3. COD
4. COC (if needed)
5. QCD
6. QCC (if needed)
7. POC (if needed)

java.io.IOException

writeCOM

private void writeCOM()
               throws java.io.IOException

Write COM marker segment(s) to the codestream.

This marker is currently written in main header and indicates the JJ2000 encoder's version that has created the codestream.

java.io.IOException

writeRGN

private void writeRGN(int tIdx)
               throws java.io.IOException

Writes the RGN marker segment in the tile header. It describes the scaling value in each tile component

May be used in tile or main header. If used in main header, it refers to a ROI of the whole image, regardless of tiling. When used in tile header, only the particular tile is affected.

Parameters:

tIdx - The tile index

Throws:

java.io.IOException - If an I/O error occurs while reading from the encoder header stream

encodeTilePartHeader

public void encodeTilePartHeader(int tileLength,
                                 int tileIdx)
                          throws java.io.IOException

Writes tile-part header. JJ2000 tile-part header corresponds to the following sequence of marker segments:

1. SOT
2. COD (if needed)
3. COC (if needed)
4. QCD (if needed)
5. QCC (if needed)
6. RGN (if needed)
7. POC (if needed)
8. SOD

Parameters:

tileIdx - Index of the tile to write

java.io.IOException