jj2000.j2k.entropy.encoder
Class PostCompRateAllocator

java.lang.Object
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  +--jj2000.j2k.image.ImgDataAdapter
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        +--jj2000.j2k.entropy.encoder.PostCompRateAllocator

All Implemented Interfaces:

ImgData

Direct Known Subclasses:

EBCOTRateAllocator

public abstract class PostCompRateAllocator

extends ImgDataAdapter

This is the abstract class from which post-compression rate allocators which generate layers should inherit. The source of data is a 'CodedCBlkDataSrcEnc' which delivers entropy coded blocks with rate-distortion statistics.

The post compression rate allocator implementation should create the layers, according to a rate allocation policy, and send the packets to a CodestreamWriter. Since the rate allocator sends the packets to the bit stream then it should output the packets to the bit stream in the order imposed by the bit stream profiles.

See Also:

CodedCBlkDataSrcEnc, CodestreamWriter

Field Summary

(package private) CodestreamWriter	bsWriter The bit-stream writer
protected EncoderSpecs	encSpec The source of entropy coded data
(package private) HeaderEncoder	headEnc The header encoder
protected int	numLayers The number of layers.
static char	OPT_PREFIX The prefix for rate allocation options: 'A'
private static java.lang.String[][]	pinfo The list of parameters that is accepted for entropy coding.
protected CodedCBlkDataSrcEnc	src The source of entropy coded data

Fields inherited from class jj2000.j2k.image.ImgDataAdapter

imgdatasrc, tIdx

Constructor Summary

PostCompRateAllocator(CodedCBlkDataSrcEnc src, int nl, CodestreamWriter bw, EncoderSpecs encSpec)
Initializes the source of entropy coded data.

Method Summary

static PostCompRateAllocator	createInstance(CodedCBlkDataSrcEnc src, ParameterList pl, float rate, CodestreamWriter bw, EncoderSpecs encSpec) Creates a PostCompRateAllocator object for the appropriate rate allocation parameters in the parameter list 'pl', having 'src' as the source of entropy coded data, 'rate' as the target bitrate and 'bw' as the bit stream writer object.
int	getNumLayers() Returns the number of layers that are actually generated.
static java.lang.String[][]	getParameterInfo() Returns the parameters that are used in this class and implementing classes.
abstract void	initialize() Initializes the rate allocation points, taking into account header overhead and such.
private static LayersInfo	parseAlayers(java.lang.String params, float rate) Convenience method that parses the 'Alayers' option.
abstract void	runAndWrite() Runs the rate allocation algorithm and writes the data to the bit stream.
void	setHeaderEncoder(HeaderEncoder headEnc) Keep a reference to the header encoder.

Methods inherited from class jj2000.j2k.image.ImgDataAdapter

getCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getCompULX, getCompULY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomRangeBits, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidth, nextTile, setTile

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 rate allocation options: 'A'

See Also:

Constant Field Values

pinfo

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

The list of parameters that is accepted for entropy coding. Options for entropy coding start with 'R'.

src

protected CodedCBlkDataSrcEnc src

The source of entropy coded data

encSpec

protected EncoderSpecs encSpec

The source of entropy coded data

numLayers

protected int numLayers

The number of layers.

bsWriter

CodestreamWriter bsWriter

The bit-stream writer

headEnc

HeaderEncoder headEnc

The header encoder

Constructor Detail

PostCompRateAllocator

public PostCompRateAllocator(CodedCBlkDataSrcEnc src,
                             int nl,
                             CodestreamWriter bw,
                             EncoderSpecs encSpec)

Initializes the source of entropy coded data.

Parameters:

src - The source of entropy coded data.

bw - The packet bit stream writer.

See Also:

ProgressionType

Method Detail

setHeaderEncoder

public void setHeaderEncoder(HeaderEncoder headEnc)

Keep a reference to the header encoder.

Parameters:

headEnc - The header encoder

initialize

public abstract void initialize()
                         throws java.io.IOException

Initializes the rate allocation points, taking into account header overhead and such. This method must be called after the header has been simulated but before calling the runAndWrite() one. The header must be rewritten after a call to this method since the number of layers may change.

java.io.IOException

See Also:

runAndWrite()

runAndWrite

public abstract void runAndWrite()
                          throws java.io.IOException

Runs the rate allocation algorithm and writes the data to the bit stream. This must be called after the initialize() method.

java.io.IOException

See Also:

initialize()

getNumLayers

public int getNumLayers()

Returns the number of layers that are actually generated.

Returns:

The number of layers generated.

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.

createInstance

public static PostCompRateAllocator createInstance(CodedCBlkDataSrcEnc src,
                                                   ParameterList pl,
                                                   float rate,
                                                   CodestreamWriter bw,
                                                   EncoderSpecs encSpec)

Creates a PostCompRateAllocator object for the appropriate rate allocation parameters in the parameter list 'pl', having 'src' as the source of entropy coded data, 'rate' as the target bitrate and 'bw' as the bit stream writer object.

Parameters:

src - The source of entropy coded data.

pl - The parameter lis (or options).

rate - The target bitrate for the rate allocation

bw - The bit stream writer object, where the bit stream data will be written.

parseAlayers

private static LayersInfo parseAlayers(java.lang.String params,
                                       float rate)

Convenience method that parses the 'Alayers' option.

Parameters:

params - The parameters of the 'Alayers' option

rate - The overall target bitrate

Returns:

The layer specification.