ptolemy.domains.sdf.lib.vq
Class HTVQEncode

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.actor.lib.Transformer
                              ptolemy.domains.sdf.lib.vq.HTVQEncode

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable

public class HTVQEncode
extends Transformer

This actor encodes a matrix using Hierarchical Table-Lookup Vector Quantization. The matrix must be of dimensions that are amenable to this method. (i.e. 2x1, 2x2, 4x2, 4x4, etc.) Instead of performing a full-search vector quantization during execution, all the optimal encoding vectors are calculated before hand and stored in a lookup table. (This is known as Table-lookup Vector Quantization). However, for large vector sizes the lookup tables are unmanageably large. This actor approximates a full search VQ by storing the lookup tables hierarchically. The encoding is broken up into stages, and at each stage a number of 2x1 table lookup VQs are performed. For example, starting with a 4x2 vector in the first stage, codebook 0 (which operates on raw pixels) is used 4 times, resulting in a 2x2 vector of codewords. In the second stage, codebook 1 is used twice, resulting in a 2x1 vector. Lastly, a single 2x1 VQ using codebook 2 (which operates on codewords representing 2x2 vectors) returns a single codeword for the 4x2 vector.

The input is an IntMatrixToken corresponding to the block to be encoded. The values in this matrix are assumed to be between 0 and 255. The output is an IntToken with value between 0 and 255. Integers are used here because of the minimal byte support in Ptolemy or JAVA. The size of the input matrix should be the same as the parameters blockHeight and blockWidth.

The codebook is specified as a binary file that will be read during initialization. This file actually contains five sets of codebooks and lookups tables. The first set is for 2x1 blocks, the second is for 2x2 blocks, etc. (Thus the supplied codebook is only sufficient for block sizes up to 8x4 pixels.) In each set, the codebook precedes the lookup-tables. The codebook consists of all 256 codevectors, row scanned from top to bottom. The lookup table consists of 64K entries (one for each pair of codewords from the previous stage). Each entry in the lookup table is an 8-bit codeword.

 Stage 0: 2x1 block size
 codebook = 256 blocks x 2 bytes = 512 bytes
 lookup tables = 65536 entries x 1 byte = 65536 bytes
 Stage 1: 2x2 block size
 codebook = 256 blocks x 4 bytes = 1024 bytes
 lookup tables = 65536 entries x 1 byte = 65536 bytes
 Stage 2: 4x2 block size
 codebook = 256 blocks x 8 bytes = 2048 bytes
 lookup tables = 65536 entries x 1 byte = 65536 bytes
 Stage 3: 4x4 block size
 codebook = 256 blocks x 16 bytes = 4096 bytes
 lookup tables = 65536 entries x 1 byte = 65536 bytes
 Stage 4: 8x4 block size
 codebook = 256 blocks x 32 bytes = 8192 bytes
 lookup tables = 65536 entries x 1 byte = 65536 bytes
 

The supplied codebook was trained using images from the USC image archive and is suitable for most general applications.
For more information here are some interesting references:
A. Gersho and R. M. Gray, Vector Quantization and Signal Compression. Kluwer Academic Publishers, Boston, 1992.
P. C. Chang, J. May, R. M. Gray, "Hierarchical Vector Quantizers with Table Lookup Encoders," International Conference on Acoustics Speech and Signal Processing, pp. 1452-1455, 1985.
M. Vishwanath and P. Chou, "An Efficient Algorithm for Hierarchical Compression of Video," International Conference on Image Processing, vol. 3, pp. 275-279, Nov. 1994.

Since:

Ptolemy II 0.2

Version:

$Id: HTVQEncode.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Steve Neuendorffer

See Also:

Serialized Form

Accepted Rating:

Red (neuendor)

Proposed Rating:

Yellow (neuendor)

Nested Class Summary

Nested classes/interfaces inherited from class ptolemy.kernel.Entity

Entity.ContainedObjectsIterator

Field Summary

private int	_blockCount
private int	_blockHeight
private Token[]	_blocks
private int	_blockWidth
private int[][][]	_codeBook
private IntToken[]	_codewords
private int[][]	_lookupTable
Parameter	blockCount The number of blocks to be encoded during each firing.
Parameter	blockHeight The width, in pixels, of the block to encode.
Parameter	blockWidth The width, in pixels, of the block to encode.
Parameter	codeBook A Parameter of type String, giving the location of the codebook data file relative to the root classpath.
Parameter	input_tokenConsumptionRate The input rate.
private int[][]	ipbuf_encodep1
private int[][]	ipbuf_encodep2
Parameter	output_tokenProductionRate The output rate.

Fields inherited from class ptolemy.actor.lib.Transformer

input, output

Fields inherited from class ptolemy.actor.AtomicActor

_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS

Fields inherited from interface ptolemy.actor.Executable

COMPLETED, NOT_READY, STOP_ITERATING

Constructor Summary

HTVQEncode(CompositeEntity container, java.lang.String name)
Construct an actor in the specified container with the specified name.

Method Summary

private int	_encode(int[] p, int length)
private int	_fullRead(java.io.InputStream s, byte[] b)
private int	_stages(int length) Given a vector of the given length, compute the codebook stage appropriate.
void	fire() Fire this actor.
void	initialize() Initialize this actor.

Methods inherited from class ptolemy.actor.TypedAtomicActor

_addPort, _fireAt, _fireAt, attributeTypeChanged, clone, newPort, typeConstraintList, typeConstraints

Methods inherited from class ptolemy.actor.AtomicActor

_actorFiring, _actorFiring, addActorFiringListener, addInitializable, clone, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, postfire, prefire, preinitialize, pruneDependencies, recordFiring, removeActorFiringListener, removeDependency, removeInitializable, setContainer, stop, stopFire, terminate, wrapup

Methods inherited from class ptolemy.kernel.ComponentEntity

_adjustDeferrals, _checkContainer, _getContainedObject, _propagateExistence, getContainer, instantiate, isAtomic, isOpaque, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, propagateExistence, setName

Methods inherited from class ptolemy.kernel.Entity

_description, _exportMoMLContents, _removePort, _validateSettables, connectedPortList, connectedPorts, containedObjectsIterator, getAttribute, getPort, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts, setClassDefinition, uniqueName

Methods inherited from class ptolemy.kernel.InstantiableNamedObj

_setParent, exportMoML, getChildren, getElementName, getParent, getPrototypeList, isClassDefinition, isWithinClassDefinition

Methods inherited from class ptolemy.kernel.util.NamedObj

_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _debug, _debug, _debug, _debug, _debug, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _propagateValue, _recordDecoratedAttributes, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, attributeChanged, attributeList, attributeList, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getFullName, getModelErrorHandler, getName, getName, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, propagateValue, propagateValues, removeChangeListener, removeDebugListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, validateSettables, workspace

Methods inherited from class java.lang.Object

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

Methods inherited from interface ptolemy.actor.Actor

createReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, newReceiver, outputPortList

Methods inherited from interface ptolemy.actor.Executable

isFireFunctional, isStrict, iterate, postfire, prefire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, preinitialize, removeInitializable, wrapup

Methods inherited from interface ptolemy.kernel.util.Nameable

description, getContainer, getDisplayName, getFullName, getName, getName, setName

Methods inherited from interface ptolemy.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Field Detail

codeBook

public Parameter codeBook

A Parameter of type String, giving the location of the codebook data file relative to the root classpath.

blockCount

public Parameter blockCount

The number of blocks to be encoded during each firing. The default value is one, which will always work, but using a higher number (such as the number of blocks in a frame) will speed things up.

blockWidth

public Parameter blockWidth

The width, in pixels, of the block to encode.

blockHeight

public Parameter blockHeight

The width, in pixels, of the block to encode.

input_tokenConsumptionRate

public Parameter input_tokenConsumptionRate

The input rate.

output_tokenProductionRate

public Parameter output_tokenProductionRate

The output rate.

ipbuf_encodep1

private int[][] ipbuf_encodep1

ipbuf_encodep2

private int[][] ipbuf_encodep2

_codeBook

private int[][][] _codeBook

_lookupTable

private int[][] _lookupTable

_codewords

private IntToken[] _codewords

_blocks

private Token[] _blocks

_blockCount

private int _blockCount

_blockWidth

private int _blockWidth

_blockHeight

private int _blockHeight

Constructor Detail

HTVQEncode

public HTVQEncode(CompositeEntity container,
                  java.lang.String name)
           throws IllegalActionException,
                  NameDuplicationException

Construct an actor in the specified container with the specified name.

Parameters:

container - The container.

name - The name of this adder within the container.

Throws:

IllegalActionException - If the actor cannot be contained by the proposed container.

NameDuplicationException - If the name coincides with an actor already in the container.

Method Detail

fire

public void fire()
          throws IllegalActionException

Fire this actor. Consume a codeword on the input, and perform Vector Quantization using Hierarchical Table-Lookup Vector Quantization. Send the computed codeword on the output.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If a contained method throws it.

initialize

public void initialize()
                throws IllegalActionException

Initialize this actor. Load the codebooks and lookup tables from the file given by the parameter "codeBook".

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If the parameters do not have legal values, or the codebook file cannot be read.

_encode

private int _encode(int[] p,
                    int length)

_fullRead

private int _fullRead(java.io.InputStream s,
                      byte[] b)
               throws java.io.IOException

Throws:

java.io.IOException

_stages

private int _stages(int length)

Given a vector of the given length, compute the codebook stage appropriate. Basically, compute log base 2 of length, assuming length is a power of 2.