Class StdEntropyCoder
- All Implemented Interfaces:
CodedCBlkDataSrcEnc,StdEntropyCoderOptions,ImgData,ForwWTDataProps
The number of threads used by this entropy coder is specified by the "jj2000.j2k.entropy.encoder.StdEntropyCoder.nthreads" Java system property. If set to "0" the single threaded implementation is used. If set to 'n' ('n' larger than 0) then 'n' extra threads are started by this class which are used to encode the code-blocks in parallel (i.e. ideally 'n' code-blocks will be encoded in parallel at a time). On multiprocessor machines under a "native threads" Java Virtual Machine implementation each one of these threads can run on a separate processor speeding up the encoding time. By default the single-threaded implementation is used. The multi-threaded implementation currently assumes that the vast majority of consecutive calls to 'getNextCodeBlock()' will be done on the same component. If this is not the case, the speed-up that can be expected on multiprocessor machines might be significantly decreased.
The code-blocks are rectangular, with dimensions which must be powers of 2. Each dimension has to be no smaller than 4 and no larger than 256. The product of the two dimensions (i.e. area of the code-block) may not exceed 4096.
Context 0 of the MQ-coder is used as the uniform one (uniform, non-adaptive probability distribution). Context 1 is used for RLC coding. Contexts 2-10 are used for zero-coding (ZC), contexts 11-15 are used for sign-coding (SC) and contexts 16-18 are used for magnitude-refinement (MR).
This implementation buffers the symbols and calls the MQ coder only once per stripe and per coding pass, to reduce the method call overhead.
This implementation also provides some timing features. They can be enabled by setting the 'DO_TIMING' constant of this class to true and recompiling. The timing uses the 'System.currentTimeMillis()' Java API call, which returns wall clock time, not the actual CPU time used. The timing results will be printed on the message output. Since the times reported are wall clock times and not CPU usage times they can not be added to find the total used time (i.e. some time might be counted in several places). When timing is disabled ('DO_TIMING' is false) there is no penalty if the compiler performs some basic optimizations. Even if not the penalty should be negligeable.
The source module must implement the CBlkQuantDataSrcEnc interface and code-block's data is received in a CBlkWTData instance. This modules sends code-block's information in a CBlkRateDistStats instance.
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Field Summary
FieldsModifier and TypeFieldDescriptionBy-pass mode specificationsCausal stripes specificationsstatic final StringThe default value for the property in THREADS_PROP_NAME: 0The length calculation specificationsMQ reset specificationsRegular termination specificationsError resilience segment symbol use specificationsstatic final intThe increase in priority for the compressor threads, currently 3.static final StringThe Java system property name for the number of threads to use: jj2000.j2k.entropy.encoder.StdEntropyCoder.nthreadsThe termination type specificationsFields inherited from class jj2000.j2k.entropy.encoder.EntropyCoder
OPT_PREFIX, srcFields inherited from class jj2000.j2k.image.ImgDataAdapter
imgdatasrc, tIdxFields 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
ConstructorsConstructorDescriptionStdEntropyCoder(CBlkQuantDataSrcEnc src, CBlkSizeSpec cblks, PrecinctSizeSpec pss, StringSpec bms, StringSpec mqrs, StringSpec rts, StringSpec css, StringSpec sss, StringSpec lcs, StringSpec tts) Instantiates a new entropy coder engine, with the specified source of data, nominal block width and height. -
Method Summary
Modifier and TypeMethodDescriptionvoidfinalize()Prints the timing information, if collected, and calls 'finalize' on the super class.intgetCBlkHeight(int t, int c) Returns the code-block height for the specified tile and component.intgetCBlkWidth(int t, int c) Returns the code-block width for the specified tile and component.getNextCodeBlock(int c, CBlkRateDistStats ccb) Returns the next coded code-block in the current tile for the specified component, as a copy (see below).intgetPPX(int t, int c, int rl) Returns the precinct partition width for the specified component, tile and resolution level.intgetPPY(int t, int c, int rl) Returns the precinct partition height for the specified component, tile and resolution level.voidinitTileComp(int nt, int nc) Load options, length calculation type and termination type for each tile-component.voidnextTile()Advances to the next tile, in standard scan-line order (by rows then columns).booleanprecinctPartitionUsed(int c, int t) Returns true if precinct partition is used for the specified component and tile, returns false otherwise.voidsetTile(int x, int y) Changes the current tile, given the new indexes.Methods inherited from class jj2000.j2k.entropy.encoder.EntropyCoder
createInstance, getAnSubbandTree, getCbULX, getCbULY, getParameterInfo, isReversibleMethods 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, getTileWidthMethods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface jj2000.j2k.image.ImgData
getCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getCompULX, getCompULY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomRangeBits, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidth
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Field Details
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THREADS_PROP_NAME
The Java system property name for the number of threads to use: jj2000.j2k.entropy.encoder.StdEntropyCoder.nthreads- See Also:
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DEF_THREADS_NUM
The default value for the property in THREADS_PROP_NAME: 0- See Also:
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THREADS_PRIORITY_INC
public static final int THREADS_PRIORITY_INCThe increase in priority for the compressor threads, currently 3. The compressor threads will have a priority of THREADS_PRIORITY_INC more than the priority of the thread calling this class constructor. Used only in the multi-threaded implementation.- See Also:
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bms
By-pass mode specifications -
mqrs
MQ reset specifications -
rts
Regular termination specifications -
css
Causal stripes specifications -
sss
Error resilience segment symbol use specifications -
lcs
The length calculation specifications -
tts
The termination type specifications
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Constructor Details
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StdEntropyCoder
public StdEntropyCoder(CBlkQuantDataSrcEnc src, CBlkSizeSpec cblks, PrecinctSizeSpec pss, StringSpec bms, StringSpec mqrs, StringSpec rts, StringSpec css, StringSpec sss, StringSpec lcs, StringSpec tts) Instantiates a new entropy coder engine, with the specified source of data, nominal block width and height.If the 'OPT_PRED_TERM' option is given then the MQ termination must be 'TERM_PRED_ER' or an exception is thrown.
- Parameters:
src- The source of datacblks- Code-block size specificationspss- Precinct partition specificationsbms- By-pass mode specificationsmqrs- MQ-reset specificationsrts- Regular termination specificationscss- Causal stripes specificationssss- Error resolution segment symbol use specificationslcs- Length computation specificationstts- Termination type specifications- See Also:
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Method Details
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finalize
Prints the timing information, if collected, and calls 'finalize' on the super class. -
getCBlkWidth
public int getCBlkWidth(int t, int c) Returns the code-block width for the specified tile and component.- Specified by:
getCBlkWidthin classEntropyCoder- Parameters:
t- The tile indexc- the component index- Returns:
- The code-block width for the specified tile and component
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getCBlkHeight
public int getCBlkHeight(int t, int c) Returns the code-block height for the specified tile and component.- Specified by:
getCBlkHeightin classEntropyCoder- Parameters:
t- The tile indexc- The component index- Returns:
- The code-block height for the specified tile and component.
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getNextCodeBlock
Returns the next coded code-block in the current tile for the specified component, as a copy (see below). The order in which code-blocks are returned is not specified. However each code-block is returned only once and all code-blocks will be returned if the method is called 'N' times, where 'N' is the number of code-blocks in the tile. After all the code-blocks have been returned for the current tile calls to this method will return 'null'.When changing the current tile (through 'setTile()' or 'nextTile()') this method will always return the first code-block, as if this method was never called before for the new current tile.
The data returned by this method is always a copy of the internal data of this object, if any, and it can be modified "in place" without any problems after being returned.
- Specified by:
getNextCodeBlockin interfaceCodedCBlkDataSrcEnc- Parameters:
c- The component for which to return the next code-block.ccb- If non-null this object might be used in returning the coded code-block in this or any subsequent call to this method. If null a new one is created and returned. If the 'data' array of 'cbb' is not null it may be reused to return the compressed data.- Returns:
- The next coded code-block in the current tile for component 'n', or null if all code-blocks for the current tile have been returned.
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setTile
public void setTile(int x, int y) Changes the current tile, given the new indexes. An IllegalArgumentException is thrown if the indexes do not correspond to a valid tile.This default implementation just changes the tile in the source.
- Specified by:
setTilein interfaceImgData- Overrides:
setTilein classImgDataAdapter- Parameters:
x- The horizontal index of the tile.y- The vertical index of the new tile.
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nextTile
public void nextTile()Advances to the next tile, in standard scan-line order (by rows then columns). An NoNextElementException is thrown if the current tile is the last one (i.e. there is no next tile).This default implementation just advances to the next tile in the source.
- Specified by:
nextTilein interfaceImgData- Overrides:
nextTilein classImgDataAdapter
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initTileComp
public void initTileComp(int nt, int nc) Load options, length calculation type and termination type for each tile-component.- Parameters:
nt- The number of tilesnc- The number of components
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getPPX
public int getPPX(int t, int c, int rl) Returns the precinct partition width for the specified component, tile and resolution level.- Specified by:
getPPXin interfaceCodedCBlkDataSrcEnc- Parameters:
t- the tile indexc- the componentrl- the resolution level- Returns:
- The precinct partition width for the specified component, tile and resolution level
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getPPY
public int getPPY(int t, int c, int rl) Returns the precinct partition height for the specified component, tile and resolution level.- Specified by:
getPPYin interfaceCodedCBlkDataSrcEnc- Parameters:
t- the tile indexc- the componentrl- the resolution level- Returns:
- The precinct partition height for the specified component, tile and resolution level
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precinctPartitionUsed
public boolean precinctPartitionUsed(int c, int t) Returns true if precinct partition is used for the specified component and tile, returns false otherwise.- Specified by:
precinctPartitionUsedin interfaceCodedCBlkDataSrcEnc- Parameters:
c- The componentt- The tile- Returns:
- True if precinct partition is used for the specified component and tile, returns false otherwise.
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