SoJp3dDataCompressor Class Reference
[Compressor]

JP3D data compression More...

#include <LDM/compressors/SoJp3dDataCompressor.h>

Inheritance diagram for SoJp3dDataCompressor:

List of all members.

Public Member Functions
	SoJp3dDataCompressor ()
virtual	~SoJp3dDataCompressor ()
virtual SbString	getCompressionFormatName () const
virtual bool	isLossless ()
virtual size_t	compress (void *src, size_t srcLen, const TileInfo &tileInfo)
virtual size_t	uncompress (void *dst, size_t dstLen, const TileInfo &tileInfo)

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Detailed Description

JP3D data compression

This class implements a wavelet compression scheme based on JP3D compression, an extension of the standard JPEG2000 algorithms specifically designed for volume data. It supports lossless and lossy compression. This is controlled by setCompressionLevel (see SoDataCompressor or SoConvertedParameters). A compression level of 0 specifies the lossless mode. Any other value specifies the target PSNR (Peak Signal to Noise Ratio).

Typical values for compression level (PSNR):

• 0 specifies lossless mode.

• 70 stands for "near lossless" mode (~0.03% error). Most of the volume will be encoded losslessly, but some parts will be encoded with a little error.

• 40 is the "visually lossless" mode (~1% error). Some error will be introduced, but visually the volume will appear the same.

Limitations:

• The maximum precision supported is 16 bits.
  Data values larger than 16 bits, for example float or 32 bit integer, will be converted to 16 bit integers, potentially making the compression lossy.

SEE ALSO

SoGzipDataCompressor, SoJpegDataCompressor, SoDataCompressor, SoConverterParameters

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Constructor & Destructor Documentation

SoJp3dDataCompressor::SoJp3dDataCompressor

(

)

Constructor.

virtual SoJp3dDataCompressor::~SoJp3dDataCompressor

(

)

[virtual]

Destructor.

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Member Function Documentation

virtual size_t SoJp3dDataCompressor::compress	(	void *	src,
		size_t	srcLen,
		const TileInfo &	tileInfo
	)			[virtual]

Compresses the given buffer into the internal buffer.

Parameters:

	src	a pointer to the data to compress.
	srcLen	the size of the source buffer in bytes.
	tileInfo	contains information about the tile being processed.

Returns:

The size in bytes of the compressed buffer.

Implements SoDataCompressor.

virtual SbString SoJp3dDataCompressor::getCompressionFormatName

(

)

const [virtual]

Returns the name of the compression algorithm used by this class.

This is the name the user must pass to the "-c" option of the converter to use this compression ("jp3d" here).

Returns:

An SbString containing "jp3d".

Implements SoDataCompressor.

virtual bool SoJp3dDataCompressor::isLossless

(

)

[virtual]

Checks if the compression is lossless.

The lossless mode is active if the compression level is 0 (the default).

Implements SoDataCompressor.

virtual size_t SoJp3dDataCompressor::uncompress	(	void *	dst,
		size_t	dstLen,
		const TileInfo &	tileInfo
	)			[virtual]

Uncompresses data from the internal buffer to the given buffer.

Parameters:

	dst	a pointer to the destination buffer.
	dstLen	the size of the destination buffer.
	tileInfo	contains information about the tile being processed

Returns:

The number of uncompressed bytes.

Implements SoDataCompressor.

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The documentation for this class was generated from the following file:

• LDM/compressors/SoJp3dDataCompressor.h