DcmCodec Class Reference

abstract base class for a codec object that can be registered in dcmdata and performs transfer syntax transformation (i.e. More...

Inheritance diagram for DcmCodec:

List of all members.

Public Member Functions
	DcmCodec ()
	default constructor
virtual	~DcmCodec ()
	destructor
virtual OFCondition	decode (const DcmRepresentationParameter *fromRepParam, DcmPixelSequence *pixSeq, DcmPolymorphOBOW &uncompressedPixelData, const DcmCodecParameter *cp, const DcmStack &objStack) const =0
	decompresses the given pixel sequence and stores the result in the given uncompressedPixelData element.
virtual OFCondition	decodeFrame (const DcmRepresentationParameter *fromParam, DcmPixelSequence *fromPixSeq, const DcmCodecParameter *cp, DcmItem *dataset, Uint32 frameNo, Uint32 &startFragment, void *buffer, Uint32 bufSize, OFString &decompressedColorModel) const =0
	decompresses a single frame from the given pixel sequence and stores the result in the given buffer.
virtual OFCondition	encode (const Uint16 *pixelData, const Uint32 length, const DcmRepresentationParameter *toRepParam, DcmPixelSequence *&pixSeq, const DcmCodecParameter *cp, DcmStack &objStack) const =0
	compresses the given uncompressed DICOM image and stores the result in the given pixSeq element.
virtual OFCondition	encode (const E_TransferSyntax fromRepType, const DcmRepresentationParameter *fromRepParam, DcmPixelSequence *fromPixSeq, const DcmRepresentationParameter *toRepParam, DcmPixelSequence *&toPixSeq, const DcmCodecParameter *cp, DcmStack &objStack) const =0
	transcodes (re-compresses) the given compressed DICOM image and stores the result in the given toPixSeq element.
virtual OFBool	canChangeCoding (const E_TransferSyntax oldRepType, const E_TransferSyntax newRepType) const =0
	checks if this codec is able to convert from the given current transfer syntax to the given new transfer syntax
virtual OFCondition	determineDecompressedColorModel (const DcmRepresentationParameter *fromParam, DcmPixelSequence *fromPixSeq, const DcmCodecParameter *cp, DcmItem *dataset, OFString &decompressedColorModel) const =0
	determine color model of the decompressed image
Static Public Member Functions
static OFCondition	insertStringIfMissing (DcmItem *dataset, const DcmTagKey &tag, const char *val)
	helper function that inserts a string attribute with a given value into a dataset if missing in the dataset.
static OFCondition	convertToSecondaryCapture (DcmItem *dataset)
	helper function that converts a dataset containing a DICOM image into a valid (standard extended) Secondary Capture object by inserting all attributes that are type 1/2 in Secondary Capture and missing in the source dataset.
static OFCondition	newInstance (DcmItem *dataset, const char *purposeOfReferenceCodingScheme=NULL, const char *purposeOfReferenceCodeValue=NULL, const char *purposeOfReferenceCodeMeaning=NULL)
	create new SOP instance UID and Source Image Sequence referencing the old SOP instance (if present)
static OFCondition	updateImageType (DcmItem *dataset)
	set first value of Image Type to DERIVED.
static OFCondition	insertCodeSequence (DcmItem *dataset, const DcmTagKey &tagKey, const char *codingSchemeDesignator, const char *codeValue, const char *codeMeaning)
	insert code sequence into the given dataset
static OFCondition	determineStartFragment (Uint32 frameNo, Sint32 numberOfFrames, DcmPixelSequence *fromPixSeq, Uint32 &currentItem)
	determine the index number (starting with zero) of the compressed pixel data fragment corresponding to the given frame (also starting with zero)

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Detailed Description

abstract base class for a codec object that can be registered in dcmdata and performs transfer syntax transformation (i.e.

compressing, decompressing or transcoding between different compressed transfer syntaxes). When dcmdata is requested to write a transfer syntax that differs from the current one (i.e. the one in which the object was read), dcmdata dynamically searches for a DcmCodec object that is able to create the desired transfer syntax. If no suitable codec is found, the write operation fails.

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Member Function Documentation

virtual OFBool DcmCodec::canChangeCoding	(	const E_TransferSyntax	oldRepType,
		const E_TransferSyntax	newRepType
	)		const [pure virtual]

checks if this codec is able to convert from the given current transfer syntax to the given new transfer syntax

Parameters:

oldRepType	current transfer syntax
newRepType	desired new transfer syntax

Returns:

true if transformation is supported by this codec, false otherwise.

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

static OFCondition DcmCodec::convertToSecondaryCapture

(

DcmItem *

dataset

)

[static]

helper function that converts a dataset containing a DICOM image into a valid (standard extended) Secondary Capture object by inserting all attributes that are type 1/2 in Secondary Capture and missing in the source dataset.

Replaces SOP Class UID by Secondary Capture. It does not, however, change an existing SOP Instance UID.

Parameters:

dataset

dataset to insert to, must not be NULL.

Returns:

EC_Normal if successful, an error code otherwise

virtual OFCondition DcmCodec::decode	(	const DcmRepresentationParameter *	fromRepParam,
		DcmPixelSequence *	pixSeq,
		DcmPolymorphOBOW &	uncompressedPixelData,
		const DcmCodecParameter *	cp,
		const DcmStack &	objStack
	)		const [pure virtual]

decompresses the given pixel sequence and stores the result in the given uncompressedPixelData element.

Parameters:

fromRepParam	current representation parameter of compressed data, may be NULL
pixSeq	compressed pixel sequence
uncompressedPixelData	uncompressed pixel data stored in this element
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

virtual OFCondition DcmCodec::decodeFrame	(	const DcmRepresentationParameter *	fromParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmCodecParameter *	cp,
		DcmItem *	dataset,
		Uint32	frameNo,
		Uint32 &	startFragment,
		void *	buffer,
		Uint32	bufSize,
		OFString &	decompressedColorModel
	)		const [pure virtual]

decompresses a single frame from the given pixel sequence and stores the result in the given buffer.

Parameters:

fromParam	representation parameter of current compressed representation, may be NULL.
fromPixSeq	compressed pixel sequence
cp	codec parameters for this codec
dataset	pointer to dataset in which pixel data element is contained
frameNo	number of frame, starting with 0 for the first frame
startFragment	index of the compressed fragment that contains all or the first part of the compressed bitstream for the given frameNo. Upon successful return this parameter is updated to contain the index of the first compressed fragment of the next frame. When unknown, zero should be passed. In this case the decompression algorithm will try to determine the index by itself, which will always work if frames are decompressed in increasing order from first to last, but may fail if frames are decompressed in random order, multiple fragments per frame and multiple frames are present in the dataset, and the offset table is empty.
buffer	pointer to buffer where frame is to be stored
bufSize	size of buffer in bytes
decompressedColorModel	upon successful return, the color model of the decompressed image (which may be different from the one used in the compressed images) is returned in this parameter.

Returns:

EC_Normal if successful, an error code otherwise.

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

virtual OFCondition DcmCodec::determineDecompressedColorModel	(	const DcmRepresentationParameter *	fromParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmCodecParameter *	cp,
		DcmItem *	dataset,
		OFString &	decompressedColorModel
	)		const [pure virtual]

determine color model of the decompressed image

Parameters:

fromParam	representation parameter of current compressed representation, may be NULL
fromPixSeq	compressed pixel sequence
cp	codec parameters for this codec
dataset	pointer to dataset in which pixel data element is contained
dataset	pointer to DICOM dataset in which this pixel data object is located. Used to access photometric interpretation.
decompressedColorModel	upon successful return, the color model of the decompressed image (which may be different from the one used in the compressed images) is returned in this parameter

Returns:

EC_Normal if successful, an error code otherwise

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

static OFCondition DcmCodec::determineStartFragment	(	Uint32	frameNo,
		Sint32	numberOfFrames,
		DcmPixelSequence *	fromPixSeq,
		Uint32 &	currentItem
	)		[static]

determine the index number (starting with zero) of the compressed pixel data fragment corresponding to the given frame (also starting with zero)

Parameters:

frameNo	frame number
numberOfFrames	number of frames of this image
fromPixSeq	compressed pixel sequence
currentItem	index of compressed pixel data fragment returned in this parameter on success

Returns:

EC_Normal if successful, an error code otherwise

virtual OFCondition DcmCodec::encode	(	const Uint16 *	pixelData,
		const Uint32	length,
		const DcmRepresentationParameter *	toRepParam,
		DcmPixelSequence *&	pixSeq,
		const DcmCodecParameter *	cp,
		DcmStack &	objStack
	)		const [pure virtual]

compresses the given uncompressed DICOM image and stores the result in the given pixSeq element.

Parameters:

pixelData	pointer to the uncompressed image data in OW format and local byte order
length	of the pixel data field in bytes
toRepParam	representation parameter describing the desired compressed representation (e.g. JPEG quality)
pixSeq	compressed pixel sequence (pointer to new DcmPixelSequence object allocated on heap) returned in this parameter upon success.
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

virtual OFCondition DcmCodec::encode	(	const E_TransferSyntax	fromRepType,
		const DcmRepresentationParameter *	fromRepParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmRepresentationParameter *	toRepParam,
		DcmPixelSequence *&	toPixSeq,
		const DcmCodecParameter *	cp,
		DcmStack &	objStack
	)		const [pure virtual]

transcodes (re-compresses) the given compressed DICOM image and stores the result in the given toPixSeq element.

Parameters:

fromRepType	current transfer syntax of the compressed image
fromRepParam	current representation parameter of compressed data, may be NULL
fromPixSeq	compressed pixel sequence
toRepParam	representation parameter describing the desired new compressed representation (e.g. JPEG quality)
toPixSeq	compressed pixel sequence (pointer to new DcmPixelSequence object allocated on heap) returned in this parameter upon success.
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implemented in DJCodecEncoder, DJCodecDecoder, DJLSEncoderBase, DJLSDecoderBase, DcmRLECodecEncoder, and DcmRLECodecDecoder.

static OFCondition DcmCodec::insertCodeSequence	(	DcmItem *	dataset,
		const DcmTagKey &	tagKey,
		const char *	codingSchemeDesignator,
		const char *	codeValue,
		const char *	codeMeaning
	)		[static]

insert code sequence into the given dataset

Parameters:

dataset	dataset to insert into
tagKey	tag of the code sequence
codingSchemeDesignator	coding scheme designator for the sequence item
codeValue	code value for the sequence item
codeMeaning	code meaning for the sequence item

Returns:

EC_Normal if successul, an error code otherwise

static OFCondition DcmCodec::insertStringIfMissing	(	DcmItem *	dataset,
		const DcmTagKey &	tag,
		const char *	val
	)		[static]

helper function that inserts a string attribute with a given value into a dataset if missing in the dataset.

Parameters:

dataset	dataset to insert to, must not be NULL.
tag	tag key of attribute to check/insert
val	string value, may be NULL.

Returns:

EC_Normal if successful, an error code otherwise

static OFCondition DcmCodec::newInstance	(	DcmItem *	dataset,
		const char *	purposeOfReferenceCodingScheme = NULL,
		const char *	purposeOfReferenceCodeValue = NULL,
		const char *	purposeOfReferenceCodeMeaning = NULL
	)		[static]

create new SOP instance UID and Source Image Sequence referencing the old SOP instance (if present)

Parameters:

dataset	dataset to be modified
purposeOfReferenceCodingScheme	coding scheme designator for purpose of reference code sequence
purposeOfReferenceCodeValue	code value for purpose of reference code sequence
purposeOfReferenceCodeMeaning	code meaning for purpose of reference code sequence

Returns:

EC_Normal if successful, an error code otherwise

static OFCondition DcmCodec::updateImageType

(

DcmItem *

dataset

)

[static]

set first value of Image Type to DERIVED.

Parameters:

dataset

dataset to be modified

Returns:

EC_Normal if successful, an error code otherwise

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

• dcmdata/include/dcmtk/dcmdata/dccodec.h