abstract codec class for JPEG decoders. More...

Inheritance diagram for DJCodecDecoder:

Public Member Functions
	DJCodecDecoder ()
	default constructor

virtual	~DJCodecDecoder ()
	destructor

virtual OFCondition	decode (const DcmRepresentationParameter fromRepParam, DcmPixelSequence pixSeq, DcmPolymorphOBOW &uncompressedPixelData, const DcmCodecParameter *cp, const DcmStack &objStack) const
	decompresses the given pixel sequence and stores the result in the given uncompressedPixelData element. More...

virtual OFCondition	decodeFrame (const DcmRepresentationParameter fromParam, DcmPixelSequence fromPixSeq, const DcmCodecParameter cp, DcmItem dataset, Uint32 frameNo, Uint32 &startFragment, void *buffer, Uint32 bufSize, OFString &decompressedColorModel) const
	decompresses a single frame from the given pixel sequence and stores the result in the given buffer. More...

virtual OFCondition	encode (const Uint16 pixelData, const Uint32 length, const DcmRepresentationParameter toRepParam, DcmPixelSequence &pixSeq, const DcmCodecParameter cp, DcmStack &objStack) const
	compresses the given uncompressed DICOM image and stores the result in the given pixSeq element. More...

virtual OFCondition	encode (const E_TransferSyntax fromRepType, const DcmRepresentationParameter fromRepParam, DcmPixelSequence fromPixSeq, const DcmRepresentationParameter toRepParam, DcmPixelSequence &toPixSeq, const DcmCodecParameter *cp, DcmStack &objStack) const
	transcodes (re-compresses) the given compressed DICOM image and stores the result in the given toPixSeq element. More...

virtual OFBool	canChangeCoding (const E_TransferSyntax oldRepType, const E_TransferSyntax newRepType) const
	checks if this codec is able to convert from the given current transfer syntax to the given new transfer syntax More...

virtual OFCondition	determineDecompressedColorModel (const DcmRepresentationParameter fromParam, DcmPixelSequence fromPixSeq, const DcmCodecParameter cp, DcmItem dataset, OFString &decompressedColorModel) const
	determine color model of the decompressed image More...

virtual E_TransferSyntax	supportedTransferSyntax () const =0
	returns the transfer syntax that this particular codec is able to decode. More...

virtual OFBool	isLosslessProcess () const =0
	returns true if the transfer syntax supported by this codec is lossless. More...

Public Member Functions inherited from DcmCodec
	DcmCodec ()
	default constructor

virtual	~DcmCodec ()
	destructor

Private Member Functions
virtual DJDecoder *	createDecoderInstance (const DcmRepresentationParameter toRepParam, const DJCodecParameter cp, Uint8 bitsPerSample, OFBool isYBR) const =0
	creates an instance of the compression library to be used for decoding. More...

Static Private Member Functions
static Uint8	scanJpegDataForBitDepth (const Uint8 *data, const Uint32 fragmentLength)
	scans the given block of JPEG data for a Start of Frame marker and returns the number of bits per pixel stored in the Start of Frame block. More...

static Uint16	readUint16 (const Uint8 *data)
	reads two bytes from the given array of little endian 16-bit values and returns the value as Uint16 in local byte order. More...

static OFCondition	createPlanarConfigurationByte (Uint8 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 8 bits/sample from color-by-pixel to color-by-plane planar configuration. More...

static OFCondition	createPlanarConfigurationWord (Uint16 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 16 bits/sample from color-by-pixel to color-by-plane planar configuration. More...

static OFBool	requiresPlanarConfiguration (const char *sopClassUID, EP_Interpretation photometricInterpretation)
	examines if a given image requires color-by-plane planar configuration depending on SOP Class UID (DICOM IOD) and photometric interpretation. More...

Additional Inherited Members
Static Public Member Functions inherited from DcmCodec
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. More...

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. More...

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) More...

static OFCondition	updateImageType (DcmItem *dataset)
	set first value of Image Type to DERIVED. More...

static OFCondition	insertCodeSequence (DcmItem dataset, const DcmTagKey &tagKey, const char codingSchemeDesignator, const char codeValue, const char codeMeaning)
	insert code sequence into the given dataset More...

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) More...

Detailed Description

abstract codec class for JPEG decoders.

This abstract class contains most of the application logic needed for a dcmdata codec object that implements a JPEG decoder using the DJDecoder interface to the underlying JPEG implementation. This class only supports decompression, it neither implements encoding nor transcoding.

Member Function Documentation

◆ canChangeCoding()

virtual OFBool DJCodecDecoder::canChangeCoding	(	const E_TransferSyntax	oldRepType,
		const E_TransferSyntax	newRepType
	)		const

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.

Implements DcmCodec.

◆ createDecoderInstance()

virtual DJDecoder* DJCodecDecoder::createDecoderInstance	(	const DcmRepresentationParameter *	toRepParam,
		const DJCodecParameter *	cp,
		Uint8	bitsPerSample,
		OFBool	isYBR
	)		const

privatepure virtual

creates an instance of the compression library to be used for decoding.

Parameters

toRepParam	representation parameter passed to decode()
cp	codec parameter passed to decode()
bitsPerSample	bits per sample for the image data
isYBR	flag indicating whether DICOM photometric interpretation is YCbCr

Returns: pointer to newly allocated decoder object

Implemented in DJDecoderExtended, DJDecoderLossless, DJDecoderProgressive, DJDecoderSpectralSelection, DJDecoderP14SV1, and DJDecoderBaseline.

◆ createPlanarConfigurationByte()

static OFCondition DJCodecDecoder::createPlanarConfigurationByte	(	Uint8 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)

staticprivate

converts an RGB or YBR frame with 8 bits/sample from color-by-pixel to color-by-plane planar configuration.

Parameters

imageFrame	pointer to image frame, must contain at least 3columnsrows bytes of pixel data.
columns	columns
rows	rows

Returns: EC_Normal if successful, an error code otherwise

◆ createPlanarConfigurationWord()

static OFCondition DJCodecDecoder::createPlanarConfigurationWord	(	Uint16 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)

staticprivate

converts an RGB or YBR frame with 16 bits/sample from color-by-pixel to color-by-plane planar configuration.

Parameters

imageFrame	pointer to image frame, must contain at least 3columnsrows words of pixel data.
columns	columns
rows	rows

Returns: EC_Normal if successful, an error code otherwise

◆ decode()

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

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.

Implements DcmCodec.

◆ decodeFrame()

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

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.

Implements DcmCodec.

◆ determineDecompressedColorModel()

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

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

Implements DcmCodec.

◆ encode() [1/2]

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

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.

Implements DcmCodec.

◆ encode() [2/2]

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

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.

Implements DcmCodec.

◆ isLosslessProcess()

virtual OFBool DJCodecDecoder::isLosslessProcess ( ) const

pure virtual

returns true if the transfer syntax supported by this codec is lossless.

Returns: lossless flag

Implemented in DJDecoderExtended, DJDecoderLossless, DJDecoderProgressive, DJDecoderSpectralSelection, DJDecoderP14SV1, and DJDecoderBaseline.

◆ readUint16()

static Uint16 DJCodecDecoder::readUint16 ( const Uint8 * data )

staticprivate

reads two bytes from the given array of little endian 16-bit values and returns the value as Uint16 in local byte order.

Parameters

data	pointer to array, must not be NULL, must at least 2 bytes large

Returns: Uint16 read from array

◆ requiresPlanarConfiguration()

static OFBool DJCodecDecoder::requiresPlanarConfiguration	(	const char *	sopClassUID,
		EP_Interpretation	photometricInterpretation
	)

staticprivate

examines if a given image requires color-by-plane planar configuration depending on SOP Class UID (DICOM IOD) and photometric interpretation.

All SOP classes defined in the 2003 edition of the DICOM standard or earlier are handled correctly.

Parameters

sopClassUID	SOP Class UID
photometricInterpretation	decompressed photometric interpretation

Returns: true if color-by-plane is required, false otherwise.

◆ scanJpegDataForBitDepth()

static Uint8 DJCodecDecoder::scanJpegDataForBitDepth	(	const Uint8 *	data,
		const Uint32	fragmentLength
	)

staticprivate

scans the given block of JPEG data for a Start of Frame marker and returns the number of bits per pixel stored in the Start of Frame block.

Parameters

data	pointer to array, must not be NULL
fragmentLength	size of array

Returns: bit depth of JPEG data, 0 if no SOF marker found or parse error

◆ supportedTransferSyntax()

virtual E_TransferSyntax DJCodecDecoder::supportedTransferSyntax ( ) const

pure virtual

returns the transfer syntax that this particular codec is able to decode.

Returns: supported transfer syntax

Implemented in DJDecoderExtended, DJDecoderLossless, DJDecoderProgressive, DJDecoderSpectralSelection, DJDecoderP14SV1, and DJDecoderBaseline.

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

dcmjpeg/include/dcmtk/dcmjpeg/djcodecd.h

Public Member Functions

Private Member Functions

Static Private Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ canChangeCoding()

◆ createDecoderInstance()

◆ createPlanarConfigurationByte()

◆ createPlanarConfigurationWord()

◆ decode()

◆ decodeFrame()

◆ determineDecompressedColorModel()

◆ encode() [1/2]

◆ encode() [2/2]

◆ isLosslessProcess()

◆ readUint16()

◆ requiresPlanarConfiguration()

◆ scanJpegDataForBitDepth()

◆ supportedTransferSyntax()