Compression

Image compression primitives. More...

Modules
	Quantization Functions

Data Structures
struct	NppiJpegFrameDescr
	JPEG frame descriptor. More...
struct	NppiJpegScanDescr
	JPEG scan descriptor. More...
struct	NppiJpegDecodeJob
	JPEG decode job used by nppiJpegDecodeJob (see that for more documentation) More...
struct	NppiJpegDecodeJobMemory
	Memory buffers used by one decode job. More...

Typedefs
typedef struct NppiDecodeHuffmanSpec	NppiDecodeHuffmanSpec
typedef struct NppiEncodeHuffmanSpec	NppiEncodeHuffmanSpec

Functions
NppStatus	nppiDecodeHuffmanSpecGetBufSize_JPEG (int *pSize)
	Returns the length of the NppiDecodeHuffmanSpec structure. More...
NppStatus	nppiDecodeHuffmanSpecInitHost_JPEG (const Npp8u *pRawHuffmanTable, NppiHuffmanTableType eTableType, NppiDecodeHuffmanSpec *pHuffmanSpec)
	Creates a Huffman table in a format that is suitable for the decoder on the host. More...
NppStatus	nppiDecodeHuffmanSpecInitAllocHost_JPEG (const Npp8u *pRawHuffmanTable, NppiHuffmanTableType eTableType, NppiDecodeHuffmanSpec **ppHuffmanSpec)
	Allocates memory and creates a Huffman table in a format that is suitable for the decoder on the host. More...
NppStatus	nppiDecodeHuffmanSpecFreeHost_JPEG (NppiDecodeHuffmanSpec *pHuffmanSpec)
	Frees the host memory allocated by nppiDecodeHuffmanSpecInitAllocHost_JPEG. More...
NppStatus	nppiDecodeHuffmanScanHost_JPEG_8u16s_P1R (const Npp8u *pSrc, Npp32s nLength, Npp32s restartInterval, Npp32s Ss, Npp32s Se, Npp32s Ah, Npp32s Al, Npp16s *pDst, Npp32s nDstStep, NppiDecodeHuffmanSpec *pHuffmanTableDC, NppiDecodeHuffmanSpec *pHuffmanTableAC, NppiSize oSizeROI)
	Huffman Decoding of the JPEG decoding on the host. More...
NppStatus	nppiDecodeHuffmanScanHost_JPEG_8u16s_P3R (const Npp8u *pSrc, Npp32s nLength, Npp32s nRestartInterval, Npp32s nSs, Npp32s nSe, Npp32s nAh, Npp32s nAl, Npp16s *apDst[3], Npp32s aDstStep[3], NppiDecodeHuffmanSpec *apHuffmanDCTable[3], NppiDecodeHuffmanSpec *apHuffmanACTable[3], NppiSize aSizeROI[3])
	Huffman Decoding of the JPEG decoding on the host. More...
NppStatus	nppiEncodeHuffmanSpecGetBufSize_JPEG (int *pSize)
	Returns the length of the NppiEncodeHuffmanSpec structure. More...
NppStatus	nppiEncodeHuffmanSpecInit_JPEG (const Npp8u *pRawHuffmanTable, NppiHuffmanTableType eTableType, NppiEncodeHuffmanSpec *pHuffmanSpec)
	Creates a Huffman table in a format that is suitable for the encoder. More...
NppStatus	nppiEncodeHuffmanSpecInitAlloc_JPEG (const Npp8u *pRawHuffmanTable, NppiHuffmanTableType eTableType, NppiEncodeHuffmanSpec **ppHuffmanSpec)
	Allocates memory and creates a Huffman table in a format that is suitable for the encoder. More...
NppStatus	nppiEncodeHuffmanSpecFree_JPEG (NppiEncodeHuffmanSpec *pHuffmanSpec)
	Frees the memory allocated by nppiEncodeHuffmanSpecInitAlloc_JPEG. More...
NppStatus	nppiEncodeHuffmanScan_JPEG_8u16s_P1R (const Npp16s *pSrc, Npp32s nSrcStep, Npp32s nRestartInterval, Npp32s nSs, Npp32s nSe, Npp32s nAh, Npp32s nAl, Npp8u *pDst, Npp32s *nLength, NppiEncodeHuffmanSpec *pHuffmanTableDC, NppiEncodeHuffmanSpec *pHuffmanTableAC, NppiSize oSizeROI, Npp8u *pTempStorage)
	Huffman Encoding of the JPEG Encoding. More...
NppStatus	nppiEncodeHuffmanScan_JPEG_8u16s_P3R (Npp16s *apSrc[3], Npp32s aSrcStep[3], Npp32s nRestartInterval, Npp32s nSs, Npp32s nSe, Npp32s nAh, Npp32s nAl, Npp8u *pDst, Npp32s *nLength, NppiEncodeHuffmanSpec *apHuffmanDCTable[3], NppiEncodeHuffmanSpec *apHuffmanACTable[3], NppiSize aSizeROI[3], Npp8u *pTempStorage)
	Huffman Encoding of the JPEG Encoding. More...
NppStatus	nppiEncodeOptimizeHuffmanScan_JPEG_8u16s_P1R (const Npp16s *pSrc, Npp32s nSrcStep, Npp32s nRestartInterval, Npp32s nSs, Npp32s nSe, Npp32s nAh, Npp32s nAl, Npp8u *pDst, Npp32s *pLength, Npp8u *hpCodesDC, Npp8u *hpTableDC, Npp8u *hpCodesAC, Npp8u *hpTableAC, NppiEncodeHuffmanSpec *pHuffmanDCTable, NppiEncodeHuffmanSpec *pHuffmanACTable, NppiSize oSizeROI, Npp8u *pTempStorage)
	Optimize Huffman Encoding of the JPEG Encoding. More...
NppStatus	nppiEncodeOptimizeHuffmanScan_JPEG_8u16s_P3R (Npp16s *apSrc[3], Npp32s aSrcStep[3], Npp32s nRestartInterval, Npp32s nSs, Npp32s nSe, Npp32s nAh, Npp32s nAl, Npp8u *pDst, Npp32s *pLength, Npp8u *hpCodesDC[3], Npp8u *hpTableDC[3], Npp8u *hpCodesAC[3], Npp8u *hpTableAC[3], NppiEncodeHuffmanSpec *apHuffmanDCTable[3], NppiEncodeHuffmanSpec *apHuffmanACTable[3], NppiSize oSizeROI[3], Npp8u *pTempStorage)
	Optimize Huffman Encoding of the JPEG Encoding. More...
NppStatus	nppiEncodeHuffmanGetSize (NppiSize oSize, int nChannels, size_t *pBufSize)
	Calculates the size of the temporary buffer for baseline Huffman encoding. More...
NppStatus	nppiEncodeOptimizeHuffmanGetSize (NppiSize oSize, int nChannels, int *pBufSize)
	Calculates the size of the temporary buffer for optimize Huffman coding. More...
NppStatus	nppiDCTInv4x4_WebP_16s_C1R (const Npp16s *pSrc, int nSrcStep, Npp16s *pDst, int nDstStep, NppiSize oSizeROI)
	Inverse DCT in WebP decoding. More...

Hybrid CPU+GPU JPEG Huffman decoding
These functions and structs are used for Huffman decoding part of JPEG decode pipeline. It uses hybrid CPU + GPU approach. See nppiJpegDecodeJob for more documentation and example
enum	NppiJpegDecodeJobKind {   NPPI_JPEG_DECODE_SIMPLE,   NPPI_JPEG_DECODE_PRE,   NPPI_JPEG_DECODE_CPU,   NPPI_JPEG_DECODE_GPU,   NPPI_JPEG_DECODE_MEMZERO,   NPPI_JPEG_DECODE_FINALIZE }
	Type of job to execute. More...
NppStatus	nppiJpegDecodeJobMemorySize (const NppiJpegDecodeJob *pJob, size_t *aSize)
	Calculates sizes of additional buffers used by the job. More...
NppStatus	nppiJpegDecodeJob (const NppiJpegDecodeJob *pJob, const NppiJpegDecodeJobMemory *pMemory)
	Executes a job – part of decoding. More...
NppStatus	nppiJpegDecodeJobCreateMemzero (NppiJpegDecodeJob *pJob)
	Initializes a job that has to be called at the beginning of decoding. More...
NppStatus	nppiJpegDecodeJobCreateFinalize (NppiJpegDecodeJob *pJob)
	Initializes a job that has to be called at the end of decoding, in order to convert temporary representation of DCT coefficients to the final one. More...
size_t	nppiJpegDecodeGetScanDeadzoneSize (void)
	This function returns how much additional memory has to be available after the end of compressed scan data. More...
size_t	nppiJpegDecodeGetDCTBufferSize (NppiSize oBlocks)
	Returns how much memory has to be allocated for DCT coefficient buffers declared in NppiJpegDecodeJobMemory. More...
#define	NPPI_JPEG_DECODE_N_BUFFERS   3
	Number of additional buffers that may be used by JPEG decode jobs. More...

Detailed Description

Image compression primitives.

The JPEG standard defines a flow of level shift, DCT and quantization for forward JPEG transform and inverse level shift, IDCT and de-quantization for inverse JPEG transform. This group has the functions for both forward and inverse functions.

These functions can be found in the nppicom library. Linking to only the sub-libraries that you use can significantly save link time, application load time, and CUDA runtime startup time when using dynamic libraries.

Macro Definition Documentation

#define NPPI_JPEG_DECODE_N_BUFFERS   3

Number of additional buffers that may be used by JPEG decode jobs.

This number may change in the future, but it remain small.

See Also

NppiJpegDecodeJobMemory

Typedef Documentation

typedef struct NppiDecodeHuffmanSpec NppiDecodeHuffmanSpec

typedef struct NppiEncodeHuffmanSpec NppiEncodeHuffmanSpec

Enumeration Type Documentation

enum NppiJpegDecodeJobKind

Type of job to execute.

Usually you will need just SIMPLE for each scan, one MEMZERO at the beginning and FINALIZE at the end. See the example in nppiJpegDecodeJob

SIMPLE can be split into multiple jobs: PRE, CPU & GPU. Please note that if you don't use SIMPLE, you man need to add some memcopies and synchronizes as described in nppiJpegDecodeJob.

See Also

nppiJpegDecodeJob

Enumerator
NPPI_JPEG_DECODE_SIMPLE	Decode whole scan using a single job.
NPPI_JPEG_DECODE_PRE	Preprocessing scan on GPU.
NPPI_JPEG_DECODE_CPU	Part of decoding run on CPU.
NPPI_JPEG_DECODE_GPU	Part of decoding run on GPU.
NPPI_JPEG_DECODE_MEMZERO	Zeroing memory before decoding.
NPPI_JPEG_DECODE_FINALIZE	Change memory representation of DCT coefficients to final.

Function Documentation

NppStatus nppiDCTInv4x4_WebP_16s_C1R	(	const Npp16s *	pSrc,
		int	nSrcStep,
		Npp16s *	pDst,
		int	nDstStep,
		NppiSize	oSizeROI
	)

Inverse DCT in WebP decoding.

Input is the bitstream that contains the coefficients of 16x16 blocks. These coefficients are based on a 4x4 sub-block unit, e.g., Coeffs in 0th 4x4 block, 1st 4x4 block 2nd 4x4 block, etc. Output is the coefficients after inverse DCT transform. The output is put in an image format (i.e. raster scan order), different from the input order.

Parameters

pSrc	Source-Image Pointer.
nSrcStep	Source-Image Line Step.
pDst	Destination-Image Pointer.
nDstStep	Destination-Image Line Step.
oSizeROI	Region-of-Interest (ROI).

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.

NppStatus nppiDecodeHuffmanScanHost_JPEG_8u16s_P1R	(	const Npp8u *	pSrc,
		Npp32s	nLength,
		Npp32s	restartInterval,
		Npp32s	Ss,
		Npp32s	Se,
		Npp32s	Ah,
		Npp32s	Al,
		Npp16s *	pDst,
		Npp32s	nDstStep,
		NppiDecodeHuffmanSpec *	pHuffmanTableDC,
		NppiDecodeHuffmanSpec *	pHuffmanTableAC,
		NppiSize	oSizeROI
	)

Huffman Decoding of the JPEG decoding on the host.

Input is expected in byte stuffed huffman encoded JPEG scan and output is expected to be 64x1 macro blocks.

Parameters

pSrc	Byte-stuffed huffman encoded JPEG scan.
nLength	Byte length of the input.
restartInterval	Restart Interval, see JPEG standard.
Ss	Start Coefficient, see JPEG standard.
Se	End Coefficient, see JPEG standard.
Ah	Bit Approximation High, see JPEG standard.
Al	Bit Approximation Low, see JPEG standard.
pDst	Destination-Image Pointer.
nDstStep	Destination-Image Line Step.
pHuffmanTableDC	DC Huffman table.
pHuffmanTableAC	AC Huffman table.
oSizeROI	Region-of-Interest (ROI).

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.

NppStatus nppiDecodeHuffmanScanHost_JPEG_8u16s_P3R	(	const Npp8u *	pSrc,
		Npp32s	nLength,
		Npp32s	nRestartInterval,
		Npp32s	nSs,
		Npp32s	nSe,
		Npp32s	nAh,
		Npp32s	nAl,
		Npp16s *	apDst[3],
		Npp32s	aDstStep[3],
		NppiDecodeHuffmanSpec *	apHuffmanDCTable[3],
		NppiDecodeHuffmanSpec *	apHuffmanACTable[3],
		NppiSize	aSizeROI[3]
	)

Huffman Decoding of the JPEG decoding on the host.

Input is expected in byte stuffed huffman encoded JPEG scan and output is expected to be 64x1 macro blocks.

Parameters

pSrc	Byte-stuffed huffman encoded JPEG scan.
nLength	Byte length of the input.
nRestartInterval	Restart Interval, see JPEG standard.
nSs	Start Coefficient, see JPEG standard.
nSe	End Coefficient, see JPEG standard.
nAh	Bit Approximation High, see JPEG standard.
nAl	Bit Approximation Low, see JPEG standard.
apDst	Destination-Image Pointer.
aDstStep	Destination-Image Line Step.
apHuffmanDCTable	DC Huffman tables.
apHuffmanACTable	AC Huffman tables.
aSizeROI	Region-of-Interest (ROI).

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.

NppStatus nppiDecodeHuffmanSpecFreeHost_JPEG

(

NppiDecodeHuffmanSpec *

pHuffmanSpec

)

Frees the host memory allocated by nppiDecodeHuffmanSpecInitAllocHost_JPEG.

Parameters

pHuffmanSpec

Pointer to the Huffman table for the decoder

NppStatus nppiDecodeHuffmanSpecGetBufSize_JPEG

(

int *

pSize

)

Returns the length of the NppiDecodeHuffmanSpec structure.

Parameters

pSize

Pointer to a variable that will receive the length of the NppiDecodeHuffmanSpec structure.

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiDecodeHuffmanSpecInitAllocHost_JPEG	(	const Npp8u *	pRawHuffmanTable,
		NppiHuffmanTableType	eTableType,
		NppiDecodeHuffmanSpec **	ppHuffmanSpec
	)

Allocates memory and creates a Huffman table in a format that is suitable for the decoder on the host.

Parameters

pRawHuffmanTable	Huffman table formated as specified in the JPEG standard.
eTableType	Enum specifying type of table (nppiDCTable or nppiACTable).
ppHuffmanSpec	Pointer to returned pointer to the Huffman table for the decoder

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiDecodeHuffmanSpecInitHost_JPEG	(	const Npp8u *	pRawHuffmanTable,
		NppiHuffmanTableType	eTableType,
		NppiDecodeHuffmanSpec *	pHuffmanSpec
	)

Creates a Huffman table in a format that is suitable for the decoder on the host.

Parameters

pRawHuffmanTable	Huffman table formated as specified in the JPEG standard.
eTableType	Enum specifying type of table (nppiDCTable or nppiACTable).
pHuffmanSpec	Pointer to the Huffman table for the decoder

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiEncodeHuffmanGetSize	(	NppiSize	oSize,
		int	nChannels,
		size_t *	pBufSize
	)

Calculates the size of the temporary buffer for baseline Huffman encoding.

See Also

nppiEncodeHuffmanScan_JPEG_8u16s_P1R(), nppiEncodeHuffmanScan_JPEG_8u16s_P3R().

Parameters

oSize	Image Dimension.
nChannels	Number of channels in the image.
pBufSize	Pointer to variable that returns the size of the temporary buffer.

Returns

NPP_SUCCESS Indicates no error. Any other value indicates an error or a warning

NPP_SIZE_ERROR Indicates an error condition if any image dimension has zero or negative value

NPP_NULL_POINTER_ERROR Indicates an error condition if pBufSize pointer is NULL

NppStatus nppiEncodeHuffmanScan_JPEG_8u16s_P1R	(	const Npp16s *	pSrc,
		Npp32s	nSrcStep,
		Npp32s	nRestartInterval,
		Npp32s	nSs,
		Npp32s	nSe,
		Npp32s	nAh,
		Npp32s	nAl,
		Npp8u *	pDst,
		Npp32s *	nLength,
		NppiEncodeHuffmanSpec *	pHuffmanTableDC,
		NppiEncodeHuffmanSpec *	pHuffmanTableAC,
		NppiSize	oSizeROI,
		Npp8u *	pTempStorage
	)

Huffman Encoding of the JPEG Encoding.

Input is expected to be 64x1 macro blocks and output is expected as byte stuffed huffman encoded JPEG scan.

Parameters

pSrc	Destination-Image Pointer.
nSrcStep	Destination-Image Line Step.
nRestartInterval	Restart Interval, see JPEG standard. Currently only values <=0 are supported.
nSs	Start Coefficient, see JPEG standard.
nSe	End Coefficient, see JPEG standard.
nAh	Bit Approximation High, see JPEG standard.
nAl	Bit Approximation Low, see JPEG standard.
pDst	Byte-stuffed huffman encoded JPEG scan.
nLength	Byte length of the huffman encoded JPEG scan.
pHuffmanTableDC	DC Huffman table.
pHuffmanTableAC	AC Huffman table.
oSizeROI	Region-of-Interest (ROI).
pTempStorage	Temporary storage.

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.
• NPP_NOT_SUFFICIENT_COMPUTE_CAPABILITY If the device has compute capability < 2.0.

NppStatus nppiEncodeHuffmanScan_JPEG_8u16s_P3R	(	Npp16s *	apSrc[3],
		Npp32s	aSrcStep[3],
		Npp32s	nRestartInterval,
		Npp32s	nSs,
		Npp32s	nSe,
		Npp32s	nAh,
		Npp32s	nAl,
		Npp8u *	pDst,
		Npp32s *	nLength,
		NppiEncodeHuffmanSpec *	apHuffmanDCTable[3],
		NppiEncodeHuffmanSpec *	apHuffmanACTable[3],
		NppiSize	aSizeROI[3],
		Npp8u *	pTempStorage
	)

Huffman Encoding of the JPEG Encoding.

Input is expected to be 64x1 macro blocks and output is expected as byte stuffed huffman encoded JPEG scan.

Parameters

apSrc	Destination-Image Pointer.
aSrcStep	Destination-Image Line Step.
nRestartInterval	Restart Interval, see JPEG standard. Currently only values <=0 are supported.
nSs	Start Coefficient, see JPEG standard.
nSe	End Coefficient, see JPEG standard.
nAh	Bit Approximation High, see JPEG standard.
nAl	Bit Approximation Low, see JPEG standard.
pDst	Byte-stuffed huffman encoded JPEG scan.
nLength	Byte length of the huffman encoded JPEG scan.
apHuffmanDCTable	DC Huffman tables.
apHuffmanACTable	AC Huffman tables.
aSizeROI	Region-of-Interest (ROI).
pTempStorage	Temporary storage.

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.
• NPP_NOT_SUFFICIENT_COMPUTE_CAPABILITY If the device has compute capability < 2.0.

NppStatus nppiEncodeHuffmanSpecFree_JPEG

(

NppiEncodeHuffmanSpec *

pHuffmanSpec

)

Frees the memory allocated by nppiEncodeHuffmanSpecInitAlloc_JPEG.

Parameters

pHuffmanSpec

Pointer to the Huffman table for the encoder

NppStatus nppiEncodeHuffmanSpecGetBufSize_JPEG

(

int *

pSize

)

Returns the length of the NppiEncodeHuffmanSpec structure.

Parameters

pSize

Pointer to a variable that will receive the length of the NppiEncodeHuffmanSpec structure.

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiEncodeHuffmanSpecInit_JPEG	(	const Npp8u *	pRawHuffmanTable,
		NppiHuffmanTableType	eTableType,
		NppiEncodeHuffmanSpec *	pHuffmanSpec
	)

Creates a Huffman table in a format that is suitable for the encoder.

Parameters

pRawHuffmanTable	Huffman table formated as specified in the JPEG standard.
eTableType	Enum specifying type of table (nppiDCTable or nppiACTable).
pHuffmanSpec	Pointer to the Huffman table for the decoder

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiEncodeHuffmanSpecInitAlloc_JPEG	(	const Npp8u *	pRawHuffmanTable,
		NppiHuffmanTableType	eTableType,
		NppiEncodeHuffmanSpec **	ppHuffmanSpec
	)

Allocates memory and creates a Huffman table in a format that is suitable for the encoder.

Parameters

pRawHuffmanTable	Huffman table formated as specified in the JPEG standard.
eTableType	Enum specifying type of table (nppiDCTable or nppiACTable).
ppHuffmanSpec	Pointer to returned pointer to the Huffman table for the encoder

Returns

Error codes:

• NPP_NULL_POINTER_ERROR If one of the pointers is 0.

NppStatus nppiEncodeOptimizeHuffmanGetSize	(	NppiSize	oSize,
		int	nChannels,
		int *	pBufSize
	)

Calculates the size of the temporary buffer for optimize Huffman coding.

Parameters

oSize	Image Dimension.
nChannels	Number of channels in the image.
pBufSize	Pointer to variable that returns the size of the temporary buffer.

Returns

NPP_SUCCESS Indicates no error. Any other value indicates an error or a warning

NPP_SIZE_ERROR Indicates an error condition if any image dimension has zero or negative value

NPP_NULL_POINTER_ERROR Indicates an error condition if pBufSize pointer is NULL

NppStatus nppiEncodeOptimizeHuffmanScan_JPEG_8u16s_P1R	(	const Npp16s *	pSrc,
		Npp32s	nSrcStep,
		Npp32s	nRestartInterval,
		Npp32s	nSs,
		Npp32s	nSe,
		Npp32s	nAh,
		Npp32s	nAl,
		Npp8u *	pDst,
		Npp32s *	pLength,
		Npp8u *	hpCodesDC,
		Npp8u *	hpTableDC,
		Npp8u *	hpCodesAC,
		Npp8u *	hpTableAC,
		NppiEncodeHuffmanSpec *	pHuffmanDCTable,
		NppiEncodeHuffmanSpec *	pHuffmanACTable,
		NppiSize	oSizeROI,
		Npp8u *	pTempStorage
	)

Optimize Huffman Encoding of the JPEG Encoding.

Input is expected to be 64x1 macro blocks and output is expected as byte stuffed huffman encoded JPEG scan.

Parameters

pSrc	Destination-Image Pointer.
nSrcStep	Destination-Image Line Step.
nRestartInterval	Restart Interval, see JPEG standard. Currently only values <=0 are supported.
nSs	Start Coefficient, see JPEG standard.
nSe	End Coefficient, see JPEG standard.
nAh	Bit Approximation High, see JPEG standard.
nAl	Bit Approximation Low, see JPEG standard.
pDst	Byte-stuffed huffman encoded JPEG scan.
pLength	Pointer to the byte length of the huffman encoded JPEG scan.
hpCodesDC	Host pointer to the code of the huffman tree for DC component.
hpTableDC	Host pointer to the table of the huffman tree for DC component.
hpCodesAC	Host pointer to the code of the huffman tree for AC component.
hpTableAC	Host pointer to the table of the huffman tree for AC component.
pHuffmanDCTable	DC Huffman table.
pHuffmanACTable	AC Huffman table.
oSizeROI	Region-of-Interest (ROI).
pTempStorage	Temporary storage.

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.
• NPP_NOT_SUFFICIENT_COMPUTE_CAPABILITY If the device has compute capability < 2.0.

NppStatus nppiEncodeOptimizeHuffmanScan_JPEG_8u16s_P3R	(	Npp16s *	apSrc[3],
		Npp32s	aSrcStep[3],
		Npp32s	nRestartInterval,
		Npp32s	nSs,
		Npp32s	nSe,
		Npp32s	nAh,
		Npp32s	nAl,
		Npp8u *	pDst,
		Npp32s *	pLength,
		Npp8u *	hpCodesDC[3],
		Npp8u *	hpTableDC[3],
		Npp8u *	hpCodesAC[3],
		Npp8u *	hpTableAC[3],
		NppiEncodeHuffmanSpec *	apHuffmanDCTable[3],
		NppiEncodeHuffmanSpec *	apHuffmanACTable[3],
		NppiSize	oSizeROI[3],
		Npp8u *	pTempStorage
	)

Optimize Huffman Encoding of the JPEG Encoding.

Input is expected to be 64x1 macro blocks and output is expected as byte stuffed huffman encoded JPEG scan.

Parameters

apSrc	Destination-Image Pointer.
aSrcStep	Destination-Image Line Step.
nRestartInterval	Restart Interval, see JPEG standard. Currently only values <=0 are supported.
nSs	Start Coefficient, see JPEG standard.
nSe	End Coefficient, see JPEG standard.
nAh	Bit Approximation High, see JPEG standard.
nAl	Bit Approximation Low, see JPEG standard.
pDst	Byte-stuffed huffman encoded JPEG scan.
pLength	Pointer to the byte length of the huffman encoded JPEG scan.
hpCodesDC	Host pointer to the code of the huffman tree for DC component.
hpTableDC	Host pointer to the table of the huffman tree for DC component.
hpCodesAC	Host pointer to the code of the huffman tree for AC component.
hpTableAC	Host pointer to the table of the huffman tree for AC component.
apHuffmanDCTable	DC Huffman tables.
apHuffmanACTable	AC Huffman tables.
oSizeROI	Region-of-Interest (ROI).
pTempStorage	Temporary storage.

Returns

Error codes:

• NPP_SIZE_ERROR For negative input height/width or not a multiple of 8 width/height.
• NPP_STEP_ERROR If input image width is not multiple of 8 or does not match ROI.
• NPP_NULL_POINTER_ERROR If the destination pointer is 0.
• NPP_NOT_SUFFICIENT_COMPUTE_CAPABILITY If the device has compute capability < 2.0.

size_t nppiJpegDecodeGetDCTBufferSize

(

NppiSize

oBlocks

)

Returns how much memory has to be allocated for DCT coefficient buffers declared in NppiJpegDecodeJobMemory.

The returned value may be bigger than simply number of blocks * 64 * sizeof (short), because decoder may use slightly bigger temporary representation of data.

Parameters

oBlocks

Size of the interleaved component in blocks. (That means that the size of component in blocks has to be aligned according to subsampling of this component and frame).

This function assumes no ununsed space between rows, so at the end stride = oBlocks.width * 64 * sizeof (short).

size_t nppiJpegDecodeGetScanDeadzoneSize

(

void

)

This function returns how much additional memory has to be available after the end of compressed scan data.

The following buffers: pCpuScan and pGpuScan in NppiJpegDecodeJobMemory should have size at least pScan->length + nppiJpegDecodeGetScanDeadzoneSize().

The additional memory is needed because the decoder may perform some speculative reads after the end of compressed scan data.

NppStatus nppiJpegDecodeJob	(	const NppiJpegDecodeJob *	pJob,
		const NppiJpegDecodeJobMemory *	pMemory
	)

Executes a job – part of decoding.

Parameters

pJob	has to be initialized by nppiJpegDecodeJobCreateMemzero or nppiJpegDecodeJobCreateFinalize or manually.
pMemory	has to point to valid structure, except for MEMZERO and FINALIZE scans, for which it can be NULL.

See Also

nppiJpegDecodeJobMemorySize

nppiJpegDecodeJobCreateMemzero

nppiJpegDecodeJobCreateFinalize

This function can be used in two ways, depending on how much control do you need:

1. Decode whole scan in one job. That is accomplished when the job.eKind is set to NPPI_JPEG_DECODE_SIMPLE. Nppi function handless all in-scan synchronization (if needed). This is described in example.
2. Split decoding of scan into multiple jobs. In this case, caller is responsible necessary synchronizations. If multiple jobs from the same scan claim to use the same additional buffer, it means that the jobs are exchaning information throught this buffer and the buffer should not be reused or reallocated meanwhile, additionaly if the buffer is used first by PRE job, and then by CPU job, caller has to call cudaStreamSynchronize before CPU job. NppiJpegDecodeJobKind for more information.

Example (pseudo)code for decoding JPEG: (Error handling code omitted for brevity. Each function which may return an error should be checked)

// Allocate DCT buffers (using nppiJpegDecodeGetDCTBufferSize)

NppiJpegFrameDescr frame;
// Fill frame info...
NppiJpegScanDescr scan;
NppiJpegDecodeJob job;
job.pFrame = frame;
job.pScan = scan;

nppiJpegDecodeJobCreateMemzero(&job);
nppiJpegDecodeJob(&job, NULL);
for (int i = 0; i < nScans; ++i)
{
    // Fill scan info...
    job.eKind = NPPI_JPEG_DECODE_SIMPLE;

    size_t sizes[NPPI_JPEG_DECODE_N_BUFFERS];
    nppiJpegDecodeJobMemorySize(&job, sizes);

    NppiJpegJobMemory memory;
    // Allocate and fill scan buffers (using nppiJpegDecodeGetScanBufferSize)...
    // Fill the memory struct according to sizes...

    nppiJpegDecodeJob(&job, &memory);

    // Synchronization is needed only if you reuse buffers between scans. 
    cudaStreamSynchronize(nppGetStream());
}

nppiJpegDecodeJobCreateFinalize(&job);
nppiJpegDecodeJob(&job, NULL);

// Perform further steps of decoding (iDCT etc.)
* 

Returns

• NPP_SUCCESS
• NPP_BAD_ARGUMENT_ERROR when the scan doesn't represent valid JPEG scan
• NPP_NULL_POINTER_ERROR when one of necessary arguments of buffers is NULL
• NPP_ERROR when encountered CUDA error

NppStatus nppiJpegDecodeJobCreateFinalize

(

NppiJpegDecodeJob *

pJob

)

Initializes a job that has to be called at the end of decoding, in order to convert temporary representation of DCT coefficients to the final one.

Parameters

pJob,:

pJob.pFrame should point to valid frame description *pJob.pScan will be overwritten.

NppStatus nppiJpegDecodeJobCreateMemzero

(

NppiJpegDecodeJob *

pJob

)

Initializes a job that has to be called at the beginning of decoding.

Parameters

pJob,:

pJob.pFrame should point to valid frame description. *pJob.pScan will be overwritten.

If the caller had manually zeroed the memory for DCT buffers, (note: whole nppiJpegDecodeGetDCTBufferSize has to be zeroed). this job doesn't have to be executed.

NppStatus nppiJpegDecodeJobMemorySize	(	const NppiJpegDecodeJob *	pJob,
		size_t *	aSize
	)

Calculates sizes of additional buffers used by the job.

Parameters

	pJob	has to point to properly initialized job
[out]	aSize	will be filled with NPPI_JPEG_DECODE_N_BUFFERS sizes, aSize[i] telling how much memory has to be allocated for apCpuBuffer[i] and apGpuBuffer[i].

See Also

NppiJpegDecodeJobMemory

Returns

• NPP_SUCCESS
• NPP_BAD_ARGUMENT_ERROR when the scan doesn't represent valid JPEG scan
• NPP_NULL_POINTER_ERROR when one of necessary arguments is NULL