Abstract: A method and an apparatus to encode a series of quantized coefficients of a transform of a block of image data. The transform is such that 0 is the most likely coefficient amplitude and 1 is the next most likely coefficient amplitude. The method includes forming modes for each encountered non-zero amplitude and forming events for the modes in the mode-modified series formed by setting to zero all non-zero amplitudes other than the amplitude defining the mode. An event for modes for amplitudes greater than 1 is a run of none or more zero-valued coefficients followed a non-zero amplitude in the mode-modified series. In one embodiment, a first mode is defined for amplitude 1 wherein an event is a run of none or more zero-valued coefficients followed the amplitude 1 coefficient in the mode-modified series.

Abstract: A set of processes are disclosed for compressing and decompressing bitmapped picture files that are to be stored for later display within a control for an HVAC system. The compression process includes an examination of the first bitmapped pixel in a given bitmapped file followed by a counting of the number of consecutive pixels having the same state as the first pixel. The process continues with analyses of successive numbers of pixels of first one state and then another state and generating a numerical representations as to each number of so counted pixels until the last pixel of the bitmapped picture file data is analyzed. The resulting compressed file is stored in a memory within a control for an HVAC system so that the file can thereafter be read when the file is to be displayed.

Abstract: In a system for variable-length coding, when image data of a plurality of documents are compressed and stored in a compression memory, the image data is divided into a plurality of areas. Then, attributes are discriminated for each area, and the result of the attribute discrimination is written to an attribute memory. Attribute counters count the numbers of the discriminated attributes. A variable-length compression section compresses the code data with a compression method in response to the attribute data written to the attribute memory, and the compressed is written to a compression memory.

Abstract: Methods, apparatus, and computer readable medium for compressing connected component objects (300) of bi-level images. The compression apparatus (204) can take various forms including apparatus for coding a stroke of an object (300) or for coding the entirety of the object (300), including plural strokes. The compression apparatus (204) typically includes a referencing module (205) for identifying at least one reference node (310), a coding module (206) for successively coding pixel runs (311-314) such that at least one run (311) is coded relative to the reference node (310) and other runs (312-314) are coded relative to previously coded runs, and a closing module (207) for terminating the process. Certain forms of the apparatus operate in a horizontal or a vertical mode only, never operate in horizontal mode during two consecutive coding operations, code each run using two code-words, and/or utilize modified Huffman coding techniques.

Abstract: Disclosed is a method of compressing data contained in variable length or universal variable length code words to be carried in a digital bitstream. The method includes formatting a first set of code words for data and then constructing a second set of code words containing code words from the first set as well as concatenations of code words from the first set. Code words from the second set are to carry data in compressed form in the digital bitstream. One way in which the concatenation is accomplished includes selecting a code word from said first set of code words and applying it as a prefix to itself and to all of the other words in the first set, thereby constructing the second set. The code word selected from the first set for application as a prefix may be the shortest code word of the first set.

Abstract: Images are to be efficiently and easily encoded while suppressing block distortion and pseudo-contour generation. A quantization characteristics determining unit receives pixel values from a pixel value input unit, measures the length S of the consecutive occurrence of the same pixel values in connection with a pixel to be encoded and the pixel value differences D, and determines quantization characteristics n with reference to the result of sensory evaluation. A quantization/inverse quantization unit quantizes pixel values to be inputted with the quantization characteristics n, and further inverse quantizes them to reduce the number of gray-scale levels. The output pixel values of the quantization/inverse quantization unit are encoded and outputted by an entropy encoding unit.

Abstract: JPEG data is efficiently recompressed and transmitted to a remote color facsimile device. Before transmission of recompressed JPEG data, an anticipated transmission time is displayed for enabling the user to easily select the desired compression ratio. To generate recompressed JPEG, a Huffman decoder is provided for decoding encoded data and temporarily generates decoded data. Table generator multiplies the predefined quantization table values by the prescribed value to generate the modified quantization table. Intermediate data generator generates the intermediate data by dividing the encoded data by ratio n, which is derived by dividing predefined quantization table by the modified quantization table. Huffman encoder encodes the intermediate data to create new encoded data. Recompressed JPEG data includes the newly coded data and the modified quantization table.

Abstract: A method that decodes serially received MPEG variable length codes by executing instructions in parallel. The method includes an execution unit which includes multiple pipelined functional units. The functional units execute at least two of the instructions in parallel. The instructions utilize and share general purpose registers. The general purpose registers store information used by at least two of the instructions.

Abstract: A system for inserting an increased amount of information into DCT coefficients generated in blocks from image data is disclosed. Additional information is first inserted into input DCT coefficients in a block by changing at least one DCT coefficient of the input DCT coefficients to produce changed DCT coefficients. A level of one DCT coefficient selected from the changed DCT coefficients in the block is corrected to produce corrected DCT coefficients. The one DCT coefficient is selected so that a total code length of codes generated from the corrected DCT coefficients is equal to an original total code length of codes generated from the input DCT coefficients in the block.

Abstract: A method is disclosed for decoding multiple-coded symbols from a coded input symbol stream in a single clock cycle. The method constructs an original Huffman look-up table by extending the associated Huffman tree to decode multiple symbols in one clock cycle in a first embodiment and decodes multiple DCT coefficient symbols in an alternate embodiment. An advantage of the method is that the depth of the new Huffman tree is adjustable thereby making the method easily adaptable to various hardware architectures. A further advantage of the present invention is that the decoding process speed is significantly increased while the size of the look-up table is nominally increased.

Abstract: The coded block parameters used to code blocks of image samples into structures called macroblocks are compressed more efficiently by exploiting the correlation between chrominance and luminance blocks in each macroblock. In particular, the coded block pattern for chrominance and luminance are combined into a single parameter for the macroblock and jointly coded with a single variable length code. To further enhance coding efficiency, the spatial coherence of coded block patterns can be exploited by using spatial prediction to compute predicted values for coded block pattern parameters.

Abstract: Image encoding apparatus 10 according to the present invention is an image encoding apparatus 10 for dividing image signals into blocks, performing an orthogonal transform of each block, reading resultant orthogonal transform coefficients to obtain a coefficient string, and performing entropy coding, which has block selector 14 for selecting a size of a block for the orthogonal transform, out of a plurality of blocks of different sizes; coefficient string divider 12 for, when a block of a size larger than a minimum size is selected by block selector 14, dividing a coefficient string in the block into a plurality of coefficient strings of a length equal to that of a coefficient string in a block of the minimum size; and encoder 13 for performing entropy coding adapted to the coefficient string in the block of the minimum size. This substantializes the image encoding apparatus capable of achieving efficient entropy coding in the orthogonal transform of variable sizes.

Abstract: A method and apparatus are disclosed for symmetrically compressing and decompressing video information in real time by coupling block and wavelet techniques. In the compression pipeline, the image is divided into blocks comprising 2k×2k pixels (in the preferred embodiment, k=1). The average color of each block is computed. The system computes an average luminance for each block and differential luminances of each pixel of the plurality of pixels of each block. A first plurality of frequency details of each block are determined by Haar transforming the differential luminances. The system computes an average color difference between each block and the preceding block, and quantizes the average color difference and the first plurality of frequency details using Lloyd-Max quantization. In an alternate embodiment, skip codes are generated for blocks having the same quantized average color difference and second plurality of frequency details.

Abstract: JPEG (Joint Photographic Experts Group) images are encoded and decoded as fast as possible for a variety of disparate applications. A novel structure stores the 8×8 Discrete Cosine Transform (DCT) blocks after entropy decoding in a JPEG decoder or after the Forward Discrete Cosine Transform (FDCT) in the JPEG encoder to use as an intermediate format between transform processes. The format was chosen to speed up the entropy decode and encode processes and is based on the information needed for the JPEG Huffman entropy coding, but lends itself to fast execution of other DCT based transforms, including arithmetic entropy coding.

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: In the present invention, the appearance frequency of all image information items to be encoded is determined, short code words are allocated from predetermined code words in accordance with leaves of a bifurcating scheme to image information items having an appearance frequency up to a predetermined ranking, in sequential fashion starting from the image information item having the highest appearance frequency, and a predetermined identifier is appended to the beginning of each of the remaining image information items, the resulting codes being taken as the respective code words allocated to said remaining image information items. Thereby, it is possible to provide an image information encoding method whereby decoding by hardware can be performed readily.

Abstract: The present invention includes methods and apparatus for attaining high speed coding and decoding. A first method decreases the number of memory access times by performing signal format conversion, orthogonal transform and continuous variable-length coding with predetermined small areas in a frame used as units. A second method omits orthogonal transform computation by using orthogonal transform coefficients to shorten the processing time. A third method uses additions and subtractions for orthogonal transform thereby decreasing the number of registers used and reducing the number of memory access times. The present invention further includes a decoding method for variable-length decoding wherein table size is not made larger because the number of table access times per code word is set to a maximum of 2, and plural code words are decoded by one tale access operation to attain high-speed decoding.

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: A variable length encoding apparatus such as an encoding apparatus using the MPEG standard, wherein without degrading the precision of quantization step, the generated code bit amount is limited. Encoding is performed at the quantization step of required picture quality by an encoding part 106, and a bit stream 141 is written in an external memory 101. The generated encoded bit amount is measured from the increment of a write pointer 121 increased because of the writing in the external memory 101 by a control unit 107. If the amount is larger than a preset value, the data is replaced with data leading to the same decoding result as those of the preceding or following reference picture by using a replacement pattern in accordance with the picture type and the position on a times series, and the data is written in the external memory 101, thus outputting the data as an output bit stream 111 controlled to the generated code amount within an upper limit value.

Abstract: The present invention provides a system, device, computer program product, and method for representing a plurality of electronic ink data points. According to one embodiment, the system includes a first computing device having a writing stylus, a handwriting capture interface, a processing element and a transmitter. The handwriting capture interface captures a plurality of electronic ink data points based upon a position of the writing stylus, while the processing element is capable of determining a derivative of at least the second order of the electronic ink data points. The transmitter transmits data representative of the high-order derivative of the electronic ink data points. The system also includes a second computing device capable of receiving the data. The second computing device includes a processing element for reconstructing the electronic ink data points based upon the high-order derivative and independent of all but one of the electronic ink data points originally captured.

Abstract: The variable length code tables 10 are categorized into the first and second table groups, and a set of the entire bits of reference data consisting of variable length codes and part of bits of the table designation data for designating a table to which the reference data is referred, are inputted to the first table group, whereas a set of part of the bits of the reference data and the entire bits of the table designation data are inputted to the second table groups. Then, an output of either one of the first and second tables is selected by a selector of 2:1, and thus variable length decode data is obtained.

Abstract: Methods, devices and systems for compressing images are provided. One method includes creating halftone mask structures and applying compression coding techniques to arrayed pixels sorted using the halftone mask structures in order to convert an image to a compressed bi-level, halftoned image.

Abstract: The coded block parameters used to code blocks of image samples into structures called macroblocks are compressed more efficiently by exploiting the correlation between chrominance and luminance blocks in each macroblock. In particular, the coded block pattern for chrominance and luminance are combined into a single parameter for the macroblock and jointly coded with a single variable length code. To further enhance coding efficiency, the spatial coherence of coded block patterns can be exploited by using spatial prediction to compute predicted values for coded block pattern parameters.

Abstract: Apparatus and methods are provided for encoding video data in a manner which significantly reduces the computation performed by the video encoder and the video decoder without suffering any degradation in the perceived quality of the compressed video data. In particular, apparatus and methods are provided for determining which blocks might be zeroed out after quantization. This determination is performed after motion estimation, the classification of the frame as either an I frame, P frame, or a B frame, and the determination of a quantization step size (QP) for the block, but before DCT. If a given block is determined to be a “zero” quantized block, then the DCT, quantization, zig-zag scan and variable length coding steps are omitted, and a variable length code output is provided indicating that the block B is a “zero” quantized block.

Abstract: Further compression of data allowing economical storage of data for extended periods of time in high-speed access memory is performed in reduced time by performing further compression during transcoding in the transform domain and without restoring image data to its original image data form. The reduction in processing time is achieved by exploiting the large number of zero-valued quantization transform coefficients and not changing quantized transform coefficients at zig-zag scan positions where non-zero coefficients are rare during range reduction of the entropy decoded quantized transformed data. The range can be restored by computation or estimation of an altered quantization table which is stored with the further compressed a quantization values. Further advantages accrue from use of JPEG packed format for the data during transcoding.

Abstract: A system and method that prevent an input of variable length codes in which short length codes continue from being interrupted without an increase of a circuit scale are provided. The system comprises a variable length decoding device for decoding variable length codes, a buffer for buffering the variable length codes to be supplied to the variable length decoding device, a detector for detecting whether or not a occupation rate of the variable length codes in the buffer has increased, and a discarder for discarding the variable length codes to be supplied to the buffer when the detected result by the detector represents that the occupation rate of the variable length codes in the buffer has increased. The system further comprises an elementary stream extractor, disposed between the discarding device and the buffer, for extracting an elementary stream defined in MPEG standard.

Abstract: A data reading apparatus reads variable length-coded data. A digital signal processor of this data reading apparatus executes a code word reading step of sequentially reading a series of code words partitioned by a plurality of resynchronization markers, and a resynchronization marker detecting step of detecting a next resynchronization marker before a reading position in the code word reading step reaches the next resynchronization marker.

Abstract: A pattern matching coding device for conducting coding of a unit pattern based on pattern matching with a library pattern, which device, as to a mark pattern determined to be matching, when the number of match error pixels of the pattern is not more than a prescribed value, codes, without coding the bit map, an identification ID of a matching bit map in a library and an identification flag indicating that the number of match error pixels is not more than the prescribed value.

Abstract: The present invention is embodied in a data compression encoder for use with the discrete cosine transform compression process. The invention enhances compression using the discrete cosine transform by utilizing a prediction engine that breaks the data received into predicted and unpredicted portions. The predicted portions are excluded from the discrete cosine transform reducing the time-required to compress a file. The prediction engine relies, in part, upon look-up tables that are used to determine the predicted blocks. A table build engine and database compiler are used to create the look-up tables.

Abstract: The invention relates to a method of variable length coding in which data symbols are arranged into a number of sets, each of which comprises at least a first data symbol. At least two sets of variable length codewords are provided for variable length coding the data symbols and the sets of data symbols are variable length coded in a coding sequence, starting from a first set and progressing to a last set of data symbols. For a given set of data symbols, other than the first set of data symbols in the coding sequence, a set of cumulative information measures is determined, each of which is representative of a total amount of information required to variable length code the first data symbols of all the sets of data symbols preceding the given set of data symbols in the coding sequence using a predetermined one of the at least two sets of variable length codewords.

Abstract: The present invention discloses a dynamic image encoding apparatus and a method for encoding a dynamic image in which the dynamic image is divided into data blocks, the data blocks are encoded, and then block division information including a size of a picture or a size of the encoded data blocks is inserted at a position after a synchronous code in a header of each group including a plurality of the encoded data blocks when the groups are transmitted.

Abstract: A decoding LSI adaptable to MPEG4 is provided with a padding means for performing padding on decoded texture data, an arithmetic decoding means for performing arithmetic decoding on coded shape data, and a composition means for compositing a plurality of texture data to generate composite image data. The padding means, the arithmetic decoding means, and the composition means are implemented by hardware circuits, i.e., a padding engine, an arithmetic decoding engine, and a composition engine, respectively. Therefore, the decoding LSI can perform high-speed decoding on a bitstream corresponding to plural objects, such as images, which are compressively coded by the MPEG4 coding method, with reduced cost of the hardware circuits performing the decoding process.

Abstract: A system and method for compressing an image into bit streams allows data to be presented in either lossy or lossless quality. A lossy quality presentation results in some measurable degradation of an image's visual quality upon expansion. A lossless quality presentation displays the image in its original form. The method divides the image to be compressed into a plurality of regions. For each region, a plurality of adjacent pixels are selected and organized into a set. The corresponding sets for each respective region are identified as a group. The pixel sets within each group are encoded and arranged into two bit streams associated with each respective group. Next, each group's respective bit streams are written into a primary bit stream of constant size and possibly a supplemental bit stream of variable length for presenting the image in either lossy or lossless quality.

Abstract: The present invention selectively applies one of VLC tables stored in a memory for encoding a coded block pattern of a macroblock according to the number of blocks having an object within the macroblock, the number of blocks obtained using shape information, thereby reducing the amount of data transmitted and increasing coding efficiency.

Abstract: The present invention provides a high speed MMR compression processing method by reducing the number of times of repeating a process of finding the positions of changing pixels a1, a2, b1, and b2. According to this method, first, a bit string corresponding to pixel data is obtained from an image. Then, data are sequentially fetched from the bit string byte by byte. Subsequently, a search is made of a table that describes the number of consecutive bits that are arranged to the right of and have the same color as each of bits of each byte of all bit patterns represented by bits included in the fetched 1 byte. Then, the number of consecutive bits, which are arranged to the right of and have the same color as each of bits of each of the fetched bytes, is detected according to the bit patterns represented by bits of the fetched byte. Subsequently, a pixel placed at the position corresponding to the number obtained by adding 1 to the detected number of consecutive bits is determined as a color changing pixel.

Abstract: The invention provides an image encoding apparatus/method capable of inputting image data, quantizing the image data, variable length encoding the quantized image data, detecting the code length of the encoded image data, storing the encoded image data in a predetermined memory area of memory means, discriminating whether the detected code length exceeds the permissible memory range of the predetermined memory area, and, in case the permissible memory range is exceeded, terminating the storage operation in the memory area and continuing the encoding process and the detection process and setting the quantization parameter of the quantization process according to the result of detection of the detection process.

Abstract: A lossless compression mechanism for compressing and restoring data elements such as text, text formatting, video, audio, speech, and 2D and 3D graphical information. Each data element is compressed using a data structure having a bin number field and an offset field. The bin number field is associated to a bin having a range of values which includes the data element value. The offset field is computed from a minimum bin value, wherein the minimum bin value is associated to the bin and is stored in a bin lookup table. The bin number field is encoded using a unary code, and the offset is encoded using a binary code.

Abstract: A variable length coding method and apparatus is provided. The variable length coding method includes the steps of analyzing the occurrence statistics of symbols with respect to previous frames, generating a mapping table for variably mapping input symbols to bit patterns based on the analyzed occurrence statistics of the input symbols, resetting the mapping relationship between symbols and bit patterns based on the generated mapping table, and variable length coding a current frame based on the reset mapping relationship. The variable length coding method efficiently reduces the number of bits generated by dynamically varying the mapping between input symbols and bit patterns depending on the occurrence statistics of the input symbols.

Abstract: An image compression apparatus transforms original image data partitioned into first blocks, each of which is composed of a plurality of pixels, to reduced-image data composed of a smaller number of pixels than that of the original image data. Further, the apparatus generates expanded-image data from the reduced-image data by fluency transform. Based on the expanded-image data and the original image data, differential value data is obtained, and the differential value is transformed to differential DCT coefficient data by DCT processing. Based on the differential DCT coefficient data, a code-length corresponding to a bit-length necessary for a Huffman coding is calculated. The fluency transform has a plurality of modes, each mode being selected in order, the code-length being calculated for all of the modes. Then, a mode which makes the code-length minimum is determined as the optimum mode. The differential DCT coefficient data is Huffman encoded, so that Huffman-encoded bit data is generated.

Abstract: The present invention is a method for representation of sign in an encoding scheme. An embodiment of the present invention provides a variable bit length binary representation of the absolute value of integer data and then appends a single bit representing the sign of the original integer data. According to one embodiment, the present invention uses the trailing sign bit to specify the sign of the integer being coded. This scheme is much simpler to encode and decode than other schemes that use sign representations for variable-length bit sequences, especially for data that is roughly symmetric about zero, or can be efficiently mapped to this rough symmetry. In another embodiment, if the present invention is used on data sets where there is a most frequently occurring value, the locations of the most frequently recurring value are exhaustively cataloged through some other means, and the variable-length codes are modified to remove the representation of this value.

Abstract: For the entropy coding of image data after subjected to orthogonal transforation and quantization, a plurality of entropy coding units are provided in parallel. The plurality of entropy coding units can be operated efficiently and the entropy coding can be executed at high speed.

Abstract: An apparatus and method of intraframe encoding of digital frequency-domain data. The data comprises a plurality of slices each having a plurality of blocks. Each block has a DC component and a plurality of AC components. A first DC component value of each slice is encoded. Each subsequent DC component value of each slice is represented as the difference between it and the DC component value preceeding it. For lossless encoding, the initial DC component value of each slice and the differences are encoding using Golomb-Rice.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: A data compression method and system that include the substitution of a substring of data characters located at a first position in a stream of data characters with a substitution code. The substitution code includes a reference to a previous position in the stream of data characters at which is located a substring of data characters that matches the substring of data characters which are being substituted located at the first position. The substitution code also includes an indication of the size of the substituted substring. The reference in the substitution code is a backwards offset to the previous position relative to the first position. According to a further aspect, Huffman encoding can be applied to the backward offsets, the substring lengths, the consecutive literal character lengths, and the literal characters themselves to reduce the data requirement size.

Abstract: A system and method to perform context-adaptive variable length decoding (CAVLC) of transform coefficient levels for block-based motion-compensated decoding of moving pictures, corresponding to transform coefficients. The system and method includes complexity-reduction improvements in the coefficient level decoding process, such as simplified and extended range of Lev-VLC tables. Specifically, the number of Lev-VLC tables is extended from 5 to 7 and only 1 escape code (28-bit escape code) is used for tables Lev-VLC1to Lev-VLC6. The system and method also includes a simplified and improved table selection process. The table selection for the first Coefficient_level after trailing ones depends on total number of non-zero coefficients and number of trailing ones which are local variables within the CAVLC module.

Abstract: In an image decoding apparatus that generates a decoded image from a code sequence. The decoding apparatus has a bus, a computer and a memory, wherein the computer and the memory are connected to each other via the bus. The code sequence is generated by performing orthogonal transform, quantization and entropy coding on image data, which is stored in the memory. The decoding apparatus includes an entropy decoding unit, achieved by the computer, for reading one code out of the code sequence, which is stored in the memory, via the bus and performing entropy decoding on the read code in to generate a decode value. The apparatus also includes a coefficient generating unit, achieved by the computer, for generating at least one orthogonal transform coefficient according to the generated decode value. Also, a writing unit is achieved by the computer, for writing the generated at least one orthogonal transform coefficient into the memory via the bus.

Abstract: The data transfer is repeatedly performed through a path constituted of an image holding RAM→a Huffman decoding circuit→an inverse quantization circuit→a quantization circuit→a Huffman encoding circuit until a code amount of compression image data generated by the Huffman encoding circuit becomes equal to or smaller than a maximum value determined according to an image quality, and thus a quantization threshold value and a Huffman code are determined. Every time the process is repeated, the quantization threshold value stored in a table of a first RAM and a Huffman code stored in a table of a second RAM corresponding to the quantization circuit and the Huffman encoding circuit, respectively, are newly set to a slightly higher value. As a quantization threshold value to be set in a table of a third RAM corresponding to the inverse quantization circuit, a quantization threshold value set in the first RAM at the previous quantization is used.

Abstract: A method of variable length coding classifies each received symbol into one of a plurality of classifications having a corresponding variable length code table selected based upon a probability distribution of received symbols within the classification. The variable length codeword output corresponds to the received symbol according to the variable length code table corresponding to the classification of that received symbol. The plurality of classifications and the corresponding variable length code tables may be predetermined and fixed. Alternatively, the variable length code table may be dynamically determined with data transmitted from encoder to decoder specifying the variable length code tables and their configurations. Universal variable length code (UVLC) is used to code the symbols. Universal variable length code can instantiate to different variable length code tables with different parameters.

Abstract: By combining a plurality of encoding methods actively, an encoding efficiency is enhanced. The first encoder encodes a result of determination whether a prediction error is zero or not. The second encoder encodes the prediction error unless the prediction error is zero. The third encoder encodes the prediction error regardless of whether the prediction error is zero or not. The mode determinator determines the encoding mode, and the encoding controller selectively operates the first encoder, the second encoder, and the third encoder according to the encoding mode determined.

Abstract: A variable length coding (VLC) method and a variable length coding apparatus for producing variable length coding having a reduced number of arithmetic cycles. The method includes carrying out (a) performing a VLC process and assigning a code to a combination of (Last, Run, Level), (b) subtracting LMAX as the maximum Level corresponding to (Last, Run) from Level to calculate amended Level and thereafter assigning a code to a combination of (Last, Run, amended Level), (c) subtracting a value that is obtained by adding 1 and RMAX as the maximum Run corresponding to (Last, Level) from Run to calculate amended Run and thereafter assigning a code to a combination of (Last, amended Run, Level), and (d) of performing faxed length coding (FLC) assignment in parallel with each other, and includes (e) selecting the code according to predetermined priorities.