Abstract: An image coding apparatus includes a variable length coding section, an arithmetic coding section and a common buffer memory. The variable length coding section inputs image data and outputs a binarized code sequence applied with variable length coding. The arithmetic coding section applies arithmetic coding to the binarized code sequence outputted from the variable length coding section. The common buffer memory transmits and receives data between the variable length coding section and the arithmetic coding section.

Abstract: A system, computer program product and method are provided that smooth handwritten information following the transmission of handwritten data to a second computing device, thereby reducing the memory, processing and communications bandwidth requirements of a first computing device that captured the handwritten information. A system, computer program product and method are also provided for creating new points in the vicinity of at least some of the data points of the handwritten data after transmission of the data, thereby effectively improving the resolution of the handwritten information without increasing the memory, processing and communications bandwidth requirements of the first computing device.

Abstract: The invention provides systems and methods for providing compressed video data from multiple bit streams. The systems and methods apply a two-stage strategy. In the first stage, a conditioning step is performed on a bit stream comprising compressed video data which outputs a conditioned bit stream that is able to receive digital insertions without subsequent decompression of the compressed video data or removal from network packets. The conditioning includes recoding an incoming bit stream such that compressed video data in the bit stream immediately before and after a splice point does not have temporal reliance across the splice point. In the second stage, e.g., at a downstream network device, splicing of compressed video data from a second bit stream into the conditioned bit stream is performed. The splicing takes advantage of the changes made to the conditioned bit stream and may occur at the network packet level.

Abstract: A compression system and method for a bit-plane is disclosed. A run-length encoder is used to compress a first block of an image, which includes at least a first line in the image. An offset encoder is used to compress a second block of the image, which includes a number of lines different from the first line.

Abstract: Provided are a method, system, and article of manufacture for converting image data in an input color space to an output color space in a transform domain. An input block of coefficients in an input color space is generated, wherein the input block includes a first type coefficient and a plurality of second type coefficients. The first type coefficient in the input block is converted to an output value in an output color space. The output value is used to determine a scaling factor for the second type coefficients. The scaling factor is applied to the second type coefficients to determine second type coefficients in the output color space. A component output block of coefficients in the output color space is formed from the output value for the first type coefficient and the determined second type coefficients in the output color space.

Abstract: Provided are a method, system, and article of manufacture for determining whether to convert image data in an input color space to an output color space in a transform domain or real domain. An input block of coefficients in an input color space is generated, wherein the input block includes a first type coefficient and a plurality of second type coefficients. The first type coefficient in the input block is converted to an output value in an output color space. A determination is made as to whether real domain processing is required. The input block is converted in a transform domain to an output block of coefficients in the transform domain in an output color space in response to determining that the output value does not require real domain processing.

Abstract: A method and system of lossless adaptive Golomb/Rice (G/R) encoding of integer data using a novel backward-adaptive technique having novel adaptation rules. The adaptive G/R encoder and decoder (codec) and method uses adaptation rules that adjust the G/R parameter after each codeword is generated. These adaptation rules include defining an adaptation value and adjusting the G/R parameter based on the adaptation value. If the adaptation value equals zero, then the G/R parameter is decreased by an integer constant. If the adaptation value equals one, then the G/R parameter is left unchanged. If the adaptation value is greater than one, then the G/R parameter is increased by the adaptation value. In addition, the adaptive G/R encoder and method include fractional adaptation, which defines a scaled G/R parameter in terms of the G/R parameter and updates and adapts the scaled G/R parameter to slow down the rate of adaptation.

Abstract: A method comprises determining a plurality of time intervals Tp and Tn within a variable bit rate (VBR) representation of an image sequence. The time intervals Tp are those in which a number of blocks of information per unit time is greater than a baseline value. The time intervals Tn are those in which a number of blocks of information per unit time is less than the baseline value. A second representation of the image sequence is created in which some blocks of information Bp are removed from the time intervals Tp and interlaced with blocks of information Bn in the time intervals Tn to reduce a variation in a number of blocks of information per unit time between the time intervals Tp and Tn.

Abstract: A plurality of band-limited images is produced from an original image. A transformed image is produced by processing each pixel value in the band-limited images so that the absolute value of an output value does not exceed that of an input value. The processing is non-linear transformation processing. If the absolute value of the input value does not exceed a predetermined threshold value, the absolute value of the output value increases as that of the input value increases, or if it exceeds the predetermined threshold value, the absolute value of the output value does not exceed that of an output value corresponding to the threshold value. Pixel values in the transformed image are multiplied by a predetermined subtraction coefficient, and subtracted from pixel values in the original image to obtain pixel values in a processed image. A compressed image is produced by performing entropy encoding on the processed image.

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: An adaptive entropy coder is coupled with a localized conditioning context to provide efficient compression of images with localized high frequency variations. In one implementation, an arithmetic coder can be used as the adaptive entropy coder. The localized conditioning context includes a basic context region with multiple context pixels that are adjacent the current pixel, each of the context pixels having an image tone. A state is determined for the basic context region based upon a pattern of unique image tones among the context pixels therein. An extended context region that includes the basic context region is used to identify a non-local trend within the context pixels and a corresponding state. A current pixel may be arithmetically encoded according to a previously encoded pixel having the same tone or as a not-in-context element. In one implementation, a not-in-context element may be represented by a tone in a color cache that is arranged as an ordered list of most recent not-in-context values.

Abstract: In the structure for image data having image components of three channels and a transmission ratio component of one channel, the image data structure includes an image area in which the image components of three channels are recorded in a compressed format, and a transmission ratio area which has the same data structure as that of the image area and in which a transmission ratio component and pseudo components of two channels having the same compression format as that of the image components are recorded.

Abstract: A system is described that comprises a method and apparatus for further compressing an already compressed data stream, using a mathematical exclusive-OR computation. The method comprises: receiving a data stream that has been compressed using a first compression protocol; decompressing the data stream using the first compression protocol; reducing temporal redundancy in the data stream using an exclusive-OR comparison protocol; and recompressing the data stream using the first compression protocol. The apparatus comprises: a decompression unit to receive and decompress a compressed data stream to produce decompressed data; an exclusive-OR comparison unit, coupled to the decompression unit, to perform a mathematical exclusive-OR operation on the decompressed data to produce resultant data; and a recompression unit to compress the resultant data to produce a further compressed data stream.

Abstract: A method and system for applying pipeline architecture to discrete cosine transform and inverse discrete cosine transform. Each of the discrete cosine transform and inverse cosine transform are divided into four phases computed by process elements. Each phase can be designed by adjusting the amount of process elements according the demand of performance.

Abstract: Embodiments of the present invention provide a coding system that codes data according to a pair of coding chains. A first coding chain generates coded video data that can be decoded by itself to represent a source video sequence of a small size, such as a size sufficient to support the real time playback and display features of a video editing application. The second coding chain generates coded video data representing supplementary data, which when decoded in conjunction with the coded video data of the first coding chain, yields the source video sequence for full-size display. The output of the first coding chain may be stored in memory in a file structure that can be accessed independently of the second chain's output and, therefore, it facilitates real time decoding and playback.

Abstract: Disclosed is a variable-length image compression arrangement which represents successive distinct image data values (220, 221) of an image using corresponding non-decreasing Palette values (215, 222), and which incorporates (915, 1025) into the encoded data stream information recording the position in the encoded data stream at which each Palette value bit representation length increase occurs.

Abstract: A method for representing video data related to a macroblock of a video image in a coding procedure wherein certain, video data or combinations of video data is represented in predefined events associated with indexed positions in a Variable Length Code (VLC) table including codes assigned to each indexed position, including: determining, with a processor, that a first event among said predefined events occurs during the coding procedure; coding, with the processor, the first event with a code assigned to a position x in the VLC table being associated with the first event, the VLC table being stored in a memory device; determining, with the processor, whether x>0, wherein 0 denotes a position at a top of the VLC table; and rearranging, with the processor, the VLC table by associating a second event currently associated with a position x?1 with the position x, and associating the first event with the position x?1.

Abstract: A coding method for an ordered series of quantized transform coefficients of a block of image data, including a context adaptive position coding process to encode the position of clusters of non-zero-valued coefficients, e.g., a multidimensional position coder that uses one of a plurality of code mappings selected according to at least one criterion including at least one context-based criterion, and an amplitude encoding process to encode any amplitudes remaining to be coded, the amplitude coding using one or a plurality of amplitude code mappings selected according to at least one criterion, including a context-based criterion. A context-based selection criterion is meant a criterion that during encoding is known or derivable from one or more previously encoded items of information. Also a coding apparatus, a decoding apparatus, a computer readable medium configured with instructions that when executed implement a coding method, and another medium for a decoding method.

Abstract: Lossless video data compression is performed in real time at the data rate of incoming real time video data in a process employing a minimum number of computational steps for each video pixel. A first step is to convert each pixel 8-bit byte to a difference byte representing the difference between the pixel and its immediate predecessor in a serialized stream of the pixel bytes. Thus, each 8-bit pixel byte is subtracted from its predecessor. This step reduces the dynamic range of the data. A next step is to discard any carry bits generated in the subtraction process of two's complement arithmetic. This reduces the data by a factor of two. Finally, the 8-bit difference pixel bytes thus produced are subject to a maximum entropy encoding process. Such a maximum entropy encoding process may be referred to as a minimum length encoding process. One example is Huffman encoding.

Abstract: When a plurality of image data are to be compressed, an image correlation information extraction unit extracts respective image correlation information of image data, using first image data as reference image data. An encoding unit compresses the extracted image correlation information to produce encoded data. A data output unit outputs the compressed data and the reference image data to a page memory. When the compressed data are to be restored, a data input unit supplies the image correlation data input from the page memory to an image correlation information decoding unit, and supplies the reference image data to an image restoring unit. The image correlation information decoding unit decodes the image correlation data into the respective image correlation information and supplies the image correlation information to the image restoring unit. The image restoring unit restores the plural image data from the respective image correlation information and the reference image data.

Abstract: An image data compressing apparatus includes an image data compressor for compressing image data input thereto at first and second compression rates to produce first and second compressed data, respectively, an approximate-expression selector having an approximate-expression table including approximate expressions corresponding to sample data sizes, respectively, and a compression rate determining unit for determining the second compression rate. The approximate-expression selector selects an approximate expression from the approximate expressions. The first approximate expression corresponds to a first sample data size nearest a data size of the first compressed data among the sample data sizes. Each of the approximate expressions indicates a change of a data size in response to a compression rate. The compression rate determining unit determines the second compression rate based on the selected approximate expression.

Abstract: A method for compressing image data is used to process image data. The method includes the following steps as sampling pixels expressing an image, transforming the sampling data into transformed data by forward discrete cosine transformation, quantifying the transformed data according to a quantification table into quantified data, encoding the quantified data according to Huffman table, and generating a frame data. When the frame data is processed along the reverse pipeline, the frame data is decompressed to the image data.

Abstract: There is provided a H.264 decoding method for fast CAVLC, which searches multiple tables effectively and fast to obtain coefficients for CAVLC blocks within the shortest period of time such that a decoder with excellent efficiency can be designed for low frequency. The H.264 decoding method for fast CAVLC includes: a first step of obtaining the number of ‘0’s including the firstly inputted bit ‘0’ to the bit ‘0’ right before the bit ‘1’ firstly appearing to obtain a row index value; a second step of obtaining a fix index indicating the first bit ‘1’; a third step of obtaining a column index indicating a bit stream other than the row index and fix index; and a fourth step of obtaining a total coefficient and trailing ones T1s corresponding to the row index value and the column index value.

Abstract: A method comprises determining a plurality of time intervals Tp and Tn within a variable bit rate (VBR) representation of an image sequence. The time intervals Tp are those in which a number of blocks of information per unit time is greater than a baseline value. The time intervals Tn are those in which a number of blocks of information per unit time is less than the baseline value. A second representation of the image sequence is created in which some blocks of information Bp are removed from the time intervals Tp and interlaced with blocks of information Bn in the time intervals Tn to reduce a variation in a number of blocks of information per unit time between the time intervals Tp and Tn.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: A flag indicating whether a decoding process is completed or continued is disposed in each of entries of a decoding process table. A decoded value and a significant bit length are recorded in the entry of a decoding process completion. Information for identifying the decoding process table which is used in a subsequent process, and a bit length that is clipped from a code word which is used when referring to a subsequent table are recorded in the entry of the decoding process continuation. When the decoding process starts, the information for identifying the table to be used and the bit length that is referred to from the code word when referring to the table are designated together with the code word. The decoding process table reference is repeated as the occasion demands. With the above configuration, there is provided a variable length code decoding device.

Abstract: One embodiment of the invention is directed to a printer that is configured to interleave color plane data. The interleaved data is compressed, thereby forming compressed data having runs, seedrow copies and literals. In the compression process, commands are buffered to enable independent and simultaneous operation of a run module, a seedrow copy module and a literal module used in forming the compressed data.

Abstract: An inputted digital signal of a first format (DV video signal) is restored to a variable-length code by having its framing cancelled by a de-framing section 11, then decoded by a variable-length decoding (VLD) section 12, inversely quantized by an inverse quantizing (IQ) section 13, and inversely weighted by an inverse weighting (IW) section 14. Then, required resolution conversion in the orthogonal transform domain (frequency domain) is carried out on the inversely weighted video signal by a resolution converting section 16. After that, the video signal having the resolution converted is weighted by a weighting (W) section 18, then quantized by a quantizing (Q) section 19, coded by variable-length coding by a variable-length coding (VLC) section 20, and outputted as a digital signal of a second format (MPEG video signal).

Abstract: An image processing apparatus includes a decompressing unit decompressing image data having a first data compression format, an obtaining unit obtaining a second data compression format that is applicable for decompression by another image processing apparatus, a re-compressing unit re-compressing the decompressed image data with the second data compression format obtained by the obtaining unit, and a transmitting unit transmitting the re-compressed image data to the other image processing apparatus.

Abstract: An image representation format for representing a digital image comprises: image information stored as a bitstream representing sequential image blocks, each block comprising one or more components, each component comprising one or more data units and each data unit being represented as a Huffman-coded stream of coefficients of basis functions, wherein a zeroth order coefficient is represented as a difference to the previous zeroth order coefficient of the corresponding component, and a block information table, which comprises: indicators to the first coefficient of a specified order of each image block in said bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of said specified order of the image block, and the zeroth order coefficient of at least the first data unit of each component, said zeroth order coefficient being represented in a non-differential form.

Abstract: An image representation format for representing a digital image comprises: image information stored as a bitstream representing sequential image blocks, each block comprising one or more components, each component comprising one or more data units and each data unit being represented as a Huffman-coded stream of coefficients of basis functions, wherein a zeroth order coefficient is represented as a difference to the previous zeroth order coefficient of the corresponding component, and a block information table, which comprises: indicators to the first coefficient of a specified order of each image block in said bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of said specified order of the image block, and the zeroth order coefficient of at least the first data unit of each component, said zeroth order coefficient being represented in a non-differential form.

Abstract: A VSB communication system or transmitter for processing supplemental data packets with MPEG-II data packets includes a VSB supplemental data processor and a VSB transmission system. The VSB supplemental data processor includes a Reed-Solomon coder for coding the supplemental data to be transmitted, a null sequence inserter for inserting a null sequence to an interleaved supplemental data for generating a predefined sequence, a header inserter for inserting an MPEG header to the supplemental data having the null sequence inserted therein, a multiplexer for multiplexing an MPEG data coded with the supplemental data having the MPEG header added thereto in a preset multiplexing ratio and units. The output of the multiplexer is provided to an 8T-VSB transmission system for modulating a data field from the multiplexer and transmitting the modulated data field to a VSB reception system.

Abstract: An image decoding device for decoding a hierarchically encoded compressed code obtained by dividing an image into a plurality of tiles and performing discrete wavelet transform on the pixel values of the image tile by tile includes a tile boundary smoothing part that performs smoothing of tile boundary distortion on the image after the decoding by application of a low-pass filter. The tile boundary smoothing part controls the degree of smoothing of the low-pass filter according to the ratio of the decoding quantity to the entire quantity of the compressed code. The decoding quantity is the portion of the compressed code which portion is to be decoded.

Abstract: An image representation format for representing a digital image comprises: image information stored as a bitstream representing sequential image blocks, each block comprising one or more components, each component comprising one or more data units and each data unit being represented as a Huffman-coded stream of coefficients of basis functions, wherein a zeroth order coefficient is represented as a difference to the previous zeroth order coefficient of the corresponding component, and a block information table, which comprises: indicators to the first coefficient of a specified order of each image block in said bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of said specified order of the image block, and the zeroth order coefficient of at least the first data unit of each component, said zeroth order coefficient being represented in a non-differential form.

Abstract: An image representation format for representing a digital image comprises: image information stored as a bitstream representing sequential image blocks, each block comprising one or more components, each component comprising one or more data units and each data unit being represented as a Huffman-coded stream of coefficients of basis functions, wherein a zeroth order coefficient is represented as a difference to the previous zeroth order coefficient of the corresponding component, and a block information table, which comprises: indicators to the first coefficient of a specified order of each image block in said bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of said specified order of the image block, and the zeroth order coefficient of at least the first data unit of each component, said zeroth order coefficient being represented in a non-differential form.

Abstract: Embodiments of the present invention provide a coding system that codes data according to a pair of coding chains. A first coding chain generates coded video data that can be decoded by itself to represent a source video sequence of a small size, such as a size sufficient to support the real time playback and display features of a video editing application. The second coding chain generates coded video data representing supplementary data, which when decoded in conjunction with the coded video data of the first coding chain, yields the source video sequence for full-size display. The output of the first coding chain may be stored in memory in a file structure that can be accessed independently of the second chain's output and, therefore, it facilitates real time decoding and playback.

Abstract: A process for improved, lossless data transformation with options for adaptive compression, multidimensional prediction, multi-symbol decoding.

Abstract: A coding method, apparatus, and medium with software encoded thereon to implement a coding method. The coding method includes encoding cluster of consecutive non-zero-valued coefficients, the encoding of a cluster including jointly encoding joint events that each are defined by at least two parameters: the number of zero-valued coefficients preceding the cluster, and the number of non-zero-valued coefficients in the cluster. The encoding of the cluster also includes encoding a parameter indicative of the number of amplitude-1 trailing non-zero-valued coefficients in the cluster, in one version with the parameter indicative of the number of trailing amplitude-1 coefficients part of the joint events such that the coding is according to a 3-dimensional joint variable length coding table. The method further includes encoding the amplitudes of the non-zero-valued coefficients that are not encoded by the joint encoding, e.g., encoding the amplitudes of the other than the trailing amplitude-1 coefficients.

Abstract: A system, method and computer program product having optimal matching to a known or measured probability distribution encodes data without the use of an excessively large lookup table. An encoder constructed according to the present invention uses two or more different encoding methods in combination. In one embodiment, Huffman coding by table lookup is combined with computational generation, such as by using an exponential Golomb equation. The most commonly occurring elements are looked up in a small Huffman table, while the remaining elements are coded with the equation. In another embodiment, data is encoded using two or more equations. In yet another embodiment, data is encoded using multiple tables in conjunction with one or more equations.

Abstract: A method for processing a variable length code comprising: determining a first address; decoding opcodes from the at least one table starting at a first address; in response to each of the opcodes: receiving a portion of a sequence of bits, the sequence of bits comprising a first variable length code; receiving S from the second table at the current address; flushing S bits in the sequence of bits; receiving T corresponding to one of the stages; determining a value of a set of T bits in the sequence of bits; receiving D from the second table at the current address; and computing the next address, the next address being the sum of the current address, D, and the value of the set of T bits; and retrieving the next opcode, the next opcode being retrieved from the next address; and determining the decoded syntax element.

Abstract: An approach to decoding Huffman symbols in JPEG images is described. One approach involves a method of decoding Huffman codes in a JPEG image file. This method involves obtaining a bitstream sample from a bitstream associated with the JPEG image file. The bitstream sample is compared against a threshold value, to identify a Huffman group number. Information associated with a Huffman group is retrieved, and used to extract the current Huffman symbol from the bitstream. A corresponding symbol value can then be obtained, using the current Huffman symbol and the group information.

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 method comprises determining a plurality of time intervals Tp and Tn within a variable bit rate (VBR) representation of an image sequence. The time intervals Tp are those in which a number of blocks of information per unit time is greater than a baseline value. The time intervals Tn are those in which a number of blocks of information per unit time is less than the baseline value. A second representation of the image sequence is created in which some blocks of information Bp are removed from the time intervals Tp and interlaced with blocks of information Bn in the time intervals Tn to reduce a variation in a number of blocks of information per unit time between the time intervals Tp and Tn.

Abstract: A system of image compression is disclosed. The system comprises a first encoder, a second encoder and a determining device. The determining device further comprises a quality lost calculator, a code length expense calculator and a selector. The first encoder generates a first coded data. The second encoder generates a second coded data. Next, the quality lost calculator calculates quality lost values of the first coded data and the second coded data. The code length expense calculator calculates code length expense of the first coded data and the second coded data. Finally, the selector calculates total expense values of the first coded data and the second coded data and selectively outputs one of the first coded data and the second coded data according to the total expense values of the first coded data and the second coded data.

Abstract: Variable bit size run length encoding (“RLE”) is used to encode uninterrupted runs of adjacent first symbols and adjacent second symbols within a sequence that may represent an image. The symbols may be 1s and 0s. The bit size used to encode a run length for a current run is varied in dependence on the bit sized used or required to encode a run length of a previous run of the same symbol type. Further, an image to be encoded may be transformed into an image/bit sequence representing changes from line to line in the image. By so transforming the image, the correlation from run length to run length of like colors is increased, thereby improving the efficiency of the variable bit size RLE.

Abstract: A method of losslessly compressing and encoding signals representing image information is claimed. A lossy compressed data file and a residual compressed data file are generated. When the lossy compressed data file and the residual compressed data file are combined, a lossless data file that is substantially identical to the original data file is created.

Abstract: An image representation format for representing a digital image comprises: image information stored as a bitstream representing sequential image blocks, each block comprising one or more components, each component comprising one or more data units and each data unit being represented as a Huffman-coded stream of coefficients of basis functions, wherein a zeroth order coefficient is represented as a difference to the previous zeroth order coefficient of the corresponding component, and a block information table, which comprises: indicators to the first coefficient of a specified order of each image block in said bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of said specified order of the image block, and the zeroth order coefficient of at least the first data unit of each components said zeroth order coefficient being represented in a non-differential form.

Abstract: An adaptive variable-length coding/decoding method performs an optimal variable-length coding and decoding depending on an intra mode/inter mode condition, quantization step size and a current zigzag scanning position, such that a plurality of variable-length coding tables having different patterns of a regular region and an escape region according to statistical characteristics of the run level data are set. One of the variable-length coding tables is selected according to mode, quantization step size and scanning position, and the orthogonal transform coefficients according to the selected variable-length coding table are variable-length-coded.

Abstract: An adaptive variable-length coding/decoding method performs an optimal variable-length coding and decoding depending on an intra mode/inter mode condition, quantization step size and a current zigzag scanning position, such that a plurality of variable-length coding tables having different patterns of a regular region and an escape region according to statistical characteristics of the run level data are set. One of the variable-length coding tables is selected according to mode, quantization step size and scanning position, and the orthogonal transform coefficients according to the selected variable-length coding table are variable-length-coded.

Abstract: An adaptive variable-length coding/decoding method performs an optimal variable-length coding and decoding depending on an intra mode/inter mode condition, quantization step size and a current zigzag scanning position, such that a plurality of variable-length coding tables having different patterns of a regular region and an escape region according to statistical characteristics of the run level data are set. One of the variable-length coding tables is selected according to mode, quantization step size and scanning position, and the orthogonal transform coefficients according to the selected variable-length coding table are variable-length-coded.