Abstract: A variable length code decoding device for decoding variable length code data, including: a table memory that stores a plurality of decoding process tables having a reference relationship therein; and a decoding control unit that is given a start address and an initial reference bit length of the table memory; and sequentially selects the decoding process tables according to the decoded data to control a process of decoding the variable length code data, wherein when referring to the decoding process table to perform an initial decoding of the variable length code data, the initial decoding process is conducted by a longer bit length to be clipped from the variable length code data for referring to the decoding process table than the bit length used when referring to the other portions of the decoding process table.

Abstract: A decoding method comprising the following steps is provided. The mth lookup index for a new lookup table is obtained according to the number of leading 1's in the bit stream. The nth base Huffman code in a simplified Huffman table is obtained according to the mth lookup index. The (n+1) most significant bits (MSB) are obtained from the bit stream according to the nth base Huffman code. A difference is generated according to the (n+1) MSBs in the bit stream and the nth base Huffman code. Whether the difference is less than 0 is checked. If yes, a symbol index is generated according to the difference and the nth base symbol index, and a symbol is obtained according to the symbol index. If no, n is decreased or increased by 1 according to the method being used, and the data in the simplified Huffman table is compared continually.

Abstract: An image representation format for representing a digital image including 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 the bitstream, information indicating the number of bits in the bitstream between adjacent coefficients of the specified order of the image block, and the zeroth order coefficient of at least the first data unit of each component, the zeroth order coefficient being represented in a non-differential form.

Abstract: An encryption-enabled entropy coder for a multimedia codec is disclosed. The entropy coder implements a randomized Huffman coding scheme without storing multiple sets of Huffman tables in a ROM. The entropy coder includes a ROM storing a single set of code tables, a table lookup section coupled to the ROM which converts symbols to original codewords and vice versa by performing table lookup, and a table randomizer section for converting original Huffman codewords to randomized Huffman codewords and vice versa using an isomorphic code generator algorithm. The table randomizer section performs the conversion based on a key hopping sequence generated by a pseudorandom bit generator using an encryption/decryption key.

Abstract: Methods and apparatus, including computer program products, for generating a data stream encoded by means of a Variable Length Coding scheme. Code words for a data stream including a plurality of code words are encoded in accordance with a Variable Length Coding scheme. A separation marker is inserted between encoded data blocks in the data stream.

Abstract: A method includes receiving, at a decoding device, first contents of a buffer, where the first contents of the buffer include at least a first data symbol. The first data symbol is coded into the first contents of the buffer based at least in part on a first radix of the first data symbol. The first data symbol is decoded from the first contents of the buffer. Based at least in part on the first radix of the first data symbol, it is determined whether the first contents of the buffer include a second data symbol. The second data symbol is decoded from the first contents of the buffer if the first contents include the second data symbol.

Abstract: An audio encoder performs entropy encoding of audio data. For example, an audio encoder determines whether a first code table in a group of plural code tables contains a code representing a first vector. If it does, the code is used, and otherwise the escape code from the first code table is used and the first vector is encoded using, at least in part, a second code table. An audio decoder performs corresponding entropy decoding.

Abstract: Converting a mask constraint into a bitset constraint. For example, a method of converting a mask constraint into a bitset constraint may include determining an intermediate bitset based on a variable-bit component of the mask constraint; and generating the bitset constraint based on the intermediate bitset and on a fixed-bit component of the mask constraint. Other embodiments are described and claimed.

Abstract: A novel and useful method of constructing a fast approximation of a dynamic Huffman table from a data sample comprising a subset of data to be compressed. The frequency of incidence of each symbol in the sample is calculated, and the symbols are then allocated to predefined bins based on their frequency of incidence. The bins are then transformed into binary sub-trees, where the leaf nodes of the binary sub-trees comprise the symbols of the bin associated with the binary sub-trees. The binary sub-trees are then combined via nesting, thereby creating a coarse grained binary tree, where all leaves are mapped to a specified number of depths. The coarse grained binary tree is then traversed, thereby yielding a canonical code for each symbol, thereby defining the entries for a dynamic Huffman table.

Abstract: The invention relates to a method for determining where a next data unit of a bit stream of an image starts. The method comprises analyzing a first part of a bit stream entry, the bit stream entry being included in a data unit, determining from said analysis of the first part of the bit stream entry the number of bits used by the bit stream entry, skipping the number of bits determined to be used by the bit stream entry, and determining if an end of block symbol has been reached, if an end of block symbol has not been reached then a new bit stream entry starting at the end of the previous is analyzed.

Abstract: An audio encoder performs entropy encoding of audio data. For example, an audio encoder determines a Huffman code from a Huffman code table to use for encoding a vector of audio data symbols, where the determining is based on a sum of values of the audio data symbols. An audio decoder performs corresponding entropy decoding.

Abstract: A novel and useful method of constructing a fast approximation of a dynamic Huffman table from a data sample comprising a subset of data to be compressed. The frequency of incidence of each symbol in the sample is calculated, and the symbols are then allocated to predefined bins based on their frequency of incidence. The bins are then transformed into binary sub-trees, where the leaf nodes of the binary sub-trees comprise the symbols of the bin associated with the binary sub-trees. The binary sub-trees are then combined via nesting, thereby creating a coarse grained binary tree, where all leaves are mapped to a specified number of depths. The coarse grained binary tree is then traversed, thereby yielding a canonical code for each symbol, thereby defining the entries for a dynamic Huffman table.

Abstract: In one embodiment of the invention, a method of generating a compressed configuration bitstream for a programmable logic device comprises encoding the most-prevalent data word within the configuration data of the bitstream into a codeword of a first type; encoding a set of more-prevalent data words within the configuration data into codewords of a second type; and including in the compressed bitstream at least some of the data words that are members of the set of more-prevalent data words. The included data words, when received by the programmable logic device, are adapted to be identified by the device as members of the set of more-prevalent data words. The included data words are stored for selection by the device when a codeword of the second type representing an included data word is received by the device.

Abstract: An apparatus for processing variable length coded data includes a coefficient buffer unit and several lookup tables. The coefficient buffer unit includes a coefficient memory and an index register for storing an indication of a non-zero nature of coefficients stored in the coefficient memory. Advantageously, the lookup tables may be altered to adapt the apparatus for processing variable length coded data to handle encoding or decoding video adhering to a specific standard. Furthermore, the lookup tables may be adapted to accelerate the determination of the presence of escape codes and the subsequent handling of the escape codes.

Abstract: A method and system are provided for encoding a plurality of integers with variable-length code tables constructed by combining a plurality of structured code tables. Each code table has an associated set of integer values; the sets are disjoint and exhaustive, so that every integer appears in exactly one set. An integer is encoded using the codebook associated with the set in which the integer appears.

Abstract: A fast data compression method approximating dynamic Huffman coding for applications with exteremely large data sets is disclosed. The method includes periodic regeneration of the Huffman coding tables and use of precomputed information to speed up encoding and decoding.

Abstract: Control of signal compression is coordinated by selectively modifying control parameters affecting the bit rate, sample rate, dynamic range and compression operations. Selected control parameters are modified according to a control function. The control function can include a ratio parameter that indicates the relative or proportional amounts of change to the control parameters. Alternatively, the control function can be represented in a lookup table with values for the selected control parameters related by the control function. Downsampling the input signal samples according to a sample rate control parameter is followed by upsampling to the original sample rate. Errors are calculated between the upsampled and original signal samples. Encoding of the downsampled signal samples and the error samples is performed in accordance with a compression control parameter. The sample rate control parameter and compression control parameter are determined based on the control function.

Abstract: The present invention is based on the finding that an efficient code for encoding information values can be derived, when two or more information values are grouped in a tuple in a tuple order and when an encoding rule is used, that assigns the same code word to tuples having identical information values in different orders and that does derive an order information, indicating the tuple order, and when the code word is output in association with the order information.

Abstract: Provided are a method and an apparatus for selectively encoding/decoding point sequences to maximize bit efficiency of a lightweight application scene representation (LASeR) binary stream. The point sequence encoding method includes the steps of: for each point sequence, (a) selecting one of exponential-Golomb (EG) encoding and fixed length (FL) encoding schemes; (b) when the FL encoding scheme is selected, encoding the point sequence using the FL encoding scheme to generate a binary stream; and (c) when the EG encoding scheme is selected, encoding the point sequence using the EG encoding scheme to generate a binary stream. The binary stream includes a flag indicating which encoding scheme is selected and a parameter k, with which the EG encoding can be most effectively performed, when the EG encoding scheme is selected. According to the encoding method, LASeR point sequences can be efficiently encoded and, during a decoding process, a large overhead is not incurred to a decoder (terminal).

Abstract: An information handling system includes a processor that may perform decoding of a variable-length code (VLC) bitstream after preprocessing the bitstream. The bitstream includes multiple VLC symbols as binary codewords. The processor analyzes incoming VLC bitstream information and generates VLC codeword symbol information in conformance with a VLC lookup table. The processor may access a 2 dimensional VLC lookup table in real time or on-the-fly. The VLC lookup table may reside in a system memory of the IHS. The single VLC lookup table may exhibit two dimensional indexing by leading zero count and bit-length possibility.

Abstract: Methods and apparatus for iteratively encoding a portion of a signal are described in which the portion of the signal is quantised and an output bit count is estimated based on the sum of logarithms to base n of values of each sample in the plurality of quantised samples and the total number of samples. The output bit count corresponds to an estimate of the output bit count for the portion of the signal once encoded using a code, such as a Huffman code.

Abstract: A method for decoding an input bit stream encoded using Huffman encoding generates a lookup table using a standard Huffman code book. Thereafter, at least three bits are extracted from the input bit stream. The at least three bits extracted are used to traverse the lookup table. Subsequently, a data set corresponding to a Huffman code word is accessed, thereby decoding the input bit stream.

Abstract: System and method for decompressing data. A compressed data stream including contiguous variable length data blocks is received, each variable length data block including multiple contiguous variable length data fields. A current data block of the contiguous variable length data blocks is stored in one or more registers of a processor. Decoding state information is stored in another register of the processor. A single machine instruction of the processor is loaded. The instruction includes one or more operands corresponding respectively to the one or more registers, and another operand corresponding to the other register, where the other register is further operable as a destination register to store a result of the machine instruction. The instruction is executed to decompress the current data block using the stored decoding state information, including storing the decompressed current data block in the other register. The decompression is repeated for subsequent blocks in the stream.

Abstract: An adaptive canonical Huffman decoder including a symbol index generator, a content selector, and a symbol table buffer circuit is illustrated. The content selector outputs a content selection signal. The symbol table buffer circuit reads a corresponding symbol table from a plurality of symbol tables stored in an external memory according to the content selection signal and stores the corresponding symbol table. The symbol index generator stores decoding information of a plurality of encoding tables and selects a corresponding decoding information among all the decoding information according to the content selection signal. Then, the symbol index generator receives a bit stream and decodes the bit stream according to the corresponding decoding information to obtain a symbol index. After that, the symbol table buffer circuit obtains an output symbol from the corresponding symbol table according to the symbol index.

Abstract: A method and system for decompressing dynamic Huffman coded bit streams is disclosed.

Abstract: A fast data compression method approximating dynamic Huffman coding for applications with exteremely large data sets is disclosed. The method includes periodic regeneration of the Huffman coding tables and use of precomputed information to speed up encoding and decoding.

Abstract: The method compresses image data into a fixed sized memory. The image is encoded in scans, where the scans are ordered from a perceptually most significant scan to a perceptually least significant scan. The scans also have an attribute 210 determining whether a scan is active or inactive. The method comprises an encoding, transferring and setting step. The encoding step 326, 348 encodes active scans of image data into scan bit-stream data. The transferring step 330, 352 transfers the encoded scan bit-stream data to the fixed size memory. The setting step 452 sets, if the fixed size memory becomes full, the attribute of a perceptually least significant scan to inactive.

Abstract: An improved decoding process as applied to MPEG AAC decoders of the type that use codebooks, reduces redundant traversing steps while finding the location of a specific binary stream codeword in the codebook. To this end, the codebooks are divided into a plurality of node-tables, each table corresponding to a node. From the number of bits “k” in a given node-table, the decimal value of the first “k” bits in a binary stream to be decoded is ascertained and compared with the decimal value of the maximum code word in the given node-table. The comparison is used for the identification of the location of the codeword in the node-tables to assist in decoding without unnecessary traversing of all the nodes in the codebook.

Abstract: Bit-stream Huffman coding may be used for data compression to quickly and efficiently compress relatively small and large datasets. A symbol used in data compression may not be a byte or 8 bits. Rather it has any number of bits. For a certain dataset, a symbol has a dynamic number of bits according to the data size. A symbol may have less than 8 bits for a small dataset, or more than 8 bits for a large dataset. For rapid processing, a large dataset may be broken into smaller datasets that are fast encoded in parallel. Accordingly, the Huffman encoding inputs from a bit-stream instead of a conventional byte-stream and outputs a bit-stream. In particular, bit-stream Static and Adaptive Huffman codings are presented with extended algorithms. Hardware implementation with parallel Huffman encoders and decoders is also illustrated for fast network data compression.

Abstract: The present invention relates to a data compression and decompression system and method for lossless compressing digital data. In one preferred embodiment, the method for handling a data stream having a number of data objects comprising a step of performing a compressing process on a data object based on a compression based value to obtain at least one compressed data result, wherein the data object is considered as one numerical value. The device for handling the data stream comprising a compression means for compressing the data objects according to a compression base value. In another preferred embodiment, the method for handling data having a number of data objects comprising a step of performing a compressing process on a data object by obtaining a compression code for the data object according to a compression coding table, wherein the data object is considered as one numerical value.

Abstract: Entropy coding and decoding techniques are described, which may be implemented separately or in combination. For example, a video encoder uses two-layer run level coding to reduce bitrate for frequency transform coefficients in a quick and efficient manner, and a video decoder uses corresponding two-layer run level decoding. This two-layer coding/decoding can be generalized to more than two layers of run level coding/decoding. The video encoder and decoder exploit common patterns in run level information to reduce code table size and create opportunities for early termination of decoding. Using zoned Huffman code tables helps limit overall table size while still providing a level of adaptivity in encoding and decoding. Using embedded Huffman code tables allows the encoder and decoder to reuse codes for 8×8, 8×4, 4×8, and 4×4 blocks.

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 coding apparatus provides a run-length encoding unit RLE1 that subjects quantized coefficients which are obtained by quantizing frequency components of an image signal to a variable length coding process by using a run value Run that indicates the number of successive zero coefficients and a level value Lev that indicates a value of a non-zero coefficient following the zero coefficients. The run-length encoding unit RLE1 includes a reordering unit Lreodr for reordering level values Lev; a variable length coder LVLC for coding reordered level values ROLev by using a code table that is selected according to the value of a quantization parameter QP; a reordering unit Rreodr for reordering run values Run from high frequency component of the quantized coefficients to low frequency component; and a variable length coder RVLC for coding reordered run values RORun by using a code table that is selected according to the number of already-processed run values.

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: The present invention relates to a method, computer program product and system for the compression of a probability table and the reconstruction of one or more probability elements using the compressed data and method. After determining a probability table that is to be compressed, the probability table is compressed using a first probability table compression method, wherein the probability table compression method creates a first compressed probability table. The first compressed probability table contains a plurality of probability elements. Further, the probability table is compressed using a second probability table compression method, wherein the probability table compression method creates a second compressed probability table. The second compressed probability table containing a plurality of probability elements.

Abstract: A serial transmission controller, a serial transmission decoder and a serial transmission method thereof are disclosed. First, a current address and an access address are compared to select one of a plurality of transmission address modes as an access address mode and then to produce corresponding address information. The transmission address modes use different bits to transmit the address information respectively. According to the access address mode, an access command is selected from a serial command set. Finally, the access command and the address information are transmitted to a serial interface serially. After the access command is encoded to different length of bits, the encoded access command is transmitted to the serial interface so as to reduce the transmission bits and improve the transmission efficiency.

Abstract: In a communication system, Huffman coding techniques are used to obtain shaping gains for an improvement in data transmission rates. More particularly, a novel method of Huffman shaping is described that achieves a shaping gain of greater than 1 dB. The shaping gain results in a higher data rate transmission in a communication system where transmitted power is constrained.

Abstract: A computer-readable recording medium stores therein an information processing program that causes a computer to execute storing an aggregate of layers of nodes respectively having a pointer to an upper node, pointers to a leaf and/or a lower node and branches to lower nodes; obtaining a totaling result of appearance frequencies of character codes described in a file; classifying the character codes by layer, based on appearance probabilities thereof and the totaling result; calculating, based on a quantity of character codes in an ith layer and for the ith layer, a quantity of pointers pointing to leaves, and based on the quantity calculated and for the ith layer, further calculating a number of times nodes are used and a quantity of pointers pointing to lower nodes; generating, based on calculation results, a Huffman tree; and converting the Huffman tree into a node-less Huffman tree and storing the node-less Huffman tree.

Abstract: Embodiments described herein may include example embodiments of a method, article and apparatus for compressing data utilizing combinatorial coding with specified occurrences which may be used for communicating between two or more components connected to an interconnection medium (e.g., a bus) within a single computer or digital data processing system, and/or for communication between computing platforms via a network or other interconnection medium.

Abstract: Embodiments described herein may include example embodiments of a method, article and apparatus for compressing data utilizing adaptive combinatorial encoding with either specified occurrences or specified data length which may be used for communicating between two or more components connected to an interconnection medium (e.g., a bus) within a single computer or digital data processing system, and/or for communication between computing platforms via a network or other interconnection medium.

Abstract: Embodiments described herein may include example embodiments of a method, article and apparatus for compressing data utilizing combinatorial coding with specified occurrences which may be used for communicating between two or more components connected to an interconnection medium (e.g., a bus) within a single computer or digital data processing system, and/or for communication between computing platforms via a network or other interconnection medium.

Abstract: A method and apparatus for compressing data is described. In one embodiment, a processor receives one or more strings of data to be compressed. Duplicate strings are replaced with pointers using a first compression algorithm. An output of the first compression algorithm is processed with a second compression algorithm using a variable context dynamic encoder to generate a tree of non-overlapping bit-sequences where the length of each sequence is being inversely proportional of the likelihood of that symbol needing to be encoded. Unused symbols are not generated on the tree.

Abstract: A decoder for decoding a message using an arbitrary-side growing (ASG) Huffman tree including a plurality of codewords and symbols includes a database, a processing module, and a bit pattern matching module. The database stores a plurality of parameters corresponding to the ASG Huffman tree divided into several sub-trees according to a Hashemian cut operation and a bits-pattern-Xor (BPX) operation. The plurality of parameters include a bit pattern of a sub-tree of the ASG Huffman tree divided according to the BPX operation and a code length of the bit pattern. The processing module receives a bit stream corresponding to the ASG Huffman tree from an encoder. The bit pattern matching module selects bits from the bit stream according to the code length of the bit pattern and decodes the selected bits into a symbol in the ASG Huffman tree by comparing the selected bits with the bit pattern.

Abstract: A method for transcoding between video streams using different entropy coding, comprising the steps of (A) decoding a first video stream using a first set of entropy codes, and (B) generating a second video stream by entropy encoding the decoded first video stream using a second set of entropy codes. The first set of entropy codes and the second set of entropy codes are configured to represent all valid coefficient values of the first video stream.

Abstract: A system for the context-based for the context-based encoding of an input signal includes a domain transform module and a context-based coding module. The domain transform module is operable to convert the input signal into a sequence of transform coefficients c[i]. The context-based coding module includes a bit-plane scanning module, and context modeling module, and a statistical encoding module. The bit-plane scanning module is operable to produce a bit-plane symbol bps [i,bp] for each transform coefficient c[i] and each bit-plane [bp]. The context modeling module is operable to assign one or more context values to each of the received bit plane symbols bps [i,bp]. The statistical coding module is operable to code each of the bit plane symbols bps [i,bp] as a function of one or more of the corresponding context values to produce a context-based encoded symbol stream.

Abstract: Methods and apparatus, including computer program products, for generating a data stream encoded by means of a Variable Length Coding scheme. Code words for a data stream including a plurality of code words are encoded in accordance with a Variable Length Coding scheme. A separation marker is inserted between encoded data blocks in the data stream.

Abstract: A decoder for decoding a message using an arbitrary-side growing (ASG) Huffman tree including a plurality of codewords and symbols includes a database, a processing module, and a bit pattern matching module. The database stores a plurality of parameters corresponding to the ASG Huffman tree divided into several sub-trees according to a Hashemian cut operation and a bits-pattern-Xor (BPX) operation. The plurality of parameters include a bit pattern of a sub-tree of the ASG Huffman tree divided according to the BPX operation and a code length of the bit pattern. The processing module receives a bit stream corresponding to the ASG Huffman tree from an encoder. The bit pattern matching module selects bits from the bit stream according to the code length of the bit pattern and decodes the selected bits into a symbol in the ASG Huffman tree by comparing the selected bits with the bit pattern.

Abstract: A method for designing a keyboard for efficient data entry. A user inputs data from a predefined set of characters such as letters or symbols on an input device by pressing one or more keys, in a sequential fashion, for each character. Based on the frequency of occurrence for each character, a prefix-free coding is used to generate an optimal or near-optimal key sequence mapping for the given character set. In one exemplary embodiment, eight to twelve keys from a phone keypad are used to generate English alphabets, which substantially reduces the average number of keystrokes per character. The present invention enables the user to efficiently input typical data from a given probability distribution of characters using a limited number of keys.

Abstract: A method for transcoding between videostreams using different entropy coding, comprising the steps of (A) decoding a first videostream using a first set of entropy codes, and (B) generating a second videostream by entropy encoding the decoded first videostream using a second set of entropy codes. The first set of entropy codes and the second set of entropy codes are configured to represent all valid coefficient values of the first videostream.

Abstract: A decoder for decoding an input bit stream into a plurality of symbols is provided. The decoder includes an extractor, a length generator, a base selector, and a processing unit. The extractor receives the input bit stream and extracts a code with a predetermined codeword length therefrom. The length generator receives the extracted code and determines a first codeword length corresponding to a symbol according to the extracted code and a base table. The base selector determines a codeword base corresponding to the first codeword length according to the base table. The processing unit generates the symbol corresponding to the extracted code according to the codeword base, an offset table and the first codeword length.