568 results about "Arithmetic coding" patented technology

A method, medium, and apparatus encoding and / or decoding an image in order to increase encoding and decoding efficiency by performing binary-arithmetic coding / decoding on a binary value of a syntax element using a probability model having the same syntax element probability value for respective context index information of each of at least two image components.

A video codec for real-time encoding / decoding of digitized video data with high compression efficiency, comprising a frame encoder receiving input frame pixels; a codec setting unit for setting and storing coding setting parameters; a CPU load controller for controlling desired frame encoding time and CPU loading; a rate controller for controlling frame size; a coding statistics memory for storing frequency tables for arithmetic coding of bitstream parameters and a reference frame buffer for storing reference frames. The frame encoder comprises a motion estimation unit, a frame head coding unit, a coded frame reconstruction and storage unit and a macroblock encoding unit. The macroblock encoding unit provides calculation of texture prediction and prediction error, transforming texture prediction error and quantization of transform coefficient, calculation of motion vector prediction and prediction error and arithmetic context modeling for motion vectors, header parameters and transform coefficients. The codec also includes a deblocking unit for processing video data to eliminate blocking effect from restored data encoded at high distortion level, which may be a part of encoder or decoder, an internal resize unit, providing matching downscaling of a frame before encoding and upscaling of decoded frame according to the coding setting parameters, and a noise suppression unit.

A method for encoding a video frame or picture comprises dividing up the video frame or the picture in portions of a first type associated with a first scanning pattern, and portions of a second type associated with a second scanning pattern. Data corresponding to a predetermined of the portions of the video frame or picture is transformed into a two-dimensional transform coefficient array. Fhe transform coefficients are precoded in order to obtain transform data units. One of a first and a second set of context models is chosen depending on as to whether the predetermined portion is a portion of a type being associated with the first or the second scanning pattern. One context model of the chosen one of the first and the second set of context models is assigned to the transform data unit based on the scanning position assigned to the predetermined transform coefficient. Finally, the transform data unit or a sub-unit thereof is arithmetically encoded into a coded bit stream based on the probability estimation with which the assigned context model is associated.

A system and process for broadcast and communication with bi-level or sketch video at extremely low bandwidths is described. Essentially, bi-level and sketch video presents the outlines of the objects in a scene being depicted. Bi-level and sketch video provides a clearer shape, smoother motion, shorter initial latency and cheaper computational cost than do conventional DCT-based video compression methods. This is accomplished by converting each color or gray-scale image frame to bi-level or sketch image frame using adaptive thresholding method, compressing bi-level or sketch image frames into bi-level or sketch video using adaptive context-based arithmetic coding method. Bi-level or sketch video is particularly suitable to such small devices as Pocket PCs and mobile phones that possess small display screen, low bandwidth connection, and light computational power.

A video codec for real-time encoding / decoding of digitized video data with high compression efficiency, comprising a frame encoder receiving input frame pixels; a codec setting unit for setting and storing coding setting parameters; a CPU load controller for controlling desired frame encoding time and CPU loading; a rate controller for controlling frame size; a coding statistics memory for storing frequency tables for arithmetic coding of bitstream parameters and a reference frame buffer for storing reference frames. The frame encoder comprises a motion estimation unit, a frame head coding unit, a coded frame reconstruction and storage unit and a macroblock encoding unit. The macroblock encoding unit provides calculation of texture prediction and prediction error, transforming texture prediction error and quantization of transform coefficient, calculation of motion vector prediction and prediction error and arithmetic context modeling for motion vectors, header parameters and transform coefficients. The codec also includes a deblocking unit for processing video data to eliminate blocking effect from restored data encoded at high distortion level, which may be a part of encoder or decoder, an internal resize unit, providing matching downscaling of a frame before encoding and upscaling of decoded frame according to the coding setting parameters, and a noise suppression unit.

A system and process for broadcast and communication with bi-level or sketch video at extremely low bandwidths is described. Essentially, bi-level and sketch video presents the outlines of the objects in a scene being depicted. Bi-level and sketch video provides a clearer shape, smoother motion, shorter initial latency and cheaper computational cost than do conventional DCT-based video compression methods. This is accomplished by converting each color or gray-scale image frame to bi-level or sketch image frame using adaptive thresholding method, compressing bi-level or sketch image frames into bi-level or sketch video using adaptive context-based arithmetic coding method. Bi-level or sketch video is particularly suitable to such small devices as Pocket PCs and mobile phones that possess small display screen, low bandwidth connection, and light computational power.

Binarization a data value comprises binarizing the minimum of the data value and a predetermined cut-off value in accordance with a first binarization scheme, in order to yield a primary prefix. If the data value is greater than the cut-off value, binarizing a difference of the data value minus the predetermined cut-off value in accordance with a second binarization scheme to obtain a binary suffix, the first binarization scheme being different from the second binarization scheme, and appending the primary suffix to the primary prefix is performed. A very effective compression of data values may be achieve by using the binarization scheme for preparing the syntax elements for the arithmetic coding, the binarization schemes substantially being a combination of two different binarization schemes, and by using binary arithmetic coding instead of m-ary arithmetic coding for coding the binarized syntax elements.

A method for encoding a syntax element contained in a precoded video signal into a coded bit stream, the precoded video signal representing at least one video frame, the syntax element being associated with a predetermined portion of the video frame and being indicative of as to whether the predetermined portion of the video frame is precoded in a first or a second way into the precoded video signal is described. The method comprises investigating as to whether a neighboring portion of the video frame neighboring the predetermined portion is precoded in the first way or the second way, in order to obtain a binary value; assigning one of at least two context models to the predetermined portion of the video frame based on the binary value, wherein each context model is associated with a different probability estimation; and arithmetically encoding the syntax element into the coded bit stream based on the probability estimation with which the assigned context model is associated.

This invention is method of decoding a context based adaptive binary arithmetic encoded bit stream. The invention determines a maximum number of iterations for decoding a next symbol. This preferably employs a left most bit detect command. The invention considers the bit stream bit by bit until detection of a bit having a first digital state of the maximum number of iterations. If the maximum number of iterations occurs first, the invention decodes the considered bits. If a bit having the first digital state occurs first, the invention selects a number of next bits from the bit stream dependent upon the determined position within the coding table and decodes a symbol corresponding to the maximum number of bits and the selected number of next bits. The invention preferably pre-calculates an order symbol contexts corresponding to an order of determination of a code tree encompassing all possible codes and decodes symbols dependent upon a current context within the pre-calculated.

A system and process for broadcast and communication with bi-level or sketch video at extremely low bandwidths is described. Essentially, bi-level and sketch video presents the outlines of the objects in a scene being depicted. Bi-level and sketch video provides a clearer shape, smoother motion, shorter initial latency and cheaper computational cost than do conventional DCT-based video compression methods. This is accomplished by converting each color or gray-scale image frame to bi-level or sketch image frame using adaptive thresholding method, compressing bi-level or sketch image frames into bi-level or sketch video using adaptive context-based arithmetic coding method. Bi-level or sketch video is particularly suitable to such small devices as Pocket PCs and mobile phones that possess small display screen, low bandwidth connection, and light computational power.

Techniques for context-adaptive binary arithmetic coding (CABAC) coding with a reduced number of context coded and / or bypass coded bins are provided. Rather than using only truncated unary binarization for the syntax element representing the delta quantization parameter and context coding all of the resulting bins as in the prior art, a different binarization is used and only part of the resulting bins are context coded, thus reducing the worst case number of context coded bins for this syntax element. Further, binarization techniques for the syntax element representing the remaining actual value of a transform coefficient are provided that restrict the maximum codeword length of this syntax element to 32 bits or less, thus reducing the number of bypass coded bins for this syntax element over the prior art.

An audio encoder performs adaptive entropy encoding of audio data. For example, an audio encoder switches between variable dimension vector Huffman coding of direct levels of quantized audio data and run-level coding of run lengths and levels of quantized audio data. The encoder can use, for example, context-based arithmetic coding for coding run lengths and levels. The encoder can determine when to switch between coding modes by counting consecutive coefficients having a predominant value (e.g., zero). An audio decoder performs corresponding adaptive entropy decoding.

A method of video decoding is provided that includes receiving a data stream comprising a sequence of syntax elements that were compressed using context-adaptive binary arithmetic coding (CABAC), such that the encoding of each bin of a bin string representative of a syntax element was performed by arithmetic encoding. Two consecutive bins of a syntax element are decoded in parallel. Speculative computation and prefetching is used to reduce the critical path and thereby improve processing speed.

A method for encoding a video sequence is provided that includes entropy encoding syntax elements representative of transform coefficients generated as the video sequence is processed, wherein entropy encoding syntax elements representative of a transform coefficient includes binarizing the syntax elements representative of the transform coefficient to generate a plurality of binary symbols (bins), coding a portion of the plurality of bins in context coding mode, and coding a remaining portion of the plurality of bins in bypass coding mode. The method further includes reducing the number of bins that are coded in context coding mode for each transform coefficient in a plurality of subsequent transform coefficients that are entropy encoded after a specified number of transform coefficients have been entropy encoded.

Method and apparatus for image transmission using arithmetic coding, based on continuous error detection uses a controlled amount of added redundancy. A continuous error detection scheme is provided, wherein there is a trade-off between the amount of added redundancy and the time needed to detect an error once it occurs. Herein, there is no need for the cyclic redundancy check (CRC) to wait until an entire block of data has been received and processed before an error can be detected. The invention can be used to great advantage both in the automatic repeat request (ARQ) and other concatenated coding schemes. Errors in the received bit stream are detected by introducing added redundancy, e.g., a forbidden symbol, in the arithmetic coding operation. The forbidden symbol is never intended to be encoded. The redundancy error causes loss of synchronization, which is used to detect errors. If a forbidden symbol gets decoded, it means that an error has occurred. In this invention, there is direct control over the amount of redundancy added vs. the amount of time it takes to detect an error. For image compression systems, by using the invention and ARQ, only one device would suffice both for source compression and channel coding.

Disclosed herein is an arithmetic decoding device including: an arithmetic decoding unit configured to decode coded data resulting from arithmetic coding on a basis of a context variable indicating a probability state and a most probable symbol; a plurality of arithmetic registers configured to supply the context variable to the arithmetic decoding unit and retain a result of operation by the arithmetic decoding unit; and a plurality of save registers configured to save contents retained in the arithmetic registers.

A method for determining a context for coding is disclosed. The method generally includes the steps of (A) generating a plurality of results by examining a prediction mode for each of a plurality of neighbor blocks to a current block in a bitstream for digital video, wherein at least one of the neighbor blocks is subpartitioned, (B) generating a plurality of first variables based on the results and (C) coding the bitstream using a binary arithmetic coding based on a particular context among a plurality of context determined from the first variables.

A method and processor for providing context-based adaptive binary arithmetic CABAC coding. Binarization is performed on one or more syntax elements to obtain a binary sequence. Data bits of the said binary sequence are provided to an arithmetic encoding unit in bulk. Binarization is performed on one or more syntax elements to generate exp Golomb code by converting mapped syntax-element values to corresponding floating point type values. Re-normalization of CABAC encoding is performed by restructuring the re-normalization into two processing units including an arithmetic encoding unit and a bit writing unit. The bit writing unit is configured to format signal bits into a multiple-bit sequence, and write multiple bits simultaneously during an execution of a bit writing loop.