35 results about "Context-adaptive variable-length coding" patented technology

Described herein is a context adaptive variable length code decoder for decoding macroblock adaptive field / frame coded video data. In one embodiment, there is presented a context adaptive variable length code decoder. The context adaptive variable length code decoder comprises a symbol decoder, and a left neighbor buffer. The symbol decoder decodes context adaptive variable length code symbols representing frequency coefficients associated with a partition of a macroblock. The left neighbor buffer stores information about another partition, the another partition being a left neighbor of the partition. The information about the another partition is overwritten by information about the partition.

A system and method that process encoded data, wherein the encoded data is an encoded video stream. The encoded data may be buffered and the characteristics of the buffered encoded data may be determined and used to select a decoding table from a plurality of decoding tables. An encoded word may then be decoded using the selected decoding table. The output of the decoding table may be the corresponding decoded word and the size of the encoded word. The size of the encoded word may be utilized to shift the buffered encoded data. The decoded word may be sent to the appropriate portion of the system.

Methods and systems for processing an encoded video stream are disclosed. Aspects of the method may comprise generating a plurality of temporal or spatial prediction pixels based on mode information within the encoded video stream. A plurality of prediction errors may be generated from a plurality of quantized frequency coefficients generated from the encoded video stream. At least one current macroblock may be generated using the generated plurality of temporal or spatial prediction pixels based on the generated plurality of prediction errors. The encoded video stream may be symbol interpreted using context adaptive variable length coding and / or context adaptive binary arithmetic coding. The encoded video stream may be buffered prior to the symbol interpretation. The plurality of quantized frequency coefficients may be generated from the encoded video stream. If the encoded video stream comprises temporal prediction mode information, the plurality of temporal prediction pixels may be generated.

The invention discloses a context-adaptive variable-length coding method and a system thereof. The method comprises the following steps that: a coefficient block that is needed to be coded is mapped as a one-dimensional coefficient array; and according to positional information of all coefficients in the one-dimensional coefficient array, the total number of nonzero coefficients in the one-dimensional coefficient array as well as a position of a first nonzero coefficient and a position of a last nonzero coefficient in the one-dimensional coefficient array are parsed; and with combination of the total number of the nonzero coefficients in the one-dimensional coefficient array, reversed scanning is carried out on all coefficients between the last nonzero coefficient and the first nonzero coefficient in the one-dimensional coefficient array, wherein the last nonzero coefficient and the first nonzero coefficient are contained in all the coefficients, so that coding on an original coefficient block is completed.

The invention belongs to the field of digital video signal encoding and decoding technology, in particular to a hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code. Two methods of code table partition and code combination are used in the method, fourteen run_before codes with each having a value of 0 or two run_before codes not equal to 0 can be decoded at most in one clock period. The input video code stream firstly passes through a preamble 1 detector to detect whether run_before code to be decoded is zero, the preamble 1 detector can detect at most 14 bits of preamble 1 once. When the value of a current run_before code is not zero, if the total number of 0 included before the current decoding position is counted as zerosLeft, the run_before code can be sorted into seven types according to the value of zerosLeft, the run_before code table specified in the original standard is partitioned into seven sub-code tables, the code is decoded for each type. With the method, the data processing capability of the hardware decoder can be greatly increased.

A variable-length coding apparatus which receives image data block by block, and generates coded data from syntax elements. A storage unit temporarily stores the image data, while, at the same time, a first syntax element calculating unit calculates a first syntax element from the image data. A first coding unit generates coded data of the first syntax element from a value of the first syntax element. A second syntax element is calculated from the image data by a second syntax element calculating unit that reads out the image data stored in the storage unit. A second coding unit generates coded data of the second syntax element on the basis of the values of the first and second syntax elements, and a packing unit connects the coded data of the first and second syntax elements.

The invention discloses an entropy decoding device and method for realizing CAVLC (context-based adaptive variable length coding) of H.246. The entropy decoding device comprises a bypath module circuit unit; the bypath module circuit unit for connecting adjacent two stages of decoding modules is used for transmitting decoding parameters obtained by the last-stage decoding module to the next-stage decoding state machine skipping control module and the next-stage decoding module from the bypath module circuit unit; and a CAVLC control module further comprises a parameter transmission control module which is used for controlling to transmit the decoding parameters obtained by the last-stage decoding module to a corresponding decoding parameter register at a decoding state and controlling to transmit the corresponding decoding parameters to the next-stage decoding state machine skipping control module and the next-stage decoding module from the bypath module circuit unit. Due to the adoption of the entropy decoding device and method, the decoding speed is effectively improved.

The invention discloses a decoding method of adaptive variable length coding based on a context and a system of the adaptive variable length coding, wherein the method comprises the steps of obtaining a code stream needing to be decoded; determining the non-zero coefficient number predicted value nC in the code stream; according to the predicated value nC, finding a preset first decoding code table to obtain the number of the non-zero coefficients and the number of the trailing ones in the code stream; if the number of the non-zero coefficients is more than 0 and the number of the tailing ones is more than 0, decoding the symbol of the tailing with 1 coefficients; if the number of the non-zero coefficients is less than the maximum number value of the non-zero coefficients, finding a preset second decoding code table according to the number of the non-zero coefficients, obtaining the number of total zeros before the last non-zero coefficient in the code stream; according to the number of total zeros before the last non-zero coefficient and the number of the non-zero coefficients, decoding the numbers of zeros before other non-zero coefficients in the code stream. By adoption the decoding method and the system disclosed by the invention, the storage space of the code table can be saved and the decoding efficiency can be improved.

Context-adaptive variable length coding (CAVLC) for scalable video coding (SVC) coarse granular scalability (CGS) enhancement layer coding that utilizes the number of coefficients larger than one (NLrg1) as a syntax element. The coding of coeff_token is based on TotalCoeff and NLrg1 values. Levels are adaptively encoded based on NLrg1 syntax element total_zeros is encoded by adaptively selecting VLC tables based on an estimated number of a neighboring blocks' total_zeros.