Arithmetic decoding method and an arithmetic decoding apparatus
AssigneePanasonic Communications Co., Ltd.
InventorHitoshi Horie
Life of this patent
Estimating the term…
Abstract
An arithmetic decoding apparatus is provided that carries out complete pipeline processing. Fluctuations in the pipeline caused by occurrence of the normalization are resolved by using a future-predicted Qe memory. In coding multi-valued images, common contexts are generated without distinguishing between AC and DC components of DCT coefficients.
Claims7
An arithmetic decoding method in which arithmetic decoding is performed in pipeline processing on arithmetic coded data obtained by performing arithmetic coding on orthogonal transformation coefficients of multi-valued data, the method comprising:
- determining whether input arithmetic coded data belongs to a more probable symbol or a less probable symbol on a number line that is divided using a probability estimation value of the more probable symbol and a probability estimation value of the less probable symbol, and outputting, as a decoded symbol, a predicted value of a symbol to which the arithmetic coded data belongs;
- assigning a context, using a context model formed to be common to a DC component and an AC component, to each node of a context tree constructed corresponding to a decision sequence having tree-structured decision events to perform binary decomposition on the orthogonal transformation coefficients in performing arithmetic coding, transiting on the context tree corresponding to a value of the decoded symbol whenever the decoded symbol is generated, and extracting a context assigned to the node of a transition destination;
- and
- estimating a probability estimation value of a less probable symbol, a predicted value of a more probable symbol or the less probable symbol corresponding to the output context to provide to the determining.
An arithmetic decoding apparatus in which arithmetic decoding is performed in pipeline processing on arithmetic coded data obtained by performing arithmetic coding on orthogonal transformation coefficients of multi-valued data, the apparatus comprising:
- an arithmetic decoding calculator which determines whether input arithmetic coded data belongs to a more probable symbol or a less probable symbol on a number line that is divided using a probability estimation value of the more probable symbol and a probability estimation value of the less probable symbol, and outputs, as a decoded symbol, a predicted value of a symbol to which the arithmetic coded data belongs;
- a context generator which has a state transition table in which a state number is registered corresponding to each of decision events used in performing binary decomposition on the orthogonal transformation coefficients in performing arithmetic coding, a context determined for each state number based on a context model common to a DC component and an AC component, and a next state number to which transition proceeds corresponding to a value of a decoded symbol, and generating a context corresponding to the state number whenever a decoded symbol is generated;
- and
- an estimator which estimates a predicted value of a more probable symbol and a probability estimation value of a less probable symbol corresponding to the context output from the context generator to provide to the arithmetic decoding calculator.
Dependencies are inferred from the claim text.