Patent ID: 6055338
Filing Date: 2000-04-25
Classification: G06T,H03M,H04N

Abstract:
An encoding apparatus, comprising:a context generator which generates a context for the current symbol using a plurality of reference symbols, located at predetermined positions in a symbol sequence, supplied from an information source;a memory which stores, for each context, state data relating to an arithmetic parameter and a prediction value of the current symbol, in which reading and writing operation can be performed to the memory at the same time;a buffer which temporally stores a plurality of contexts for successively inputted symbols to be encoded;a first comparator which compares the contexts stored in the buffer to each other;a second comparator which compares the prediction value for the current symbol, read from the memory, to the current symbol itself to be actually encoded;an arithmetic encoder which encodes the current symbol and updates the state data and the prediction value of the corresponding context, in accordance with the state data read from the memory and the comparison result of the second comparator; anda controller which controls, in accordance with the comparison result of the first comparator, reading operation of the state data and the prediction value and writing operation of updated state data and updated prediction value to the memory.