1. A context-based arithmetic encoding apparatus, the apparatus comprising: an N-tuple context determining unit to determine a context of a current N-tuple to be encoded, wherein N is a positive integer; an escape code encoding unit to perform an encoding on an escape code based on the context of the current N-tuple; a Most Significant Bit (MSB) context determining unit to determine an MSB context corresponding to an MSB symbol of the current N-tuple; a probability model mapping unit to determine a probability model using the context of the current N-tuple and the MSB context; an MSB encoding unit to perform an encoding on an MSB based on the determined probability model; and a Least significant Bit (LSB) encoding unit to perform an encoding on an LSB based on a bit depth of the LSB derived from the encoding of the escape code using at least one processor.