Scalable audio data arithmetic decoding method and apparatus, and method for truncating audio data bitstream

The scalable audio data arithmetic decoding method and apparatus and a scalable audio bit-stream method of cutting is disclosed. The arithmetic decoding method, a method for decoding a scalable arithmetic coded symbol, comprising: arithmetic decoding using (a) the probability of occurrence of symbols and the symbol to be decoded; And to check the rules aembi eoti (ambiguity) indicating whether or not (b) completes decoding of the symbol includes the step of determining whether to continue decoding. According to the present invention, it is effective to the decoding at the time when applying the scalability (scalablility) according to MPEG-4 arithmetic encoding (arithmetic coding) applied at the sleeve's audio coding (Scalable lossless audio coding) as scalable. And allowing the bit stream is decoded to find out the end, even if the cut (truncation), it is possible to cut off between the additional decoding even for parts.