Scalable lossless audio coding/decoding apparatus and method

A scalable lossless audio decoding apparatus for decoding an audio signal from a bitstream in which a lossy bitstream, in which the audio signal is lossy coded, and a lossless bitstream, in which a lossy audio signal that is lost when the audio signal is lossy coded is lossless coded, are mixed together, the apparatus comprising:

• a demultiplexing unit which demultiplexes the lossy bitstream and the lossless bitstream from the mixed bitstream;
• a lossy decoding unit which decodes the lossy bitstream that is separated from the demultiplexing unit and restores the audio signal;
• a lossless decoding unit which restores the lossless bitstream that is separated from the demultiplexing unit and restores the lossy signal;
• and
• a first signal generator which adds the lossy audio signal that is restored by the lossy decoding unit to the restored lossy signal and restores a lossless audio signal.

A scalable lossless audio coding method comprising:

• (a) lossy coding an input audio signal and generating a lossy bitstream;
• (b) decoding the lossy bitstream, comparing a decoded signal with the input audio signal, and regenerating a lossy signal that is lost when lossy coding is implemented;
• (c) lossless coding the lossy signal and generating the result of lossless coding as a lossless bitstream;
• and
• (d) multiplexing the lossy bitstream with the lossless bitstream and generating one output bitstream.

A scalable lossless audio decoding method for decoding an audio signal from a bitstream in which a lossy bitstream, in which the audio signal is lossy coded, and a lossless bitstream, in which a lossy audio signal that is lost when the audio signal is lossy coded is lossless coded, are mixed together, the method comprising:

• (a) demultiplexing the lossy bitstream and the lossless bitstream from the mixed bitstream;
• (b) decoding the lossy bitstream that is separated from the demultiplexing unit and restoring the audio signal;
• (c) restoring the lossless bitstream that is separated from the demultiplexing unit and restoring the lossy signal;
• and
• (d) adding the lossy audio signal that is restored by the lossy decoding unit to the restored lossy signal and restoring a lossless audio signal.