Design of Progressive Syntax-Rich Multichannel Audio Codec

摘要

Being able to transmit the audio bitstream progressively is a highly desirable property for network transmission. MPEG-4 version-2 audio supports fine grain bit rate scalability in the Generic Audio Coder (GAC). It has a Bit-Sliced Arithmetic Coding (BSAC) tool, which provides scalability in the step of 1 kbit/sec per audio channel. However, this fine grain scalability tool is only available for mono and stereo audio material. Not much work has been done on progressively transmitting multichannel audio sources. MPEG Advanced Audio Coding (AAC) is one of the most distinguished multichannel digital audio compression systems. Based on AAC, we develop a progressive syntax-rich multichannel audio codec in this work. It not only supports fine grain bit rate scalability for the multichannel audio bitstream, but also provides several other desirable functionalities. A formal subjective listening test shows that the proposed algorithm achieves a better performance at several different bit rates when compared with MPEG-4 BSAC for the mono audio sources.