Exploration of Karhunen-Loeve transform for multichannel audio coding
Dai Tracy Yang, Hongmei Ai, Christos Kyriakakis, C.‐C. Jay Kuo · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2000
A new quality-scalable multichannel audio compression algorithm based on MPEG-2 Advanced Audio Coding (AAC) is developed in this work. The Karhunen-Loeve Transform (KLT) is applied to multichannel audio signals in the preprocessing stage to remove the inter-channel redundancy. Then, signals in de-correlated channels are compressed by using a modified AAC main profile encoder. Finally, a channel transmission control mechanism is used to re-organize the bit stream so that the multichannel audio bit stream has a quality scalable property when it is transmitted over a heterogeneous network. Experimental results show that, compared with AAC, the proposed algorithm achieves a better performance with the objective Mask-to-Noise-Ratio (MNR) measurement while maintaining a similar computational complexity at the regular bit rate of 64 kbit/sec/ch. When the bit stream is transmitted to narrowband end users at a lower bit rate, packets of some channels can be dropped and audio of full channel can still be reconstructed in a reasonable fashion.