A new intensity stereo coding scheme for MPEG1 audio encoder-layers I and II

In the MPEG 1 audio compression standard, the intensity stereo coding scheme is a key technology to achieve a bit rate lower than 2×128 kbit/s for stereophonic signals while preserving the high audio quality. However, the intensity coding scheme has difficulties in the signal cancellation and scale-factor consistency. This paper shows that the Karhunen-Loeve (KL) transform can be applied to the intensity coding for solving the two problems. We present two methods used to implement the Karhunen-Loeve transform in the MPEG 1 layers I and II. Among the two methods, one is fully compatible with the MPEG 1 while the other need a slight modification on the MPEG coding process. The two methods are tested and shown to have a better audio quality than the technique indicated by the MPEG 1 layers I and II