Linear transformation for low bit rate speech coding

This paper discusses the possibility of an input-dependent orthogonal transform for low bit rate speech coding. An orthogonal transform, based on an autoregressive model of short-time input speech, which is applicable to low bit rate coding, is presented. Its performance is evaluated in comparison with that for conventional transforms, KLT and DCT. The experiments confirm that the input-dependent orthogonal transform improves the average distortion versus average information rate performance over that for the input-independent transform DCT.