Interpolative coding of speech parameters using hierarchical temporal decomposition

A new method for temporal decomposition (TD) of speech parameters for very low rate coding applications is developed. Unlike typical TD, the phonetic relevance is not considered here, instead, we represent the spectral parameters of speech using pre-defined interpolation functions. These functions are located at instants, which give maximum correlation with the true event structure. In this method, no event refinement is required, which significantly reduces the computational complexity of the coder to make real-time implementation possible. The method is also highly flexible and can comply with diverse coding system attributes such as bit-rate, accuracy, delay, and complexity. A spectral distortion of about 1.5 dB is achieved using the method proposed for encoding the LAR parameters at less than 1 kb/s.