A switched parametric and transform audio coder

In this paper, we present a system of sines+transients+noise modeling techniques that dynamically switches between parametric representations and transform coding based representations. The sines and noise are represented by parametric models using multiresolution sinusoidal modeling and Bark-band noise modeling, respectively. The transients are modeled by short regions of transform coding. In addition, new methods are presented for selection and quantization of sinusoidal trajectories based on trajectory length and signal-to-masking thresholds. This system is useful for both low bitrate audio coding (20-40 kbps) and compressed-domain processing, such as time-scale modification.