A Scalable Bandwidth Extension Algorithm

Most modern bandwidth extension techniques predict the high- frequency band based on features extracted from the lower band. While this works for some frames, problems arise when the correlation between the low and the high band is insufficient. In these situations, additional high-band information must be sent to the decoder. In this paper, we propose a scalable speech coding method based on the principles of bandwidth extension. The rate selection is based on explicit psychoacoustic criteria, while the bandwidth extension is performed using a constrained MMSE estimation technique. Objective and subjective evaluations indicate that the proposed system performs at a lower average bit rate when compared to other similar algorithms while improving speech quality.