Designing a unified speech/audio codec by adopting a single channel harmonic source separation module

This paper proposes a unified speech/audio codec by adopting a single channel harmonic separation module as a pre-processor. A modulation frequency analysis method is used for harmonic separation, and the separated components are first encoded by an appropriate codec, e.g. speech codec. The error between input and the encoded signal is re- encoded by another codec. Though any type of codec can be used for the purpose, we adopt two state-of-the-art international standards (AMR-WB and HE-AAC) to provide an interoperability option. The amount of allocated bits to each stage is controlled by a power ratio of separated harmonic components to input signal. Subjective listening tests verify the consistency of the proposed method in speech, music and mixed signal inputs.