OBJECT CODING OF HARMONIC SOUNDS USING SPARSE AND STRUCTURE D REPRESENTATIONS
Gregory Cornuz, Emmanuel Ravelli, Pierre Leveau, Laurent Daudet · 2007
Object coding allows audio compression at extremely low bit-rates, provided that the objects are correctly modelled and identified. In this study, a codec has been implemented on the basis of a sparse decomposition of the signal with a dictionary of Instrument-Specific Harmonic atoms. The decomposition algorithm extracts “molecules ” i.e. linear combinations of such atoms, considered as note-like objects. Thus, they can be coded efficiently using notespecific strategies. For signals containing only harmonic sounds, the obtained bitrates are very low, typically around 2 kbs, and informal listening tests against a standard sinusoidal coder show promising performances. 1.