Patent ID: 7333929
Filing Date: 2008-02-19
Classification: G10L

Abstract:
1. A method of encoding a data stream to produce a compressed bitstream having a bit rate lower than or equal to the maximum bit rate of a channel, comprising: separating the data stream into a plurality of frequency components by performing at least one frequency transformation on at least one block of time domain data samples from said data stream; extracting a plurality of tones from said frequency components, said tones comprising signal frequency components approximating a defined base function; ranking extracted tones in order of psychoacoustic importance; selecting a subset of extracted tones for tone encoding, based on said ranking in order of psychoacoustic importance; reconstructing a time domain data stream representing said data stream with said subset of extracted tones removed; bandpass subband filtering said reconstructed time domain signal to separate said reconstructed time domain signal into a plurality of time domain subband signals; ranking said time domain subband signals in order of psychoacoustic importance, from most important to least important; encoding the selected subset of extracted tones to produce encoded tone data; encoding a subset of said time domain subband signals to produce encoded subband signal data; and formatting said encoded tone data and encoded subband signal data into a compressed frame of data in the compressed bitstream, wherein said frame having multiplexed header, tone data, and subband signal data corresponding to a common time frame.