| 摘要 |
<p>A method and apparatus for coding and decoding an audio signal wherein the audio signal is divided into a plurality of frequency subbands and while the subband(s) comprising frequency components below a given threshold frequency (e.g., 1200 Hz) are coded so as to preserve phase information thereof (e.g., the entire waveform is coded), those subbands comprising frequency components above the given threshold frequency are coded without their associated carrier phase information -- i.e., only the envelope of the signal is coded. In accordance with one illustrative embodiment of the invention, these envelopes are advantageously smoothed prior to coding with use, for example, of a 250 Hz low-pass filter. Also in accordance with the illustrative embodiment, the coded subbands are advantageously interleaved and coded in a multi-descriptive manner to produce two independent coded bit streams, one representing, for example, "even" subbands and the other representing, for example, "odd" subbands. Upon reconstruction by the decoder, these two independent bit streams may be advantageously used to generate a stereophonic reconstructed signal comprising a "left" channel and a "right" channel, respectively. <IMAGE></p> |
