Source coding enhancement using spectral-band replication

摘要

The present invention proposes a new method and apparatus for the enhancement of source coding systems. The invention employs bandwidth reduction ( 101 ) prior to or in the encoder ( 103 ), followed by spectral-band replication ( 105 ) at the decoder ( 107 ). This is accomplished by the use of new transposition methods, in combination with spectral envelope adjustments. Reduced bitrate at a given perceptual quality or an improved perceptual quality at a given bitrate is offered. The invention is preferably integrated in a hardware or software codec, but can also be implemented as a separate processor in combination with a codec. The invention offers substantial improvements practically independent of codec type and technological progress.