LOW BITRATE AUDIO ENCODING/DECODING SCHEME HAVING CASCADED SWITCHES

摘要

AN AUDIO ENCODER (421) COMPRISES A FIRST INFORMATION SINK ORIENTED ENCODING BRANCH SUCH AS A SPECTRAL DOMAIN ENCODING BRANCH, A SECOND INFORMATION SOURCE OR SNR ORIENTED ENCODING BRANCH SUCH AS AN LPC-DOMAIN ENCODING BRANCH, AND A SWITCH (200) FOR SWITCHING BETWEEN THE FIRST ENCODING BRANCH (400) AND THE SECOND ENCODING BRANCH (500), WHEREIN THE SECOND ENCODING BRANCH (500) COMPRISES A CONVERTER INTO A SPECIFIC DOMAIN DIFFERENT FROM THE SPECTRAL DOMAIN SUCH AS AN LPC ANALYSIS STAGE (510) GENERATING AN EXCITATION SIGNAL, AND WHEREIN THE SECOND ENCODING BRANCH (500) FUR­ THERMORE COMPRISES A SPECIFIC DOMAIN CODING BRANCH SUCH AS LPC DOMAIN P OCESSING BRANCH, AND A SPECIFIC SPECTRAL DO­ MAIN CODING BRANCH SUCH AS LPC SPECTRAL DOMAIN PROCESSING BRANCH, AND AN ADDITIONAL SWITCH (521) FOR SWITCHING BE­TWEEN THE SPECIFIC DOMAIN CODING BRANCH AND THE SPECIFIC SPECTRAL DOMAIN CODING BRANCH. AN AUDIO DECODER (431) COM­ PRISES A FIRST DOMAIN DECODER SUCH AS A SPECTRAL DOMAIN DE­ CODING BRANCH, A SECOND DOMAIN DECODER SUCH AS AN LPC DOMAIN DECODING BRANCH FOR DECODING A SIGNAL SUCH AS AN EXCI­TATION SIGNAL IN THE SECOND DOMAIN, AND A THIRD DOMAIN DE­ CODER SUCH AS AN LPC-SPECTRAL DECODER BRANCH AND TWO CAS­ CADED SWITCHES FOR SWITCHING BETWEEN THE DECODERS.