MY122805A - Sound quality of establised low bit-rate audio coding systems without loss of decoder compatibility - Google Patents

Abstract

A MULTI-CHANNEL AUDIO COMPRESSION TECHNOLOGY IS PRESENTED THAT EXTENDS THE RANGE OF SAMPLING FREQUENCIES COMPARED TO EXISTING TECHNOLOGIES AND/ OR LOWERS THE NOISE FLOOR WHILE REMAINING COMPATIBLE WITH THOSE EARLIER GENERATION TECHNOLOGIES. THE HIGH-SAMPLING FREQUENCY MULTI-CHANNEL AUDIO IS DECOMPOSED INTO CORE AUDIO UP TO THE EXISTING SAMPLING FREQUENCIES AND A DIFFERENCE SIGNAL (34) UP TO THE SAMPLING FREQUENCIES OF THE NEXT GENERATION TECHNOLOGIES. THE CORE AUDIO IS ENCODED USING A FIRST GENERATION TECHNOLOGY SUCH AS DTS, DOLBY AC-3 OR MPEG I OR II SUCH THAT THE ENCODED CORE BIT STREAM (20) IS FULLY COMPATIBLE WITH A COMPARABLE DECODER IN THE MARKET. THE DIFFERENCE SIGNAL (34) IS ENCODED USING TECHNOLOGIES THAT EXTEND THE SAMPLING FREQUENCY AND/OR IMPROVE THE QUALITY OF THE CORE AUDIO. THE COMPRESSED DIFFERENCE SIGNAL (34) IS ATTACHED AS AN EXTENSION TO THE CORE BIT STREAM (20). THE EXTENSION DATA WILL BE IGNORED BY THE FIRST GENERATION DECODERS BUT CAN BE DECODED BY THE SECOND GENERATION DECODERS. BY SUMMING THE DECODED CORE AND EXTENSION AUDIO SIGNALS TOGETHER A SECOND GENERATION DECODER CAN EFFECTIVELY EXTEND THE AUDIO SIGNAL BANDWIDTH AND/ OR IMPROVE THE SIGNAL TO NOISE RATIO BEYOND THAT AVAILABLE THROUGH THE CORE DECODER (24, 114) ALONE. FIG. 2