Tomofumi Yamanashi

Low Bit-Rate High-Quality Audio Encoding and Low Complexity Bandwidth Extension Technologies for ITU-T G.718/G.718-SWB

We worked toward development of a low bit-rate encoding algorithm and a low-complexity encoding algorithm for G.718/G.718-SWB, a new standard of International Telecommunication Union - Telecommunication Standardization Sector (ITU-T). Many key technologies including Band-Selective Shape-Gain Coding (BS-SGC) were developed for the standard. BS-SGC can encode the audio signal efficiently at a low bit-rate. Great improvement was confirmed by official subjective testing. Furthermore, our low-complexity technologies can reduce the computational complexity substantially with no quality degradation of the output signal. They were adopted as featured components of G.718/G.718-SWB, which were approved, respectively, in June 2008 (G.718) and in March 2010 (G.718-SWB).