A Low Power SBR Algorithm for the MPEG-4 Audio Standard and its DSP implementation

摘要

This paper proposes a Low Power Spectral Band Replication algorithm (LP-SBR) adopted in the MPEG-4 Audio standard. It operates with low computational complexity compared to the conventional SBR algorithm called the High Quality SBR algorithm (HQ-SBR). LP-SBR utilizes real-valued processing instead of complex-valued processing used in HQ-SBR for complexity reduction. To minimize the sound quality degradation caused by this reduction, LP-SBR employs aliasing reduction techniques and a gain compensation technique. Subjective quality test results show that there is no statistical difference between LP-SBR and HQ-SBR when they are incorporated into AAC decoders. A complexity comparison of both SBR decoders implemented on 16-bit fixed-point DSPs shows that an AAC decoder with LP-SBR requires 30% less computational complexity than that with HQ-SBR.