Nonuniform filter banks for audio encoding
Zaiwang Dong · Journal of Tsinghua University(Science and Technology) · 2005
Time-frequency mapping (TFM) of audio coding is improved by generalized FV-ELT (frequency-varying extended lapped transforms) derived based on FV-MLT (frequency-varying modulated lapped transforms). A class of nonuniform filter banks was constructed using FV-ELT with a variable time-frequency resolution. The filters provide more flexible TFM when applied to transient signals, while guaranteeing a higher frequency resolution for stationary signals. Theoretical analysis shows that FV-ELT give a higher transform gain than FV-MLT or MLT. Simulation results for an example with 8 nonuniform subbands shows that FV-ELT are superior to FV-MLT for some frequency properties. Thus, FV-ELT are a class of TFM filter banks for audio encoding with a higher encoding efficiency.