Reduced RateUltraLow Delay Audio Coder using
Multistage VectorQuantization, T.V. Sreenivas · 2007
Communication applications areusually delayre- stricted, especially fortheinstance ofmusicians playing overthe internet. Thisrequires aone-way delay ofmaximum25msecand alsoahighaudio quality isdesired atfeasible bitrates. TheUltra LowDelay(ULD)audiocoding structure iswellsuited tothis application andweinvestigate further theapplication ofmulti- stage vector quantization (MSVQ)toreachabitraterangebelow 64Kb/s, inascalable manner. Results at32Kb/sand64Kb/s showthatthetrained codebook MSVQ performs best, better than KLT normalization followed byasimulated Gaussian MSVQ or simulated Gaussian MSVQ alone. Theresults alsoshowthat there isonlyaweakdependence onthetraining data, andthat we indeed converge totheperceptual quality ofourprevious ULD coderat64Kb/s.