Subject: "Phase-Preserving Narrowed Autocorrelation"? From: Fabien Gouyon <fgouyon(at)IUA.UPF.ES> Date: Tue, 19 Nov 2002 19:18:57 +0100List, In "Computational auditory pathways to music understanding" (1997), Barry Vercoe proposes the use of the Phase-Preserving Narrowed Autocorrelation (PPNAC) for detecting recurring patterns and estimating tempo in a representation of the loudness of audio data (1 value each 10 ms it seems). However there's no indication on what that is exactly, how it is computed and where the "phase-preserving" feature resides in. Another feature of the PPNAC seems to be to let large time scale phenomena influence smaller time scales (e.g. a quarter-note pulse would induce a weaker response at eighth-note, triplet-eighths, sixteenths, etc.). I didn't find details on that either. Would somebody have an idea of where to look for more detailed information? Or maybe a hint to understand? Would there be some CSound code around? Thanks ____________________________________________ Fabien Gouyon Music Technology Group IUA-UPF Barcelona http://www.iua.upf.es/~fgouyon tel : (00 34) 93 542 28 64 ____________________________________________