Beat Tapper / DiMaß
DiMaß1, pronounced dee-MAHS2, is a technique for Direct Manipulation Audio Scrubbing and Skimming. It allows you to quickly search, skim, scrub and slide through audio with continuous audio feedback using a constant pitch time-stretching algorithm.
DiMaß is currently implemented as part of Beat Tapper using the Semantic Time Framework. Beat Tapper is a tool for tagging audio files with beat metadata for Mac OS X. It runs on any Mac (Intel or PPC) with OS 10.4.5 (Tiger) or higher. Any QuickTime-compatible movie with audio can be imported into Beat Tapper.
Here is an example beat metadata file for an excerpt of Blue Danube Waltz by Johann Strauss. The corresponding audio file can be obtained from Wikipedia. Wikipedia offers the excerpt in Ogg Vorbis (.ogg) format; you must first convert it to a QuickTime-compatible format before it can be imported into Beat Tapper. I used Audacity to convert the ogg file to a wav file, which can then be imported into Beat Tapper. Alternatively, you can create your own beat file using the Beat Tapper interface.
To use DiMaß, audio time stretching must be enabled: open up the "Audio Controls" panel using from the "View" menu (shortcut: ⌘K). Select either "Stretchy (Phase Vocoder)", or "Pitchy".
2 The "ß" is the German sharp "S", an abbreviation for two S's, not the Greek letter beta.