This paper presents a novel buffer management technique that allows time-stretching to be implemented as a live realtime audio effect. Previously, implementing time-stretching as an effect in a realtime audio system with live input and output was not practical due to technical and perceptual problems. This system is based on the circular buffer, but with a non-continuous, audio level triggered write methodology. This modification compensates for the fact that the output of a time-stretcher is longer than the input. This allows synchrony between a live input and output to be maintained as well as reducing the processing and memory requirements. The buffer management technique is paired here with the Paulstretch1 time-stretch algorithm, but can be adapted for use with other time-stretch algorithms as well. Also discussed are the implementation design details including live, manipulatable FFT window size and stretch factor parameters.
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