Digital Audio Resampling

Aaron Levin will present J. O. Smith's "Digital Audio Resampling Home Page," (https://ccrma.stanford.edu/~jos/resample/resample.pdf) itself an expanded version of J. O. Smith and P. Gossett's “A flexible sampling-rate conversion method" (Proc. 1984 Int. Conf. Acoustics, Speech, and Signal Processing) and its associated implementation in libresample (https://github.com/minorninth/libresample) as used in Audacity and other audio software.

This paper introduces the concept of "resampling" audio signals and an algorithm to perform it. Sound, as it comes out of your speakers, has a peculiar digital representation. It's a sequence of values between -1 and 1. The number of values in your sequence is determined by the "sample rate". A higher sample rate means more values and a higher quality representation. It's helpful sometimes to convert between sampling rates, thus requiring the concept of "resampling."

In this talk we'll introduce the digital representation of audio signals, sample rates, motivate why one might want to re-sample, and finally introduce the algorithm discussed on J. O. Smith's Resample homepage. Like many concepts in computer science, we will take a rather unassuming idea and make it overly complicated by fetishizing performance.

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Please note that we are at RenoRun's new offices. The nearest metro is St-Henri. Go west on Notre-Dame if coming from there. Some nearby buses are 36 and 191.