A very low latency pitch tracker for audio to MIDI conversion
Authors: Derrien O.
Publication Date: September 2014
Journal: Proc. of the 17th Int. Conference on Digital Audio Effects (DAFx-14), Erlangen, Germany, September 1-5, 2014 (O. Derrien, A very low latency pitch tracker for audio to MIDI conversion, Proc. of the 17th Int. Conference on Digital Audio Effects (DAFx-14), Erlangen, Germany, September 1-5, 2014)
An algorithm for estimating the fundamental frequency of a single- pitch audio signal is described, for application to audio-to-MIDI conversion. In order to minimize latency, this method is based on the ESPRIT algorithm, together with a statistical model for partials frequencies. It is tested on real guitar recordings and compared to the YIN estimator. We show that, in this particular context, both methods exhibit a similar accuracy but the periodicity measure, used for note segmentation, is much more stable with the ESPRIT- based algorithm. This allows to significantly reduce ghost notes. This method is also able to get very close to the theoretical mini- mum latency, i.e. the fundamental period of the lowest observable pitch. Furthermore, it appears that fast implementations can reach a reasonable complexity and could be compatible with real-time, although this is not tested is this study.