function midi = freq2midi(freq)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Name: freq2midi
% Date: March 2018
% Programmer: Christian Dittmar
%
% Converts a given frequency in Hz to the corresponding MIDI pitch, thereby
% applying a quantization to semi-tone steps on the equal tempered scale.
% No sanity checks on the validity of the input are performed.
%
% Input:  freq               the given frequency in Hz
%
% Output: midi               the MIDI pitch, quantized to equal temp. scale
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% If you use the 'NMF toolbox' please refer to:
% [1] Patricio López-Serrano, Christian Dittmar, Yiğitcan Özer, and Meinard
%     Müller
%     NMF Toolbox: Music Processing Applications of Nonnegative Matrix
%     Factorization
%     In Proceedings of the International Conference on Digital Audio Effects
%     (DAFx), 2019.
%
% License:
% This file is part of 'NMF toolbox'.
% https://www.audiolabs-erlangen.de/resources/MIR/NMFtoolbox/
% 'NMF toolbox' is free software: you can redistribute it and/or modify it
% under the terms of the GNU General Public License as published by the
% the Free Software Foundation, either version 3 of the License, or (at
% your option) any later version.
%
% 'NMF toolbox' is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
% Public License for more details.
%
% You should have received a copy of the GNU General Public License along
% with 'NMF toolbox'. If not, see http://www.gnu.org/licenses/.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

midi = round(69 + 12 *log2(freq/440));