matthiasm@0: function [f_audio_out,timepositions_afterDegr] = degradationUnit_applyHarmonicDistortion(f_audio, samplingFreq, timepositions_beforeDegr, parameter)
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: % Name: degradation_applyHarmonicDistortion
matthiasm@0: % Version: 1
matthiasm@0: % Date: 2013-01-25
matthiasm@0: % Programmer: Matthias Mauch
matthiasm@0: %
matthiasm@0: % Description:
matthiasm@0: % - applies quadratic distortion to the audio
matthiasm@0: % - f_audio_out is the distorted audio
matthiasm@0: %
matthiasm@0: % Input:
matthiasm@0: %   f_audio      - audio signal \in [-1,1]^{NxC} with C being the number of
matthiasm@0: %                  channels
matthiasm@0: %   timepositions_beforeDegr - some degradations delay the input signal. If
matthiasm@0: %                             some points in time are given via this
matthiasm@0: %                             parameter, timepositions_afterDegr will
matthiasm@0: %                             return the corresponding positions in the
matthiasm@0: %                             output. Set to [] if unavailable. Set f_audio
matthiasm@0: %                             and samplingFreq to [] to compute only
matthiasm@0: %                             timepositions_afterDegr.
matthiasm@0: %
matthiasm@0: % Input (optional): parameter
matthiasm@0: %   .nApplications = 3  - number of iterative applications. The higher the
matthiasm@0: %                         stronger
matthiasm@0: %   .normalizeOutputAudio = 1 - normalize audio
matthiasm@0: %
matthiasm@0: % Output:
matthiasm@0: %   f_audio_out   - audio signal \in [-1,1]^{NxC} with C being the number
matthiasm@0: %                   of channels
matthiasm@0: %
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: 
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: % Audio Degradation Toolbox
matthiasm@0: %
matthiasm@0: % Centre for Digital Music, Queen Mary University of London.
matthiasm@0: % This file copyright 2013 Sebastian Ewert, Matthias Mauch and QMUL.
matthiasm@0: %    
matthiasm@0: % This program is free software; you can redistribute it and/or
matthiasm@0: % modify it under the terms of the GNU General Public License as
matthiasm@0: % published by the Free Software Foundation; either version 2 of the
matthiasm@0: % License, or (at your option) any later version.  See the file
matthiasm@0: % COPYING included with this distribution for more information.
matthiasm@0: %
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: 
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: % Check parameters
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: if nargin<4
matthiasm@0:     parameter=[];
matthiasm@0: end
matthiasm@0: if nargin<3
matthiasm@0:     timepositions_beforeDegr=[];
matthiasm@0: end
matthiasm@0: if nargin<2
matthiasm@0:     error('Please specify input data');
matthiasm@0: end
matthiasm@0: 
matthiasm@0: if isfield(parameter,'nApplications')==0
matthiasm@0:     parameter.nApplications = 3;
matthiasm@0: end
matthiasm@0: if isfield(parameter,'normalizeOutputAudio')==0
matthiasm@0:     parameter.normalizeOutputAudio = 1;
matthiasm@0: end
matthiasm@0: 
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: % Main program
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: 
matthiasm@0: f_audio_out = [];
matthiasm@0: if ~isempty(f_audio)
matthiasm@0:     f_audio_out = f_audio;
matthiasm@0:     for ii = 1:parameter.nApplications
matthiasm@0:         f_audio_out = sin(f_audio_out * pi/2);
matthiasm@0:     end
matthiasm@0:     
matthiasm@0:     if parameter.normalizeOutputAudio
matthiasm@0:         f_audio_out = adthelper_normalizeAudio(f_audio_out, samplingFreq);
matthiasm@0:     end
matthiasm@0:     
matthiasm@0: end
matthiasm@0: 
matthiasm@0: % This degradation does not impose a delay
matthiasm@0: timepositions_afterDegr = timepositions_beforeDegr;
matthiasm@0: 
matthiasm@0: end