matthiasm@0: function [f_audio_out,timepositions_afterDegr] = applyDegradation(degradationname, f_audio, samplingFreq, timepositions_beforeDegr)
matthiasm@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
matthiasm@0: % Name: applyDegradation
matthiasm@0: % Date of Revision: 2013-04
matthiasm@0: % Programmer: Sebastian Ewert
matthiasm@0: %
matthiasm@0: % Description:
matthiasm@0: % - in the ADT, (high-level) degradations are usually combinations of several
matthiasm@0: %   degradation units, using specific parameters
matthiasm@0: % - the "degradations" directory contains various degradations. They look like this:
matthiasm@0: %   ----------------------------------------------------------------%   
matthiasm@0: %   degradation_config(1).methodname = 'degradationUnit_applyImpulseResponse';
matthiasm@0: %   degradation_config(1).parameter.loadInternalIR = 1;
matthiasm@0: %   degradation_config(1).parameter.internalIR = 'GreatHall1';
matthiasm@0: %
matthiasm@0: %   degradation_config(2).methodname = 'degradationUnit_addNoise';
matthiasm@0: %   degradation_config(2).parameter.snrRatio = 40; % in dB
matthiasm@0: %   ----------------------------------------------------------------%   
matthiasm@0: % - This degradation specifies that f_audio should first be degraded using the
matthiasm@0: %   degradation unit degradationUnit_applyImpulseResponse and subsequently
matthiasm@0: %   using degradationUnit_addNoise. This works like a chain
matthiasm@0: % - To specify which degradation to use simply set degradationname accordingly.
matthiasm@0: % - If you specify timepositions_beforeDegr, then timepositions_afterDegr
matthiasm@0: %   will contain the corresponding time position in the output audio file.
matthiasm@0: %   Set f_audio=[] and samplingFreq=0 if you want to process only time
matthiasm@0: %   positions
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: %   samplingFreq - sampling frequency of f_audio
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: % Output:
matthiasm@0: %   f_audio_out   - audio signal \in [-1,1]^{NxC} with C being the number
matthiasm@0: %                   of channels
matthiasm@0: %   timepositions_afterDegr - time positions corresponding to timepositions_beforeDegr
matthiasm@0: %                             after all degradations are applied
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: if nargin<4
matthiasm@0:     timepositions_beforeDegr=[];
matthiasm@0: end
matthiasm@0: if nargin<3
matthiasm@0:     error('Please specify the required input variables')
matthiasm@0: end
matthiasm@0: 
matthiasm@0: % the degradations are in a subdirectory called "degradations" of the folder this
matthiasm@0: % function is in
matthiasm@0: fullFilenameMfile = mfilename('fullpath');
matthiasm@0: [pathstr,name,ext] = fileparts(fullFilenameMfile);
matthiasm@0: dirDegradations = fullfile(pathstr,'degradations');
matthiasm@0: 
matthiasm@0: % add dirDegradations to matlab path if it is not included yet. Otherwise we
matthiasm@0: % cannot call the degradation functions
matthiasm@0: addpath(dirDegradations);
matthiasm@0: 
matthiasm@0: % retrieve the degradation configuration
matthiasm@0: degradationFunction = str2func(degradationname);
matthiasm@0: degradation_config = degradationFunction();
matthiasm@0: 
matthiasm@0: % traverse degradation_config and call all the degradation units specified in there
matthiasm@0: numDegradationUnits = length(degradation_config);
matthiasm@0: f_audio_out = f_audio;
matthiasm@0: timepositions_afterDegr = timepositions_beforeDegr;
matthiasm@0: for n=1:numDegradationUnits
matthiasm@0:     degradationFunction = str2func(degradation_config(n).methodname);
matthiasm@0:     [f_audio_out,timepositions_afterDegr] = degradationFunction(f_audio_out, samplingFreq, timepositions_afterDegr, degradation_config(n).parameter);
matthiasm@0: end
matthiasm@0: 
matthiasm@0: end
matthiasm@0: 
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