comparison AudioDegradationToolbox/degradationUnits/degradationUnit_adaptiveEqualizer.m @ 28:76f45f5c9afd DoP tip

- added units
  * adaptiveEqualizer
  * applyMfccMeanAdaption
- added corresponding data files for presets
- modified applyImpulseReponse to use the estimated average group delay to adjust
  the output audio and keep the timestamps as is (was vice versa before)
- added new units demos, incl one for applyLowpass

+function [f_audio_out,timepositions_afterDegr] = degradationUnit_adaptiveEqualizer(f_audio, samplingFreq, timepositions_beforeDegr, parameter)
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Name: degradationUnit_adaptiveEqualizer
+% Date of Revision: 2013-01-23
+% Programmer: Sebastian Ewert
+%
+% Description:
+% - designs a filter such that the mean spectrum of f_audio becomes similar
+% to a given mean spectrum
+% - mean spectra are specified using a decibel scale, i.e. if x is a magnitude
+% spectrum, then apply x -> 20*log10(x)
+% - there are four ways to specify the destination mean spectrum: 1. by
+% loading example files provided with the toolbox, 2. by using specific
+% noise "color" profiles, 3. by providing the destination mean spectrum
+% using the parameter destMagFreqResp, 4. by providing audio data from
+% which the destination mean spectrum is computed.
+% - if mean spectra are computed, this is done by computing a magnitude
+% spectrogram, deriving the corresponding values in dB, and then averaging
+% over all time frames.
+% - the same is done for f_audio and the two mean spectral vectors are
+% compared
+% - Then a filter is designed such that f_audio's mean spectral vector
+% becomes similar to destMagFreqResp
+% - filtering is done using a linear-phase FIR filter 
+% - this unit normalizes the output
+%
+% Notes:
+% - note that the mean spectrum is often a good approximation of what is
+% sometimes referred to as the mean spectral shape (however, this term is not
+% defined for general sound recordings). In this sense, the function
+% modifies the mean spectral shape to the desired one.
+%
+% Input:
+%   f_audio      - audio signal \in [-1,1]^{NxC} with C being the number of
+%                  channels
+%   samplingFreq - sampling frequency of f_audio
+%   timepositions_beforeDegr - some degradations delay the input signal. If
+%                             some points in time are given via this
+%                             parameter, timepositions_afterDegr will
+%                             return the corresponding positions in the
+%                             output. Set to [] if unavailable. Set f_audio
+%                             and samplingFreq to [] to compute only
+%                             timepositions_afterDegr.
+%
+% Input (optional): parameter
+%   .loadInternalMagFreqResp=1  - loads one of the destMagFreqResp provided
+%                                 by the toolbox
+%   .internalMagFreqResp='Beatles_NorwegianWood'
+%   .computeMagFreqRespFromAudio - computes destMagFreqResp from given
+%                                  audio data
+%   .computeMagFreqRespFromAudio_audioData
+%                               - audio data for .computeMagFreqRespFromAudio
+%   .computeMagFreqRespFromAudio_sf - sampl freq for .computeMagFreqRespFromAudio
+%   .destMagFreqResp = []       - in db. See above.
+%   .destMagFreqResp_freqs = [] - must have same length as destMagFreqResp.
+%                                 In Hertz
+%   .fftLength = 2 ^ nextpow2(0.02 * samplingFreq); - fft length to
+%                                 calculate spectrogram of f_audio.
+%
+% Output:
+%   f_audio_out   - audio signal \in [-1,1]^{NxC} with C being the number
+%                   of channels
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Audio Degradation Toolbox
+%
+% Centre for Digital Music, Queen Mary University of London.
+% This file copyright 2013 Sebastian Ewert, Matthias Mauch and QMUL.
+%
+% This program is free software; you can redistribute it and/or
+% modify it under the terms of the GNU General Public License as
+% published by the Free Software Foundation; either version 2 of the
+% License, or (at your option) any later version.  See the file
+% COPYING included with this distribution for more information.
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Check parameters
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+if nargin<4
+    parameter=[];
+end
+if nargin<3
+    timepositions_beforeDegr=[];
+end
+if nargin<2
+    error('Please specify input data');
+end
+
+if isfield(parameter,'loadInternalMagFreqResp')==0
+    parameter.loadInternalMagFreqResp = 1;
+end
+if isfield(parameter,'loadNoiseColorPreset')==0
+    parameter.loadNoiseColorPreset = 0;
+end
+if isfield(parameter,'computeMagFreqRespFromAudio')==0
+    parameter.computeMagFreqRespFromAudio = 0;
+end
+
+if isfield(parameter,'internalMagFreqResp')==0
+    parameter.internalMagFreqResp = 'Beethoven_Appasionata_Rwc';
+end
+if isfield(parameter,'noiseColorPreset')==0
+    parameter.noiseColorPreset = 'pink';
+end
+if isfield(parameter,'computeMagFreqRespFromAudio_audioData')==0
+    parameter.computeMagFreqRespFromAudio_audioData = [];
+end
+if isfield(parameter,'computeMagFreqRespFromAudio_sf')==0
+    parameter.computeMagFreqRespFromAudio_sf = [];
+end
+if isfield(parameter,'destMagFreqResp')==0
+    parameter.destMagFreqResp = [];
+end
+if isfield(parameter,'destMagFreqResp_freqs')==0
+    parameter.destMagFreqResp_freqs = [];
+end
+if isfield(parameter,'fftLength')==0
+    parameter.fftLength = 2 ^ nextpow2(0.02 * samplingFreq);
+end
+if isfield(parameter,'filterOrder')==0
+    parameter.filterOrder = round(parameter.fftLength/2);
+end
+if isfield(parameter,'visualizations')==0
+    parameter.visualizations = 0;
+end
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Main program
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+if isempty(f_audio)
+    % we design a linear-phase filter. Such filters have the property that
+    % the group delay for every frequency is always equal to
+    % parameter.filterOrder/2. Therefore, although we built a signal
+    % adaptive filter, we can adjust for that delay. That means that the
+    % timepositions_beforeDegr don't require any adjustment.
+    timepositions_afterDegr = timepositions_beforeDegr;
+    return;
+end
+
+% load/compute destMagFreqResp
+[destMagFreqResp,destMagFreqResp_freqs] = internal_getDestMagFreqResp(parameter);
+
+% compute mean spectral vector for f_audio
+[meanMagSpec,meanMagSpec_freqs] = internal_computeMeanSpectralVector(f_audio,samplingFreq,parameter.fftLength);
+meanMagSpec = internal_standardizeMagFreqResp(meanMagSpec);
+
+% compute magnitude response for the filter to be designed
+destMagFreqResp_org = destMagFreqResp;
+destMagFreqResp_freqs_org = destMagFreqResp_freqs;
+if ~((length(destMagFreqResp_freqs)==length(meanMagSpec_freqs)) && (all(meanMagSpec_freqs(:) == destMagFreqResp_freqs(:))))
+    % in this case we interpolate the frequency response using a
+    % spline interpolation
+    destMagFreqResp = spline(destMagFreqResp,destMagFreqResp_freqs,meanMagSpec_freqs);
+end
+filter_magFreqResp = destMagFreqResp(:) - meanMagSpec(:);
+
+% design filter (fir2 is linear phase)
+filter_magFreqResp_linear = 10 .^ (filter_magFreqResp/20);
+b = fir2(parameter.filterOrder,meanMagSpec_freqs/(samplingFreq/2),filter_magFreqResp_linear);
+
+% apply filter
+parameterApplyImpulseResponse.loadInternalIR = 0;
+parameterApplyImpulseResponse.impulseResponse = b;
+parameterApplyImpulseResponse.impulseResponseSampFreq = samplingFreq;
+parameterApplyImpulseResponse.normalizeOutputAudio = 1;
+parameterApplyImpulseResponse.averageGroupDelayOfFilter = round(parameter.filterOrder/2);
+[f_audio_out,timepositions_afterDegr] = degradationUnit_applyImpulseResponse(f_audio, samplingFreq, timepositions_beforeDegr, parameterApplyImpulseResponse);
+
+if parameter.visualizations
+    fvtool(b,1);
+    
+    [meanMagSpecOut,meanMagSpecOut_freqs] = internal_computeMeanSpectralVector(f_audio_out,samplingFreq,parameter.fftLength);
+    meanMagSpecOut = internal_standardizeMagFreqResp(meanMagSpecOut);
+    
+    figure;
+    plot(destMagFreqResp_freqs_org,destMagFreqResp_org,'y');
+    hold on;
+    plot(meanMagSpecOut_freqs,meanMagSpecOut,'k');
+    title('Comparison: destMagFreqResp(y) and mean spectral vector of output(k)')
+end
+
+
+end
+
+function [f_meanmagspec_db,freqs] = internal_computeMeanSpectralVector(f_audio,fs,fftLength)
+
+f_audio = mean(f_audio,2);
+
+[f_spec,freqs,time] = spectrogram(f_audio,hanning(fftLength),fftLength/2,fftLength,fs);
+
+f_magspec_db = 20 * log10(abs(f_spec));
+
+f_magspec_db(:,isinf(sum(abs(f_magspec_db),1))) = []; % ignore columns with -inf/inf entries
+f_magspec_db(:,isnan(sum(abs(f_magspec_db),1))) = [];
+
+f_meanmagspec_db = mean(f_magspec_db,2);
+
+end
+
+function magFreqResp = internal_standardizeMagFreqResp(magFreqResp)
+
+temp = magFreqResp(~isinf(magFreqResp));
+temp = temp(~isnan(magFreqResp));
+maxRobust = max(temp);
+
+magFreqResp = magFreqResp - maxRobust;
+
+magFreqResp(magFreqResp > 0) = 0;  % remaining positive inf
+magFreqResp(magFreqResp < -80) = -80;  % remaining positive inf
+
+end
+
+function [destMagFreqResp,destMagFreqResp_freqs,fftLength] = internal_getDestMagFreqResp(parameter)
+if parameter.loadInternalMagFreqResp
+    % load example included in toolbox
+    
+    fullFilenameMfile = mfilename('fullpath');
+    [pathstr,name,ext] = fileparts(fullFilenameMfile);
+    dirRootIRs = fullfile(pathstr,'../degradationData');
+    
+    names_internal = {'Beatles_NorwegianWood','Beethoven_Appasionata_Rwc'};
+    indexInternal = find(strcmpi(names_internal,parameter.internalMagFreqResp), 1);
+    if isempty(indexInternal)
+        error('Please specify a valid internal name')
+    end
+    
+    switch indexInternal
+        case 1
+            file = fullfile(dirRootIRs,'SpecEnvelopes/Beatles_NorwegianWood.mat');
+        case 2
+            file = fullfile(dirRootIRs,'SpecEnvelopes/Beethoven_Appasionata_Rwc.mat');
+    end
+    load(file, 'destMagFreqResp', 'destMagFreqResp_freqs');
+    
+elseif parameter.loadNoiseColorPreset
+    switch(lower( parameter.noiseColorPreset))
+        case 'white'
+            freqExponent = 0;
+        case 'pink'
+            freqExponent = 0.5;
+        case 'brown'
+            freqExponent = 1;
+        case 'blue'
+            freqExponent = -0.5;
+        case 'violet'
+            freqExponent = -1;
+    end
+    
+    lengthMagResp = parameter.fftLength/2+1;
+    destMagFreqResp_freqs = linspace(0,samplingFreq/2,lengthMagResp);
+    magResp = 1./destMagFreqResp_freqs.^freqExponent;
+    magResp(1) = 1;
+    destMagFreqResp = 20 * log10(magResp);
+    
+elseif parameter.computeMagFreqRespFromAudio
+    % compute destMagFreqResp as mean spectral vector from given audio data
+    [destMagFreqResp,destMagFreqResp_freqs] = internal_computeMeanSpectralVector(...
+        parameter.computeMagFreqRespFromAudio_audioData,parameter.computeMagFreqRespFromAudio_sf,parameter.fftLength);
+else
+    destMagFreqResp = parameter.destMagFreqResp;
+    destMagFreqResp_freqs = parameter.destMagFreqResp_freqs;
+end
+
+% standardize destMagFreqResp
+destMagFreqResp = internal_standardizeMagFreqResp(destMagFreqResp);
+end
+
+
+
+
+
+