ivan@138: function [xClipped, IClipped, xClean, clipSizes] = makeClippedSignal(x,clippingLevel,GR)
ivan@138: % Normalize and clip a signal.
ivan@138: %
ivan@138: % Usage:
ivan@138: %   [xClipped, IClipped, xClean, clipSizes] = makeClippedSignal(x,clippingLevel,GR)
ivan@138: %
ivan@138: % Inputs:
ivan@138: %   - x: input signal (may be multichannel)
ivan@138: %   - clippingLevel: clipping level, between 0 and 1
ivan@138: %   - GR (default: false): flag to generate an optional graphical display
ivan@138: %
ivan@138: % Outputs:
ivan@138: %   - xClipped: clipped signal
ivan@138: %   - IClipped: boolean vector (same size as xClipped) that indexes clipped
ivan@138: %   samples
ivan@138: %   - xClean: clean signal
ivan@138: %   - clipSizes: size of the clipped segments
ivan@138: %
ivan@138: % Note that the input signal is normalized to 0.9999 (-1 is not allowed in
ivan@138: % wav files) to provide xClipped and xClean.
ivan@138: %
ivan@138: % -------------------
ivan@138: %
ivan@138: % Audio Inpainting toolbox
ivan@138: % Date: June 28, 2011
ivan@138: % By Valentin Emiya, Amir Adler, Maria Jafari
ivan@138: % This code is distributed under the terms of the GNU Public License version 3 (http://www.gnu.org/licenses/gpl.txt).
ivan@138: 
ivan@138: if nargin<3 || isempty(GR)
ivan@138:     GR = false;
ivan@138: end
ivan@138: 
ivan@138: %% Normalization
ivan@138: xMax = 0.9999;
ivan@138: xClean = x/max(abs(x(:)))*xMax;
ivan@138: clippingLevel = clippingLevel*xMax;
ivan@138: 
ivan@138: %% DISABLED - Ramp to produce a clipping level that linearly increases
ivan@138: if 0
ivan@138:     xClean = xClean.*(1:length(xClean))'/length(xClean);
ivan@138: end
ivan@138: 
ivan@138: %% Clipping (hard threshold)
ivan@138: xClipped = min(max(xClean,-clippingLevel),clippingLevel);
ivan@138: IClipped = abs(xClipped)>=clippingLevel; % related indices
ivan@138: 
ivan@138: %% Size of the clipped segments
ivan@138: if nargout>3 || GR
ivan@138:    %     clipSizes = diff(find(diff(~IClipped)));
ivan@138:    %     clipSizes = clipSizes(2-(IClipped(1)==0):2:end);
ivan@138:    clipSizes = diff(IClipped);
ivan@138:    if clipSizes(find(clipSizes,1,'first'))==-1,clipSizes = [1;clipSizes]; end
ivan@138:    if clipSizes(find(clipSizes,1,'last'))==1,clipSizes = [clipSizes;-1]; end
ivan@138:    clipSizes = diff(find(clipSizes));
ivan@138:    clipSizes = clipSizes(1:2:end);
ivan@138: end
ivan@138: 
ivan@138: %% Optional graphical display
ivan@138: if GR
ivan@138:     
ivan@138:     % Plot histogram of the sizes of the clipped segments
ivan@138:     if ~isempty(clipSizes)
ivan@138:         figure
ivan@138:         hist(clipSizes,1:max(clipSizes))
ivan@138:         title('Size of missing segments')
ivan@138:         xlabel('Size'),ylabel('# of segments')
ivan@138:     end
ivan@138:     
ivan@138:     t = (0:length(xClean)-1); % time scale in samples
ivan@138:     
ivan@138:     % Plot original and clipped signals
ivan@138:     figure
ivan@138:     plot(t,xClean,'',t,xClipped,'')
ivan@138:     legend('original','clipped')
ivan@138:     
ivan@138:     % Scatter plot between original and clipped signals
ivan@138:     figure
ivan@138:     plot(xClean,xClipped,'.')
ivan@138:     xlabel('Original signal'),ylabel('Clipped signal')
ivan@138:     
ivan@138:     % Spectrograms
ivan@138:     N = 512;
ivan@138:     w = hann(N);
ivan@138:     fs = 1;
ivan@138:     NOverlap = round(.8*N);
ivan@138:     nfft = 2^nextpow2(N)*2*2;
ivan@138:     figure
ivan@138:     subplot(3,3,[1,4])
ivan@138:     spectrogram(xClean,w,NOverlap,nfft,fs,'yaxis')
ivan@138:     title('Original')
ivan@138:     xlim(t([1,end]))
ivan@138:     cl = get(gca,'clim');
ivan@138:     set(gca,'clim',cl);
ivan@138:     subplot(3,3,[1,4]+1)
ivan@138:     spectrogram(xClipped,w,NOverlap,nfft,fs,'yaxis')
ivan@138:     title('Clipped')
ivan@138:     set(gca,'clim',cl);
ivan@138:     subplot(3,3,[1,4]+2)
ivan@138:     spectrogram(xClean-xClipped,w,NOverlap,nfft,fs,'yaxis')
ivan@138:     title('Error (=original-clipped)')
ivan@138:     set(gca,'clim',cl);
ivan@138:     subplot(3,3,7)
ivan@138:     plot(t,xClean,'');xlim(t([1,end]))
ivan@138:     subplot(3,3,8)
ivan@138:     plot(t,xClean,'',t,xClipped,'');xlim(t([1,end]))
ivan@138:     subplot(3,3,9)
ivan@138:     plot(t,xClean-xClipped,'');xlim(t([1,end]))
ivan@138: end
ivan@138: 
ivan@138: return