SpHEAR/sphear_fir_render.m

%%
%% *SpHEAR Project
%% sphear_fir_render: render impulse responses throught the FIR filter A2B matrix
%%
%% usage:
%%   [] = sphear_fir_render(FIR, fmin, fmax, N, Npre)
%%
%% FIR: A2B matrix of FIR filters
%% fmin, fmax: range of frequencies to use
%% N: number of samples to filter
%% Npre: number of samples before the main impulse peak
%% Fs: sampling rate
%% plt: plot response
%%
%% Copyright 2016, Fernando Lopez-Lezcano, All Rights Reserved
%% nando@ccrma.stanford.edu
%%
%%  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 3 of the License, or
%%  (at your option) any later version.
%%
%%  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

function [BFF] = sphear_fir_render(FIR, fmin, fmax, N, Npre, Fs, plt)

  [ref, Fs] = wavread('../cal/2016.04.20/export/reference-001-1.wav');
  %% find highest peak location and define sample range
  [index, value] = findmaxpeak(ref);
  r_start = index - Npre;
  r_end = r_start + N -1;
  range = r_start:r_end;
  ref_fft = fft(ref(range), N);
  printf("reference: peak %f at %d, sample range [%d %d]\n", value, index, r_start, r_end);
  
  capnames = cellstr(['LF'; 'RF'; 'LB'; 'RB']);

  raw = 0;
  writefile = 1;

  minindex = N;
  maxpeak = 0;
  
  for m = 1:16
    c1r = wavread(["../cal/2016.04.20/export/a-format-0" sprintf("%02.0f", m) "-" char(capnames(1)) ".wav"]);
    c1 = c1r(range);
    [index, peak] = findmaxpeak(c1r);
    maxpeak = max(maxpeak, abs(peak));
    minindex = min(minindex, (index - r_start));
    w1 = fftfilt(reshape(FIR(1,1,:), 1, [])', c1);
    x1 = fftfilt(reshape(FIR(2,1,:), 1, [])', c1);
    y1 = fftfilt(reshape(FIR(3,1,:), 1, [])', c1);
    z1 = fftfilt(reshape(FIR(4,1,:), 1, [])', c1);

    c2r = wavread(["../cal/2016.04.20/export/a-format-0" sprintf("%02.0f", m) "-" char(capnames(2)) ".wav"]);
    c2 = c2r(range);
    [index, peak] = findmaxpeak(c2r);
    maxpeak = max(maxpeak, peak);
    minindex = min(minindex, (index - r_start));
    w2 = fftfilt(reshape(FIR(1,2,:), 1, [])', c2);
    x2 = fftfilt(reshape(FIR(2,2,:), 1, [])', c2);
    y2 = fftfilt(reshape(FIR(3,2,:), 1, [])', c2);
    z2 = fftfilt(reshape(FIR(4,2,:), 1, [])', c2);

    c3r = wavread(["../cal/2016.04.20/export/a-format-0" sprintf("%02.0f", m) "-" char(capnames(3)) ".wav"]);
    c3 = c3r(range);
    [index, peak] = findmaxpeak(c3r);
    maxpeak = max(maxpeak, peak);
    minindex = min(minindex, (index - r_start));
    w3 = fftfilt(reshape(FIR(1,3,:), 1, [])', c3);
    x3 = fftfilt(reshape(FIR(2,3,:), 1, [])', c3);
    y3 = fftfilt(reshape(FIR(3,3,:), 1, [])', c3);
    z3 = fftfilt(reshape(FIR(4,3,:), 1, [])', c3);

    c4r = wavread(["../cal/2016.04.20/export/a-format-0" sprintf("%02.0f", m) "-" char(capnames(4)) ".wav"]);
    c4 = c4r(range);
    [index, peak] = findmaxpeak(c4r);
    maxpeak = max(maxpeak, peak);
    minindex = min(minindex, (index - r_start));
    w4 = fftfilt(reshape(FIR(1,4,:), 1, [])', c4);
    x4 = fftfilt(reshape(FIR(2,4,:), 1, [])', c4);
    y4 = fftfilt(reshape(FIR(3,4,:), 1, [])', c4);
    z4 = fftfilt(reshape(FIR(4,4,:), 1, [])', c4);

    if (raw == 1)
      wc = (c1 + c2 + c3 + c4);
      xc = (c1 + c2 - c3 - c4);
      yc = (c1 - c2 + c3 - c4);
      zc = (c1 - c2 - c3 + c4);
      rawlabel = "_raw";
    else
      wc = (w1 + w2 + w3 + w4);
      xc = (x1 + x2 + x3 + x4);
      yc = (y1 + y2 + y3 + y4);
      zc = (z1 + z2 + z3 + z4);
      rawlabel = "";
    end

    BFF(:,1,m) = wc;
    BFF(:,2,m) = xc;
    BFF(:,3,m) = yc;
    BFF(:,4,m) = zc;
    
    if (writefile == 1)
      maxw = max(abs(wc));
      maxx = max(abs(xc));
      maxy = max(abs(yc));
      maxz = max(abs(zc));
      maxbf = max([maxw, maxx, maxy, maxz]);
      printf("m%d: max value is %f\n", m, maxbf);
      %% don't know why the written soundfile is clipped...
      %% the max value we calculate is less that 1.0...
      %% so set up an attenuation factor...
      att = 0.05;
      wavwrite(wc * att, Fs, 32, ["../cal/2016.04.20/export/b-format-w-" sprintf("%02.0f", m) ".wav"]);
      wavwrite(xc * att, Fs, 32, ["../cal/2016.04.20/export/b-format-x-" sprintf("%02.0f", m) ".wav"]);
      wavwrite(yc * att, Fs, 32, ["../cal/2016.04.20/export/b-format-y-" sprintf("%02.0f", m) ".wav"]);
      wavwrite(zc * att, Fs, 32, ["../cal/2016.04.20/export/b-format-z-" sprintf("%02.0f", m) ".wav"]);
    end

    if (plt == 1)
      f = figure;
      hold on;
      Nfft = 4096;
      wfft = 20*log10(abs(fft(wc, Nfft)));
      xfft = 20*log10(abs(fft(xc, Nfft)));
      yfft = 20*log10(abs(fft(yc, Nfft)));
      zfft = 20*log10(abs(fft(zc, Nfft)));
      smooth = 12;
      wcr = fastsmooth(wfft, smooth, 2, 1);
      xcr = fastsmooth(xfft, smooth, 2, 1);
      ycr = fastsmooth(yfft, smooth, 2, 1);
      zcr = fastsmooth(zfft, smooth, 2, 1);
      fr = (1:Nfft/2) * Fs/Nfft;
      grid on;
      angle = 360 / 16 * (m - 1); 
      title(sprintf("azimuth = %05.1f degrees", angle));
      axis([300, 20000, -60, 6]);
      tics('y', [6, 0, -2.5, -5, -7.5, -10, -12.5, -15, -17.5, -20, -22.5, -25, -30, -40, -50]);
      semilogx(fr, wcr(1:end/2), 'k;W;');
      semilogx(fr, xcr(1:end/2), 'r;X;');
      semilogx(fr, ycr(1:end/2), 'b;Y;');
      semilogx(fr, zcr(1:end/2), 'g;Z;');
      l = legend('W', 'X', 'Y', 'Z');
      legend(l, 'location', 'southwest');
      hold off;
      print(f, '-dpng','-color',["figures/sphear_b_vs_angle_" sprintf("%03.0f", angle) rawlabel ".png"]);
    end
  end

  [minindex, maxpeak]
end


function [i, v] = findmaxpeak(signal);
  [peaks, locs] = findpeaks(signal, "DoubleSided");
  [~, index] = max(peaks);
  i = locs(index);
  v = peaks(index);
end