X-Git-Url: https://git.sesse.net/?p=pitch;a=blobdiff_plain;f=pitch.cpp;h=12cf6d8cb8ddfdcb2d092d494255c2e60a67edc5;hp=c8246dcf5f28436277ad51c6cff8bf94f145bc64;hb=fa1b9cdf79b7688a8fec21e3a13eb8d8e6505391;hpb=2bb871a3a6ca4b73e8583de4de97f7b55dd1614c diff --git a/pitch.cpp b/pitch.cpp index c8246dc..12cf6d8 100644 --- a/pitch.cpp +++ b/pitch.cpp @@ -1,4 +1,5 @@ #include +#include #include #include #include @@ -9,6 +10,8 @@ #include #include +#include "pitchdetector.h" + #define SAMPLE_RATE 22050 #define FFT_LENGTH 4096 /* in samples */ #define PAD_FACTOR 2 /* 1/pf of the FFT samples are real samples, the rest are padding */ @@ -23,44 +26,20 @@ #define TUNING WELL_TEMPERED_GUITAR int get_dsp_fd(); -void read_chunk(int fd, double *in, unsigned num_samples); -void apply_window(double *in, double *out, unsigned num_samples); -std::pair find_peak(double *in, unsigned num_samples); -void find_peak_magnitudes(std::complex *in, double *out, unsigned num_samples); -std::pair adjust_for_overtones(std::pair base, double *in, unsigned num_samples); -double bin_to_freq(double bin, unsigned num_samples); -double freq_to_bin(double freq, unsigned num_samples); -std::string freq_to_tonename(double freq); -std::pair interpolate_peak(double ym1, double y0, double y1); +void read_chunk(int fd, short *in, unsigned num_samples); void print_spectrogram(double freq, double amp); void write_sine(int dsp_fd, double freq, unsigned num_samples); int main() { - double *in, *in_windowed; - std::complex *out; - double *bins; - fftw_plan p; - - // allocate memory - in = reinterpret_cast (fftw_malloc(sizeof(double) * FFT_LENGTH / PAD_FACTOR)); - in_windowed = reinterpret_cast (fftw_malloc(sizeof(double) * FFT_LENGTH)); - out = reinterpret_cast *> (fftw_malloc(sizeof(std::complex) * (FFT_LENGTH / 2 + 1))); - bins = reinterpret_cast (fftw_malloc(sizeof(double) * (FFT_LENGTH / 2 + 1))); - - memset(in, 0, sizeof(double) * FFT_LENGTH / PAD_FACTOR); - - // init FFTW - p = fftw_plan_dft_r2c_1d(FFT_LENGTH, in_windowed, reinterpret_cast (out), FFTW_ESTIMATE); + PitchDetector pd(SAMPLE_RATE, FFT_LENGTH, PAD_FACTOR, OVERLAP); int fd = get_dsp_fd(); for ( ;; ) { - read_chunk(fd, in, FFT_LENGTH); - apply_window(in, in_windowed, FFT_LENGTH); - fftw_execute(p); - find_peak_magnitudes(out, bins, FFT_LENGTH); - std::pair peak = find_peak(bins, FFT_LENGTH); - peak = adjust_for_overtones(peak, bins, FFT_LENGTH); + short buf[FFT_LENGTH / PAD_FACTOR / OVERLAP]; + + read_chunk(fd, buf, FFT_LENGTH / PAD_FACTOR / OVERLAP); + std::pair peak = pd.detect_pitch(buf); if (peak.first < 50.0 || peak.second - log10(FFT_LENGTH) < 0.0) { #if TUNING == WELL_TEMPERED_GUITAR @@ -104,36 +83,29 @@ int get_dsp_fd() } #if 1 -void read_chunk(int fd, double *in, unsigned num_samples) +void read_chunk(int fd, short *in, unsigned num_samples) { int ret; - unsigned to_read = num_samples / PAD_FACTOR / OVERLAP; - short buf[to_read]; - memmove(in, in + to_read, (num_samples / PAD_FACTOR - to_read) * sizeof(double)); - - ret = read(fd, buf, to_read * sizeof(short)); + ret = read(fd, in, num_samples * sizeof(short)); if (ret == 0) { printf("EOF\n"); exit(0); } - if (ret != int(to_read * sizeof(short))) { + if (ret != int(num_samples * sizeof(short))) { // blah perror("read"); exit(1); } - - for (unsigned i = 0; i < to_read; ++i) - in[i + (num_samples / PAD_FACTOR - to_read)] = double(buf[i]); } #else // make a pure 440hz sine for testing -void read_chunk(int fd, double *in, unsigned num_samples) +void read_chunk(int fd, short *in, unsigned num_samples) { static double theta = 0.0; for (unsigned i = 0; i < num_samples; ++i) { - in[i] = cos(theta); + in[i] = 32768.0 * cos(theta); theta += 2.0 * M_PI * 440.0 / double(SAMPLE_RATE); } } @@ -152,218 +124,6 @@ void write_sine(int dsp_fd, double freq, unsigned num_samples) write(dsp_fd, buf, num_samples * sizeof(short)); } -// Apply a standard Hamming window to our input data. -void apply_window(double *in, double *out, unsigned num_samples) -{ - static double *win_data; - static unsigned win_len; - static bool win_inited = false; - - // Initialize the window for the first time - if (!win_inited) { - win_len = num_samples / PAD_FACTOR; - win_data = new double[win_len]; - - for (unsigned i = 0; i < win_len; ++i) { - win_data[i] = 0.54 - 0.46 * cos(2.0 * M_PI * double(i) / double(win_len - 1)); - } - - win_inited = true; - } - - assert(win_len == num_samples / PAD_FACTOR); - - for (unsigned i = 0; i < win_len; ++i) { - out[i] = in[i] * win_data[i]; - } - for (unsigned i = win_len; i < num_samples; ++i) { - out[i] = 0.0; - } -} - -void find_peak_magnitudes(std::complex *in, double *out, unsigned num_samples) -{ - for (unsigned i = 0; i < num_samples / 2 + 1; ++i) - out[i] = abs(in[i]); -} - -std::pair find_peak(double *in, unsigned num_samples) -{ - double best_peak = in[0]; - unsigned best_bin = 0; - - for (unsigned i = 1; i < num_samples / 2 + 1; ++i) { - if (in[i] > best_peak) { - best_peak = in[i]; - best_bin = i; - } - } - - if (best_bin == 0 || best_bin == num_samples / 2) { - return std::make_pair(-1.0, 0.0); - } - -#if 0 - printf("undertone strength: %+4.2f %+4.2f %+4.2f [%+4.2f] %+4.2f %+4.2f %+4.2f\n", - 20.0 * log10(in[best_bin*4] / FFT_LENGTH), - 20.0 * log10(in[best_bin*3] / FFT_LENGTH), - 20.0 * log10(in[best_bin*2] / FFT_LENGTH), - 20.0 * log10(in[best_bin] / FFT_LENGTH), - 20.0 * log10(in[best_bin/2] / FFT_LENGTH), - 20.0 * log10(in[best_bin/3] / FFT_LENGTH), - 20.0 * log10(in[best_bin/4] / FFT_LENGTH)); -#endif - - // see if we might have hit an overtone (set a limit of 5dB) - for (unsigned i = 4; i >= 1; --i) { - if (best_bin != best_bin / i && - 20.0 * log10(in[best_bin] / in[best_bin / i]) < 5.0f) { -#if 0 - printf("Overtone of degree %u!\n", i); -#endif - best_bin /= i; - - // consider sliding one bin up or down - if (best_bin > 0 && in[best_bin - 1] > in[best_bin] && in[best_bin - 1] > in[best_bin - 2]) { - --best_bin; - } else if (best_bin < num_samples / 2 && in[best_bin + 1] > in[best_bin] && in[best_bin + 1] > in[best_bin + 2]) { - ++best_bin; - } - - break; - } - } - - if (best_bin == 0 || best_bin == num_samples / 2) { - return std::make_pair(-1.0, 0.0); - } - std::pair peak = - interpolate_peak(in[best_bin - 1], - in[best_bin], - in[best_bin + 1]); - - return std::make_pair(bin_to_freq(double(best_bin) + peak.first, num_samples), peak.second); -} - -// it's perhaps not ideal to _first_ find the peak and _then_ the harmonics -- -// ideally, one should find the set of all peaks and then determine the likely -// base from that... something for later. :-) -std::pair adjust_for_overtones(std::pair base, double *in, unsigned num_samples) -{ - double mu = base.first, var = 1.0 / (base.second * base.second); - - //printf("Base at %.2f (amp=%5.2fdB)\n", base.first, base.second); - - for (unsigned i = 2; i < 10; ++i) { - unsigned middle = unsigned(floor(freq_to_bin(base.first, num_samples) * i + 0.5)); - unsigned lower = middle - (i+1)/2, upper = middle + (i+1)/2; - - if (upper >= num_samples) - upper = num_samples - 2; - - // printf("Searching in [%u,%u] = %f..%f\n", lower, upper, bin_to_freq(lower, num_samples), bin_to_freq(upper, num_samples)); - - // search for a peak in this interval - double best_harmonics_freq = -1.0; - double best_harmonics_amp = -1.0; - for (unsigned j = lower; j <= upper; ++j) { - if (in[j] > in[j-1] && in[j] > in[j+1]) { - std::pair peak = - interpolate_peak(in[j - 1], - in[j], - in[j + 1]); - - if (peak.second > best_harmonics_amp) { - best_harmonics_freq = bin_to_freq(j + peak.first, num_samples); - best_harmonics_amp = peak.second; - } - } - } - - if (best_harmonics_amp <= 0.0) - continue; - - //printf("Found overtone %u at %.2f (amp=%5.2fdB)\n", i, best_harmonics_freq, - // best_harmonics_amp); - - double this_mu = best_harmonics_freq / double(i); - double this_var = 1.0 / (best_harmonics_amp * best_harmonics_amp); - - double k = var / (var + this_var); - mu = (1.0 - k) * mu + k * this_mu; - var *= (1.0 - k); - } - return std::make_pair(mu, base.second); -} - -double bin_to_freq(double bin, unsigned num_samples) -{ - return bin * SAMPLE_RATE / double(num_samples); -} -double freq_to_bin(double freq, unsigned num_samples) -{ - return freq * double(num_samples) / double(SAMPLE_RATE); -} - -/* - * Given three bins, find the interpolated real peak based - * on their magnitudes. To do this, we execute the following - * plan: - * - * Fit a polynomial of the form ax^2 + bx + c = 0 to the data - * we have. Maple readily yields our coefficients, assuming - * that we have the values at x=-1, x=0 and x=1: - * - * > f := x -> a*x^2 + b*x + c; - * - * 2 - * f := x -> a x + b x + c - * - * > cf := solve({ f(-1) = ym1, f(0) = y0, f(1) = y1 }, { a, b, c }); - * - * y1 ym1 y1 ym1 - * cf := {c = y0, b = ---- - ---, a = ---- + --- - y0} - * 2 2 2 2 - * - * Now let's find the maximum point for the polynomial (it has to be - * a maximum, since y0 is the greatest value): - * - * > xmax := solve(subs(cf, diff(f(x), x)) = 0, x); - * - * -y1 + ym1 - * xmax := ------------------- - * 2 (y1 + ym1 - 2 y0) - * - * We could go further and insert {fmax,a,b,c} into the original - * polynomial, but it just gets hairy. We calculate a, b and c separately - * instead. - * - * http://www-ccrma.stanford.edu/~jos/parshl/Peak_Detection_Steps_3.html - * claims that detection is almost twice as good when using dB scale instead - * of linear scale for the input values, so we use that. (As a tiny bonus, - * we get back dB scale from the function.) - */ -std::pair interpolate_peak(double ym1, double y0, double y1) -{ - ym1 = log10(ym1); - y0 = log10(y0); - y1 = log10(y1); - -#if 0 - assert(y0 >= y1); - assert(y0 >= ym1); -#endif - - double a = 0.5 * y1 + 0.5 * ym1 - y0; - double b = 0.5 * y1 - 0.5 * ym1; - double c = y0; - - double xmax = (ym1 - y1) / (2.0 * (y1 + ym1 - 2.0 * y0)); - double ymax = 20.0 * (a * xmax * xmax + b * xmax + c) - 90.0; - - return std::make_pair(xmax, ymax); -} - std::string freq_to_tonename(double freq) { std::string notenames[] = { "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" }; @@ -443,6 +203,7 @@ void print_spectrogram(double freq, double amp) printf(" (%s %+.2f, %5.2fHz) [%5.2fdB] [", notes[best_away_ind].notename, best_away, freq, amp); + // coarse tuning for (int i = -10; i <= 10; ++i) { if (best_away >= (i-0.5) * 0.05 && best_away < (i+0.5) * 0.05) { printf("#"); @@ -454,6 +215,20 @@ void print_spectrogram(double freq, double amp) } } } + printf("] ["); + + // fine tuning + for (int i = -10; i <= 10; ++i) { + if (best_away >= (i-0.5) * 0.01 && best_away < (i+0.5) * 0.01) { + printf("#"); + } else { + if (i == 0) { + printf("|"); + } else { + printf("-"); + } + } + } printf("]\n"); } #endif