diff options
Diffstat (limited to 'tuner.c')
| -rw-r--r-- | tuner.c | 163 |
1 files changed, 138 insertions, 25 deletions
@@ -25,6 +25,115 @@ static double peak_freq = -1.0; static int capturing = 1; +struct note { + const char *name; + double freq; +}; + +/* Frequencies taken from Wikipedia + * https://de.wikipedia.org/wiki/Frequenzen_der_gleichstufigen_Stimmung + */ +struct note note_table[] = { + { "---", 00.0000 }, + { "C0 ", 16.3516 }, + { "C#0", 17.3239 }, + { "D0 ", 18.3540 }, + { "D#0", 19.4454 }, + { "E0 ", 20.6017 }, + { "F0 ", 21.8268 }, + { "F#0", 23.1247 }, + { "G0 ", 24.4997 }, + { "G#0", 25.9565 }, + { "A0 ", 27.5000 }, + { "A#0", 29.1352 }, + { "B0 ", 30.8677 }, + { "C1 ", 32.7032 }, + { "C#1", 34.6478 }, + { "D1 ", 36.7081 }, + { "D#1", 38.8909 }, + { "E1 ", 41.2034 }, + { "F1 ", 43.6535 }, + { "F#1", 46.2493 }, + { "G1 ", 48.9994 }, + { "G#1", 51.9131 }, + { "A1 ", 55.0000 }, + { "A#1", 58.2705 }, + { "B1 ", 61.7354 }, + { "C2 ", 65.4064 }, + { "C#2", 69.2957 }, + { "D2 ", 73.4162 }, + { "D#2", 77.7817 }, + { "E2 ", 82.4069 }, + { "F2 ", 87.3071 }, + { "F#2", 92.4986 }, + { "G2 ", 97.9989 }, + { "G#2", 103.826 }, + { "A2 ", 110.000 }, + { "A#2", 116.541 }, + { "B2 ", 123.471 }, + { "C3 ", 130.813 }, + { "C#3", 138.591 }, + { "D3 ", 146.832 }, + { "D#3", 155.563 }, + { "E3 ", 164.814 }, + { "F3 ", 174.614 }, + { "F#3", 184.997 }, + { "G3 ", 195.998 }, + { "G#3", 207.652 }, + { "A3 ", 220.000 }, + { "A#3", 233.082 }, + { "B3 ", 246.942 }, + { "C4 ", 261.626 }, + { "C#4", 277.183 }, + { "D4 ", 293.665 }, + { "D#4", 311.127 }, + { "E4 ", 329.628 }, + { "F4 ", 349.228 }, + { "F#4", 369.994 }, + { "G4 ", 391.995 }, + { "G#4", 415.305 }, + { "A4 ", 440.000 }, + { "A#4", 466.164 }, + { "B4 ", 493.883 }, + { "C5 ", 523.251 }, + { "C#5", 554.365 }, + { "D5 ", 587.330 }, + { "D#5", 622.254 }, + { "E5 ", 659.255 }, + { "F5 ", 698.456 }, + { "F#5", 739.989 }, + { "G5 ", 783.991 }, + { "G#5", 830.609 }, + { "A5 ", 880.000 }, + { "A#5", 932.328 }, + { "B5 ", 987.767 }, + { "C6 ", 1046.50 }, + { "C#6", 1108.73 }, + { "D6 ", 1174.66 }, + { "D#6", 1244.51 }, + { "E6 ", 1318.51 }, + { "F6 ", 1396.91 }, + { "F#6", 1479.98 }, + { "G6 ", 1567.98 }, + { "G#6", 1661.22 }, + { "A6 ", 1760.00 }, + { "A#6", 1864.66 }, + { "B6 ", 1975.53 }, + { "C7 ", 2093.00 }, + { "C#7", 2217.46 }, + { "D7 ", 2349.32 }, + { "D#7", 2489.02 }, + { "E7 ", 2637.02 }, + { "F7 ", 2793.83 }, + { "F#7", 2959.96 }, + { "G7 ", 3135.96 }, + { "G#7", 3322.44 }, + { "A7 ", 3520.00 }, + { "A#7", 3729.31 }, + { "B7 ", 3951.07 }, + { "C8 ", 4186.01 }, +}; + static void handle_signals(int signum __attribute__((unused))) { capturing = 0; @@ -88,14 +197,14 @@ static void fft_cleanup() fftw_free(fft_out); } -static void update_output(double freq, char note, int dir) +static void update_output(double freq, const char *note, int dir) { - char note_str[] = "---"; + char note_str[] = "-----"; char freq_str[20] = "---"; char peak_str[20] = "---"; if (freq >= 0) { - snprintf(note_str, sizeof(note_str), "%c%c%c", dir<0 ? '>' : ' ', note, dir>0 ? '<' : ' '); + snprintf(note_str, sizeof(note_str), "%c%s%c", dir<0 ? '>' : ' ', note, dir>0 ? '<' : ' '); snprintf(freq_str, sizeof(freq_str), "%.2f Hz", freq); snprintf(peak_str, sizeof(peak_str), "%.2f Hz", peak_freq); } @@ -106,34 +215,38 @@ static void update_output(double freq, char note, int dir) static void find_note(double freq) { - int i, index = 0, dir = 0; - char note = '?'; - - /* E, A, D, G, B, e */ - const double notes[] = { INT_MIN, 82.41, 110.00, 146.83, 196.00, 246.94, 329.63, INT_MAX }; - const char *note_str = "?EADGBe?"; - - for (i=0; i<7; i++) { - if (freq > notes[i+1]) { - continue; - } - if (freq > (notes[i] + notes[i+1])/2) { - note = note_str[i+1]; - dir = -1; - index = i+1; - } else { - note = note_str[i]; - dir = +1; - index = i; + int note = 0, dir = 0; + + if (freq <= note_table[1].freq) { + note = 1; + dir = -1; + } else if (freq >= note_table[ARRAY_SIZE(note_table)-1].freq) { + note = ARRAY_SIZE(note_table) - 1; + dir = +1; + } else { + unsigned int i; + for (i=0; i<ARRAY_SIZE(note_table)-2; i++) { + double center; + if (freq > note_table[i+1].freq) { + continue; + } + center = (note_table[i].freq + note_table[i+1].freq) / 2; + if (freq > center) { + note = i+1; + dir = -1; + } else { + note = i; + dir = +1; + } + break; } - break; } - if (fabs(freq - notes[index]) < ACCURACY) { + if (fabs(freq - note_table[note].freq) < ACCURACY) { dir = 0; } - update_output(freq, note, dir); + update_output(freq, note_table[note].name, dir); } static void calculate_magnitudes() |