From 839411b1fddceb5f730e7fcf5114dd29f2b54b9d Mon Sep 17 00:00:00 2001
From: David Westgate <davidjwestgate@gmail.com>
Date: Fri, 15 Nov 2024 15:50:44 -0800
Subject: [PATCH] tuner code

---
 code/tuner/main.py | 85 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 code/tuner/main.py

diff --git a/code/tuner/main.py b/code/tuner/main.py
new file mode 100644
index 0000000..567a72e
--- /dev/null
+++ b/code/tuner/main.py
@@ -0,0 +1,85 @@
+import string
+from typing import Any
+from scipy.io import wavfile as wav
+import numpy as np
+import sounddevice as sd
+import math
+import sys
+
+print("Tuner exercise")
+SAMPLE_RATE = 44100
+CHUNK = 2048
+QUIET_THRESHOLD = 0.01
+A4 = 440
+DEBUG = True
+NOTES = "A B♭/A♯ B C D♭/C♯ D E♭/D♯ E F F♯/G♭ G A♭/G♯".split()
+
+
+def calculate_note(frequency):
+    if frequency > 0:
+        note_num = round(math.log2(frequency / 440) * 12)
+        octave = math.floor(4 + note_num / 12)
+        rel_note = note_num % 12
+        note = NOTES[rel_note]
+        return f"{note}{octave}"
+    return 0
+
+
+def dominant_frequency(data, samplerate):
+    windowed_data = data * np.hanning(len(data))
+    fft_result = np.fft.rfft(windowed_data)
+    fft_magnitude = np.abs(fft_result)
+    freqs = np.fft.rfftfreq(len(windowed_data), 1 / samplerate)
+    peak_idx = np.argmax(fft_magnitude)
+    dominant_freq = freqs[peak_idx]
+    return dominant_freq
+
+
+def calculate_rms(data):
+    return np.sqrt(np.mean(data**2))
+
+
+def audio_callback(indata: np.ndarray, frames: int, time: Any, status: Any):
+    if status:
+        print(f"Status: {status}")
+    rms = calculate_rms(indata)
+
+    if rms > QUIET_THRESHOLD:
+        mono_data = np.mean(indata, axis=1)
+        frequency = dominant_frequency(mono_data, SAMPLE_RATE)
+        out =  f"\r{calculate_note(frequency)}"
+
+        if DEBUG: out += f" Dominant Frequency: {frequency:.2f} Hz (RMS: {rms:.3f})"
+        sys.stdout.write(out)
+        sys.stdout.flush()
+    else:
+        pass
+
+
+if DEBUG:
+    print(sd.query_devices())
+
+
+try:
+    stream = sd.InputStream(
+        device=15,
+        callback=audio_callback,
+        samplerate=SAMPLE_RATE,
+        channels=1,
+        blocksize=CHUNK,
+    )
+    stream.start()
+    if DEBUG:
+        print("channels? ", stream.channels)
+        print("device? ", stream.device)
+        print("active? ", stream.active)
+    while True:
+        pass
+except KeyboardInterrupt:
+    print("Audio recording stopped.")
+
+finally:
+    print("Stream closed.")
+
+# https://python-sounddevice.readthedocs.io/en/0.5.1/examples.html#plot-microphone-signal-s-in-real-time
+# https://github.com/mzucker/python-tuner/blob/master/tuner.py