tools: analyze-wav.py: Increase coverage threshold

Increase the coverage threshold for detecting audio glitches. The
threshold defines how many frequencies need to be "active" to mark a
point as a glitch. The increase of the parameter decreases a chance for
a false positive where the spectrogram is "blurry", but doesn't contain
glitches.

Signed-off-by: Pawel Langowski <pawelx.langowski@intel.com>

Author: PLangowski

tools/analyze-wav.py

@@ -50,6 +50,7 @@ def detect_vertical_lines(wav_file):
     dtype = get_dtype(info.subtype.lower())
 
     data, sr = sf.read(wav_file, dtype=dtype)
+    print(f"Sample rate: {sr}")
     if data.ndim > 1:
         data = data[:, 0]
     # Remove silence at the beginning and end
@@ -85,7 +86,7 @@ def detect_vertical_lines(wav_file):
     # If the normalised frequency is greater than the threshold, mark it as active.
     active_freqs = Sxx_norm > freq_threshold
     coverage = np.sum(active_freqs, axis=0) / active_freqs.shape[0]
-    coverage_threshold = 0.8
+    coverage_threshold = 0.95
     # If coverage exceeds threshold, mark as vertical line.
     vertical_lines = np.where(coverage > coverage_threshold)[0]
     print(f"Detected possible glitches at time indices: {vertical_lines + trim_samples + non_silent[0]}")