Set bit depth to 32

24 would be sufficient, but there's no such thing as int24 in numpy. So
that's a bit trickier.

README.md

@@ -16,6 +16,7 @@ SampleScanner is a command-line tool to turn MIDI instruments (usually hardware)
  - Clipping detection at sample time
  - 100% Python to enable cross-platform compatibility
  - Has been known to work in Windows, Mac OS and Linux
+ - Currently 32-bit recording only (must be supported by audio interface)
 
 ## Installation
 

lib/constants.py

@@ -1,9 +1,9 @@
 import numpy
 
 neg80point8db = 0.00009120108393559096
-bit_depth = 16
+bit_depth = 32
 default_silence_threshold = (neg80point8db * (2 ** (bit_depth - 1))) * 4
-NUMPY_DTYPE = numpy.int16 if bit_depth == 16 else numpy.int24
+NUMPY_DTYPE = numpy.int16 if bit_depth == 16 else numpy.int32
 SAMPLE_RATE = 48000
 
 EXIT_ON_CLIPPING = True

lib/record.py

@@ -9,7 +9,8 @@
 
 CHUNK_SIZE = 1024
 NUM_CHANNELS = 2
-FORMAT = pyaudio.paInt16 if bit_depth == 16 else pyaudio.paInt24
+PA_FORMAT = pyaudio.paInt16 if bit_depth == 16 else pyaudio.paInt32
+FORMAT_CHAR = 'h' if bit_depth == 16 else 'i'
 
 if not sys.platform == "win32":
     GO_UP = "\033[F"
@@ -87,7 +88,7 @@ def record(
     input_device_index = get_input_device_index(p, audio_interface_name)
 
     stream = p.open(
-        format=FORMAT,
+        format=PA_FORMAT,
         channels=NUM_CHANNELS,
         rate=sample_rate,
         input=True,
@@ -216,7 +217,7 @@ def record(
     for chunk in data:
         r = numpy.concatenate((r, chunk), axis=1)
 
-    sample_width = p.get_sample_size(FORMAT)
+    sample_width = p.get_sample_size(PA_FORMAT)
     stream.stop_stream()
     stream.close()
     p.terminate()
@@ -258,7 +259,7 @@ def save_to_file(path, sample_width, data, sample_rate=SAMPLE_RATE):
     write_chunk_size = 512
     for chunk_start in range(0, len(flattened), write_chunk_size):
         chunk = flattened[chunk_start:chunk_start + write_chunk_size]
-        packstring = '<' + ('h' * len(chunk))
+        packstring = '<' + (FORMAT_CHAR * len(chunk))
         wf.writeframes(pack(packstring, *chunk))
     wf.close()
 

tests/utils_test.py

@@ -3,15 +3,15 @@
 
 def test_sample_value_to_db():
     assert str(sample_value_to_db(0)) == "-inf"
-    assert sample_value_to_db(1) == -90.30899869919435
+    assert sample_value_to_db(1) == -186.63859731166835
 
 
 def test_percent_to_db():
-    assert percent_to_db(0.000030518) == -90.30887862628592
+    assert percent_to_db(4.656612873077392e-10) == -186.63859731166835
     assert str(percent_to_db(0)) == "-inf"
 
 
 def test_dbfs_as_percent():
-    minimum_16_bit_dbfs = -90.30899869919435
+    minimum_16_bit_dbfs = -186.63859731166835
     assert dbfs_as_percent(minimum_16_bit_dbfs) == 0
     assert dbfs_as_percent(0) == 1