eml-mel-filterbank: Commandline tool for generating Mel filterbanks

examples/mel-filterbank.py

@@ -0,0 +1,77 @@
+
+"""
+eml-mel-filterbank: Generate C code for a mel filterbank
+
+Can be used with eml_sparse_filterbank()
+"""
+
+import argparse
+import textwrap
+
+import librosa
+
+import emlearn.signal
+
+
+def mel_filterbank(args, name):
+    mel_basis = librosa.filters.mel(sr=args.samplerate, n_fft=args.fft, n_mels=args.bands,
+                                    fmin=args.fmin, fmax=args.fmax, htk=args.htk)
+    sparse = emlearn.signal.sparse_filterbank(mel_basis)
+    gen = emlearn.signal.sparse_filterbank_serialize(sparse, name=name)
+
+    w = textwrap.wrap(gen, args.linewrap, replace_whitespace=False)
+    wrapped = '\n'.join(w)
+    return wrapped
+
+
+def parse(args=None):
+    parser = argparse.ArgumentParser(description='Generate lookup table for window functions')
+    a = parser.add_argument
+
+    a('--bands', type=str, default=32,
+      help='Number of mel bands')
+    a('--fft', type=int, default=1024,
+      help='Number of coefficients in FFT')
+    a('--samplerate', type=int, default=16000,
+      help='Samplerate used')
+
+    a('--fmin', type=int, default=0,
+      help='Frequency of lowest band. Default: 0')
+    a('--fmax', type=int, default=None,
+      help='Frequency of highest band. Default: samplerate/2')
+    a('--htk', type=bool, default=False,
+      help='Use HTK style filter spacing')
+    a('--normalize', type=bool, default=True,
+      help='Use HTK style filter spacing')
+
+    a('--name', type=str, default='',
+      help='Output file. Default: ')
+    a('--out', type=str, default='',
+      help='Output file. Default: $name.h')
+    a('--linewrap', type=int, default=70,
+      help='Maximum width of lines')
+
+    parsed = parser.parse_args(args)
+    return parsed
+
+
+def main():
+    args = parse()
+    out = args.out
+    name = args.name
+    if not name:
+        name = '_'.join(['mel', str(args.fft), str(args.bands)])
+    if not out:
+        out = name+'.h'
+
+    preamble = '// This file was generated with emlearn using eml-window-function\n\n'
+    gen = mel_filterbank(args, name)
+    wrapped = preamble + gen + '\n\n'
+
+    with open(out, 'w') as f:
+        f.write(wrapped)
+    print('Wrote to', out)
+
+
+if __name__ == '__main__':
+    main()

examples/window-function.py

@@ -18,24 +18,24 @@
 
 
 def parse(args=None):
-        parser = argparse.ArgumentParser(description='Generate lookup table for window functions')
-        a = parser.add_argument
-
-        a('--window', type=str, default='hann',
-          help='Window function to use. Supported: \n' + '|'.join(known_window_types))
-        a('--length', type=int, default=1024,
-          help='Number of coefficients in window')
-        a('--symmetric', default=False, action='store_true',
-          help='Whether to use a symmetric window. Defaults to False, normal for FFT')
-        a('--name', type=str, default='',
-          help='Name of the generate C array')
-        a('--out', type=str, default='',
-          help='Output file. Default: $name.h')
-        a('--linewrap', type=int, default=70,
-          help='Maximum width of lines')
-
-        parsed = parser.parse_args(args)
-        return parsed
+    parser = argparse.ArgumentParser(description='Generate lookup table for window functions')
+    a = parser.add_argument
+
+    a('--window', type=str, default='hann',
+      help='Window function to use. Supported: \n' + '|'.join(known_window_types))
+    a('--length', type=int, default=1024,
+      help='Number of coefficients in window')
+    a('--symmetric', default=False, action='store_true',
+      help='Whether to use a symmetric window. Defaults to False, normal for FFT')
+    a('--name', type=str, default='',
+      help='Name of the generate C array')
+    a('--out', type=str, default='',
+      help='Output file. Default: $name.h')
+    a('--linewrap', type=int, default=70,
+      help='Maximum width of lines')
+
+    parsed = parser.parse_args(args)
+    return parsed
 
 
 def window_function(name, window_type, length, fft_mode, linewrap):

setup.py

@@ -161,6 +161,7 @@ def read_readme():
     packages=['emlearn'],
     scripts={
         'examples/window-function.py': 'eml-window-function',
+        'examples/mel-filterbank.py': 'eml-mel-filterbank',
     },
     ext_modules=ext_modules,
     include_package_data=True,