Consolidate decimate functions in a single file

friture/delay_estimator.py

@@ -21,47 +21,14 @@
 from numpy import argmax
 import numpy
 from numpy.fft import rfft, irfft
-from .filter import decimate
+from .signal.decimate import decimate_multiple, decimate_multiple_filtic
 from friture import generated_filters
 from .ringbuffer import RingBuffer
 
 from friture.audiobackend import SAMPLING_RATE
 
 DEFAULT_DELAYRANGE = 1  # default delay range is 1 second
 
-
-def subsampler(Ndec, bdec, adec, x, zis):
-    x_dec = x
-
-    # FIXME problems when x is smaller than filter coeff
-
-    # do not run on empty arrays, otherwise bad artefacts on the output !!
-    if x.size == 0:
-        return x, zis
-
-    if zis is None:
-        for i in range(Ndec):
-            x_dec, zf = decimate(bdec, adec, x_dec)
-        return x_dec, None
-    else:
-        zfs = []
-        for i, zi in zip(list(range(Ndec)), zis):
-            x_dec, zf = decimate(bdec, adec, x_dec, zi=zi)
-            # zf can be reused to restart the filter
-            zfs += [zf]
-        return x_dec, zfs
-
-# build a proper array of zero initial conditions to start the subsampler
-
-
-def subsampler_filtic(Ndec, bdec, adec):
-    zfs = []
-    for i in range(Ndec):
-        l = max(len(bdec), len(adec)) - 1
-        zfs += [numpy.zeros(l)]
-    return zfs
-
-
 def generalized_cross_correlation(d0, d1):
     # substract the means
     # (in order to get a normalized cross-correlation at the end)
@@ -160,8 +127,8 @@ def __init__(self, parent=None):
         [self.bdec, self.adec] = generated_filters.PARAMS['dec']
         self.bdec = numpy.array(self.bdec)
         self.adec = numpy.array(self.adec)
-        self.zfs0 = subsampler_filtic(self.Ndec, self.bdec, self.adec)
-        self.zfs1 = subsampler_filtic(self.Ndec, self.bdec, self.adec)
+        self.zfs0 = decimate_multiple_filtic(self.Ndec, self.bdec, self.adec)
+        self.zfs1 = decimate_multiple_filtic(self.Ndec, self.bdec, self.adec)
 
         # ringbuffers for the subsampled data
         self.ringbuffer0 = RingBuffer()
@@ -193,8 +160,8 @@ def handle_new_data(self, floatdata):
             x0 = floatdata[0, :]
             x1 = floatdata[1, :]
             # subsample them
-            x0_dec, self.zfs0 = subsampler(self.Ndec, self.bdec, self.adec, x0, self.zfs0)
-            x1_dec, self.zfs1 = subsampler(self.Ndec, self.bdec, self.adec, x1, self.zfs1)
+            x0_dec, self.zfs0 = decimate_multiple(self.Ndec, self.bdec, self.adec, x0, self.zfs0)
+            x1_dec, self.zfs1 = decimate_multiple(self.Ndec, self.bdec, self.adec, x1, self.zfs1)
             # push to a 1-second ring buffer
             x0_dec.shape = (1, x0_dec.size)
             x1_dec.shape = (1, x1_dec.size)

friture/filter.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 from numpy import arange, sqrt, zeros, array
 from .lfilter import pyx_lfilter_float64_1D
+from .signal.decimate import decimate
 
 NOCTAVE = 9
 
@@ -114,20 +115,7 @@ def octave_filter_bank_decimation(blow, alow, forward, feedback, x, zis):
 
     return y, dec, zfs
 
-
-def decimate(bdec, adec, x, zi):
-    if len(x) == 0:
-        raise Exception("Filter input is too small")
-
-    # could use a polyphase decimator here
-    x_dec, zf = pyx_lfilter_float64_1D(bdec, adec, x, zi)
-
-    x_dec = x_dec[::2]
-    return x_dec, zf
-
 # build a proper array of zero initial conditions to start the filters
-
-
 def octave_filter_bank_decimation_filtic(blow, alow, forward, feedback):
     bands_per_octave = len(forward)
     zfs = []

friture/longlevels.py

@@ -26,9 +26,7 @@
                                          DEFAULT_LEVEL_MAX)
 from friture.audioproc import audioproc
 from friture.timeplot import TimePlot
-from .filter import decimate
-from friture import generated_filters
-from friture.exp_smoothing_conv import pyx_exp_smoothed_value
+from .signal.decimate import decimate
 from .ringbuffer import RingBuffer
 from .lfilter import pyx_lfilter_float64_1D
 

friture/signal/decimate.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright (C) 2018 Timothée Lecomte
+
+# This file is part of Friture.
+#
+# Friture is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as published by
+# the Free Software Foundation.
+#
+# Friture is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Friture.  If not, see <http://www.gnu.org/licenses/>.
+
+import numpy
+from ..lfilter import pyx_lfilter_float64_1D
+
+def decimate(bdec, adec, x, zi):
+    if len(x) == 0:
+        raise Exception("Filter input is too small")
+
+    # could use a polyphase decimator here
+    x_dec, zf = pyx_lfilter_float64_1D(bdec, adec, x, zi)
+
+    x_dec = x_dec[::2]
+    return x_dec, zf
+
+# decimate 'Ndec' times
+def decimate_multiple(Ndec, bdec, adec, x, zis):
+    x_dec = x
+
+    # FIXME problems when x is smaller than filter coeff
+
+    # do not run on empty arrays, otherwise output contains artifacts
+    if x.size == 0:
+        return x, zis
+
+    if zis is None:
+        for i in range(Ndec):
+            x_dec, zf = decimate(bdec, adec, x_dec)
+        return x_dec, None
+    else:
+        zfs = []
+        for i, zi in zip(list(range(Ndec)), zis):
+            x_dec, zf = decimate(bdec, adec, x_dec, zi=zi)
+            # zf can be reused to restart the filter
+            zfs += [zf]
+        return x_dec, zfs
+
+# build a proper array of zero initial conditions to start the subsampler
+def decimate_multiple_filtic(Ndec, bdec, adec):
+    zfs = []
+    for i in range(Ndec):
+        l = max(len(bdec), len(adec)) - 1
+        zfs += [numpy.zeros(l)]
+    return zfs

sandbox/delay.py

@@ -21,10 +21,9 @@
 import numpy
 import numpy as np
 from numpy.fft import rfft, irfft, fft, ifft
-from friture.filter import decimate
 from friture import generated_filters
-from friture.ringbuffer import RingBuffer
-from friture.delay_estimator import subsampler, subsampler_filtic, DEFAULT_DELAYRANGE
+from friture.delay_estimator import DEFAULT_DELAYRANGE
+from friture.signal.decimate import decimate_multiple, decimate_multiple_filtic
 from scipy.io import wavfile
 import matplotlib.pyplot as plt
 
@@ -106,8 +105,8 @@ def main():
     Ndec = 2
     subsampled_sampling_rate = SAMPLING_RATE/2**(Ndec)
     [bdec, adec] = generated_filters.PARAMS['dec']
-    zfs0 = subsampler_filtic(Ndec, bdec, adec)
-    zfs1 = subsampler_filtic(Ndec, bdec, adec)
+    zfs0 = decimate_multiple_filtic(Ndec, bdec, adec)
+    zfs1 = decimate_multiple_filtic(Ndec, bdec, adec)
 
     delayrange_s = DEFAULT_DELAYRANGE # confidence range
 
@@ -116,9 +115,9 @@ def main():
     x1 = m
     #subsample them
     print("subsampling x0")
-    x0_dec, zfs0 = subsampler(Ndec, bdec, adec, x0, zfs0)
+    x0_dec, zfs0 = decimate_multiple(Ndec, bdec, adec, x0, zfs0)
     print("subsampling x1")
-    x1_dec, zfs1 = subsampler(Ndec, bdec, adec, x1, zfs1)
+    x1_dec, zfs1 = decimate_multiple(Ndec, bdec, adec, x1, zfs1)
 
     time = 2*delayrange_s
     length = time*subsampled_sampling_rate