diff tests/TestPhaseVocoder.cpp @ 347:e3dedded9c4d

Merge from pvoc branch

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/TestPhaseVocoder.cpp	Fri Oct 04 16:43:44 2013 +0100
@@ -0,0 +1,193 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+#include "dsp/phasevocoder/PhaseVocoder.h"
+
+#include "base/Window.h"
+
+#include <iostream>
+
+using std::cerr;
+using std::endl;
+
+#define BOOST_TEST_DYN_LINK
+#define BOOST_TEST_MAIN
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_AUTO_TEST_SUITE(TestFFT)
+
+#define COMPARE_CONST(a, n) \
+    for (int cmp_i = 0; cmp_i < (int)(sizeof(a)/sizeof(a[0])); ++cmp_i) { \
+        BOOST_CHECK_SMALL(a[cmp_i] - n, 1e-7);				\
+    }
+
+#define COMPARE_ARRAY(a, b)						\
+    for (int cmp_i = 0; cmp_i < (int)(sizeof(a)/sizeof(a[0])); ++cmp_i) { \
+        BOOST_CHECK_SMALL(a[cmp_i] - b[cmp_i], 1e-7);			\
+    }
+
+#define COMPARE_ARRAY_EXACT(a, b)						\
+    for (int cmp_i = 0; cmp_i < (int)(sizeof(a)/sizeof(a[0])); ++cmp_i) { \
+        BOOST_CHECK_EQUAL(a[cmp_i], b[cmp_i]);			\
+    }
+
+BOOST_AUTO_TEST_CASE(fullcycle)
+{
+    // Cosine with one cycle exactly equal to pvoc hopsize. This is
+    // pretty much the most trivial case -- in fact it's
+    // indistinguishable from totally silent input (in the phase
+    // values) because the measured phases are zero throughout.
+
+    // We aren't windowing the input frame because (for once) it
+    // actually *is* just a short part of a continuous infinite
+    // sinusoid.
+
+    double frame[] = { 1, 0, -1, 0, 1, 0, -1, 0 };
+
+    PhaseVocoder pvoc(8, 4);
+
+    // Make these arrays one element too long at each end, so as to
+    // test for overruns. For frame size 8, we expect 8/2+1 = 5
+    // mag/phase pairs.
+    double mag[]   = { 999, 999, 999, 999, 999, 999, 999 };
+    double phase[] = { 999, 999, 999, 999, 999, 999, 999 };
+    double unw[]   = { 999, 999, 999, 999, 999, 999, 999 };
+
+    pvoc.processTimeDomain(frame, mag + 1, phase + 1, unw + 1);
+
+    double magExpected0[] = { 999, 0, 0, 4, 0, 0, 999 };
+    COMPARE_ARRAY_EXACT(mag, magExpected0);
+
+    double phaseExpected0[] = { 999, 0, 0, 0, 0, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected0);
+
+    double unwExpected0[] = { 999, 0, 0, 0, 0, 0, 999 };
+    COMPARE_ARRAY(unw, unwExpected0);
+
+    pvoc.processTimeDomain(frame, mag + 1, phase + 1, unw + 1);
+
+    double magExpected1[] = { 999, 0, 0, 4, 0, 0, 999 };
+    COMPARE_ARRAY_EXACT(mag, magExpected1);
+
+    double phaseExpected1[] = { 999, 0, 0, 0, 0, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected1);
+
+    // Derivation of unwrapped values:
+    // 
+    // * Bin 0 (DC) always has phase 0 and expected phase 0
+    //
+    // * Bin 1 has expected phase pi (the hop size is half a cycle at
+    //   its frequency), but measured phase 0 (because there is no
+    //   signal in that bin). So it has phase error -pi, which is
+    //   mapped into (-pi,pi] range as pi, giving an unwrapped phase
+    //   of 2*pi.
+    //  
+    // * Bin 2 has expected phase 2*pi, measured phase 0, hence error
+    //   0 and unwrapped phase 2*pi.
+    //
+    // * Bin 3 is like bin 1: it has expected phase 3*pi, measured
+    //   phase 0, so phase error -pi and unwrapped phase 4*pi.
+    //
+    // * Bin 4 (Nyquist) has expected phase 4*pi, measured phase 0,
+    //   hence error 0 and unwrapped phase 4*pi.
+
+    double unwExpected1[] = { 999, 0, 2*M_PI, 2*M_PI, 4*M_PI, 4*M_PI, 999 };
+    COMPARE_ARRAY(unw, unwExpected1);
+
+    pvoc.processTimeDomain(frame, mag + 1, phase + 1, unw + 1);
+
+    double magExpected2[] = { 999, 0, 0, 4, 0, 0, 999 };
+    COMPARE_ARRAY_EXACT(mag, magExpected2);
+
+    double phaseExpected2[] = { 999, 0, 0, 0, 0, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected2);
+
+    double unwExpected2[] = { 999, 0, 4*M_PI, 4*M_PI, 8*M_PI, 8*M_PI, 999 };
+    COMPARE_ARRAY(unw, unwExpected2);
+}
+
+BOOST_AUTO_TEST_CASE(overlapping)
+{
+    // Sine (i.e. cosine starting at phase -pi/2) starting with the
+    // first sample, introducing a cosine of half the frequency
+    // starting at the fourth sample, i.e. the second hop. The cosine
+    // is introduced "by magic", i.e. it doesn't appear in the second
+    // half of the first frame (it would have quite strange effects on
+    // the first frame if it did).
+
+    double data[32] = { // 3 x 8-sample frames which we pretend are overlapping
+	0, 1, 0, -1, 0, 1, 0, -1,
+	1, 1.70710678, 0, -1.70710678, -1, 0.29289322, 0, -0.29289322,
+	-1, 0.29289322, 0, -0.29289322, 1, 1.70710678, 0, -1.70710678,
+    };
+
+    PhaseVocoder pvoc(8, 4);
+
+    // Make these arrays one element too long at each end, so as to
+    // test for overruns. For frame size 8, we expect 8/2+1 = 5
+    // mag/phase pairs.
+    double mag[]   = { 999, 999, 999, 999, 999, 999, 999 };
+    double phase[] = { 999, 999, 999, 999, 999, 999, 999 };
+    double unw[]   = { 999, 999, 999, 999, 999, 999, 999 };
+
+    pvoc.processTimeDomain(data, mag + 1, phase + 1, unw + 1);
+
+    double magExpected0[] = { 999, 0, 0, 4, 0, 0, 999 };
+    COMPARE_ARRAY(mag, magExpected0);
+
+    double phaseExpected0[] = { 999, 0, 0, -M_PI/2 , 0, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected0);
+
+    double unwExpected0[] = { 999, 0, 0, -M_PI/2, 0, 0, 999 };
+    COMPARE_ARRAY(unw, unwExpected0);
+
+    pvoc.processTimeDomain(data + 8, mag + 1, phase + 1, unw + 1);
+
+    double magExpected1[] = { 999, 0, 4, 4, 0, 0, 999 };
+    COMPARE_ARRAY(mag, magExpected1);
+
+    // Derivation of unwrapped values:
+    // 
+    // * Bin 0 (DC) always has phase 0 and expected phase 0
+    //
+    // * Bin 1 has a new signal, a cosine starting with phase 0. But
+    //   because of the "FFT shift" which the phase vocoder carries
+    //   out to place zero phase in the centre of the (usually
+    //   windowed) frame, and because a single cycle at this frequency
+    //   spans the whole frame, this bin actually has measured phase
+    //   of either pi or -pi. (The shift doesn't affect those
+    //   higher-frequency bins whose signals fit exact multiples of a
+    //   cycle into a frame.) This maps into (-pi,pi] as pi, which
+    //   matches the expected phase, hence unwrapped phase is also pi.
+    //
+    // * Bin 2 has expected phase 3pi/2 (being the previous measured
+    //   phase of -pi/2 plus advance of 2pi). It has the same measured
+    //   phase as last time around, -pi/2, which is consistent with
+    //   the expected phase, so the unwrapped phase is 3pi/2.
+    //!!!
+    // * Bin 3 is a bit of a puzzle -- it has an effectively zero
+    //   magnitude but a non-zero measured phase. Spectral leakage?
+    //
+    // * Bin 4 (Nyquist) has expected phase 4*pi, measured phase 0,
+    //   hence error 0 and unwrapped phase 4*pi.
+
+    double phaseExpected1[] = { 999, 0, -M_PI, -M_PI/2, M_PI, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected1);
+
+    double unwExpected1[] = { 999, 0, M_PI, 3*M_PI/2, 3*M_PI, 4*M_PI, 999 };
+    COMPARE_ARRAY(unw, unwExpected1);
+
+    pvoc.processTimeDomain(data + 16, mag + 1, phase + 1, unw + 1);
+
+    double magExpected2[] = { 999, 0, 4, 4, 0, 0, 999 };
+    COMPARE_ARRAY(mag, magExpected2);
+
+    double phaseExpected2[] = { 999, 0, 0, -M_PI/2, 0, 0, 999 };
+    COMPARE_ARRAY(phase, phaseExpected2);
+
+    double unwExpected2[] = { 999, 0, 2*M_PI, 7*M_PI/2, 6*M_PI, 8*M_PI, 999 };
+    COMPARE_ARRAY(unw, unwExpected2);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+