1 /*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 // Mac OS X - specific FFTFrame implementation
30
31 #include "config.h"
32
33 #if ENABLE(WEB_AUDIO)
34
35 #include "FFTFrame.h"
36
37 namespace WebCore {
38
39 const int kMaxFFTPow2Size = 24;
40
41 FFTSetup* FFTFrame::fftSetups = 0;
42
43 // Normal constructor: allocates for a given fftSize
FFTFrame(unsigned fftSize)44 FFTFrame::FFTFrame(unsigned fftSize)
45 : m_realData(fftSize)
46 , m_imagData(fftSize)
47 {
48 m_FFTSize = fftSize;
49 m_log2FFTSize = static_cast<unsigned>(log2(fftSize));
50
51 // We only allow power of two
52 ASSERT(1UL << m_log2FFTSize == m_FFTSize);
53
54 // Lazily create and share fftSetup with other frames
55 m_FFTSetup = fftSetupForSize(fftSize);
56
57 // Setup frame data
58 m_frame.realp = m_realData.data();
59 m_frame.imagp = m_imagData.data();
60 }
61
62 // Creates a blank/empty frame (interpolate() must later be called)
FFTFrame()63 FFTFrame::FFTFrame()
64 : m_realData(0)
65 , m_imagData(0)
66 {
67 // Later will be set to correct values when interpolate() is called
68 m_frame.realp = 0;
69 m_frame.imagp = 0;
70
71 m_FFTSize = 0;
72 m_log2FFTSize = 0;
73 }
74
75 // Copy constructor
FFTFrame(const FFTFrame & frame)76 FFTFrame::FFTFrame(const FFTFrame& frame)
77 : m_FFTSize(frame.m_FFTSize)
78 , m_log2FFTSize(frame.m_log2FFTSize)
79 , m_FFTSetup(frame.m_FFTSetup)
80 , m_realData(frame.m_FFTSize)
81 , m_imagData(frame.m_FFTSize)
82 {
83 // Setup frame data
84 m_frame.realp = m_realData.data();
85 m_frame.imagp = m_imagData.data();
86
87 // Copy/setup frame data
88 unsigned nbytes = sizeof(float) * m_FFTSize;
89 memcpy(realData(), frame.m_frame.realp, nbytes);
90 memcpy(imagData(), frame.m_frame.imagp, nbytes);
91 }
92
~FFTFrame()93 FFTFrame::~FFTFrame()
94 {
95 }
96
multiply(const FFTFrame & frame)97 void FFTFrame::multiply(const FFTFrame& frame)
98 {
99 FFTFrame& frame1 = *this;
100 const FFTFrame& frame2 = frame;
101
102 float* realP1 = frame1.realData();
103 float* imagP1 = frame1.imagData();
104 const float* realP2 = frame2.realData();
105 const float* imagP2 = frame2.imagData();
106
107 // Scale accounts for vecLib's peculiar scaling
108 // This ensures the right scaling all the way back to inverse FFT
109 float scale = 0.5f;
110
111 // Multiply packed DC/nyquist component
112 realP1[0] *= scale * realP2[0];
113 imagP1[0] *= scale * imagP2[0];
114
115 // Multiply the rest, skipping packed DC/Nyquist components
116 DSPSplitComplex sc1 = frame1.dspSplitComplex();
117 sc1.realp++;
118 sc1.imagp++;
119
120 DSPSplitComplex sc2 = frame2.dspSplitComplex();
121 sc2.realp++;
122 sc2.imagp++;
123
124 unsigned halfSize = m_FFTSize / 2;
125
126 // Complex multiply
127 vDSP_zvmul(&sc1, 1, &sc2, 1, &sc1, 1, halfSize - 1, 1 /* normal multiplication */);
128
129 // We've previously scaled the packed part, now scale the rest.....
130 vDSP_vsmul(sc1.realp, 1, &scale, sc1.realp, 1, halfSize - 1);
131 vDSP_vsmul(sc1.imagp, 1, &scale, sc1.imagp, 1, halfSize - 1);
132 }
133
doFFT(float * data)134 void FFTFrame::doFFT(float* data)
135 {
136 vDSP_ctoz((DSPComplex*)data, 2, &m_frame, 1, m_FFTSize / 2);
137 vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_FORWARD);
138 }
139
doInverseFFT(float * data)140 void FFTFrame::doInverseFFT(float* data)
141 {
142 vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_INVERSE);
143 vDSP_ztoc(&m_frame, 1, (DSPComplex*)data, 2, m_FFTSize / 2);
144
145 // Do final scaling so that x == IFFT(FFT(x))
146 float scale = 0.5f / m_FFTSize;
147 vDSP_vsmul(data, 1, &scale, data, 1, m_FFTSize);
148 }
149
fftSetupForSize(unsigned fftSize)150 FFTSetup FFTFrame::fftSetupForSize(unsigned fftSize)
151 {
152 if (!fftSetups) {
153 fftSetups = (FFTSetup*)malloc(sizeof(FFTSetup) * kMaxFFTPow2Size);
154 memset(fftSetups, 0, sizeof(FFTSetup) * kMaxFFTPow2Size);
155 }
156
157 int pow2size = static_cast<int>(log2(fftSize));
158 ASSERT(pow2size < kMaxFFTPow2Size);
159 if (!fftSetups[pow2size])
160 fftSetups[pow2size] = vDSP_create_fftsetup(pow2size, FFT_RADIX2);
161
162 return fftSetups[pow2size];
163 }
164
initialize()165 void FFTFrame::initialize()
166 {
167 }
168
cleanup()169 void FFTFrame::cleanup()
170 {
171 if (!fftSetups)
172 return;
173
174 for (int i = 0; i < kMaxFFTPow2Size; ++i) {
175 if (fftSetups[i])
176 vDSP_destroy_fftsetup(fftSetups[i]);
177 }
178
179 free(fftSetups);
180 fftSetups = 0;
181 }
182
realData() const183 float* FFTFrame::realData() const
184 {
185 return m_frame.realp;
186 }
187
imagData() const188 float* FFTFrame::imagData() const
189 {
190 return m_frame.imagp;
191 }
192
193 } // namespace WebCore
194
195 #endif // ENABLE(WEB_AUDIO)
196