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 #if OS(MACOSX)
36
37 #include "platform/audio/FFTFrame.h"
38
39 #include "platform/audio/VectorMath.h"
40
41 namespace WebCore {
42
43 const int kMaxFFTPow2Size = 24;
44
45 FFTSetup* FFTFrame::fftSetups = 0;
46
47 // Normal constructor: allocates for a given fftSize
FFTFrame(unsigned fftSize)48 FFTFrame::FFTFrame(unsigned fftSize)
49 : m_realData(fftSize)
50 , m_imagData(fftSize)
51 {
52 m_FFTSize = fftSize;
53 m_log2FFTSize = static_cast<unsigned>(log2(fftSize));
54
55 // We only allow power of two
56 ASSERT(1UL << m_log2FFTSize == m_FFTSize);
57
58 // Lazily create and share fftSetup with other frames
59 m_FFTSetup = fftSetupForSize(fftSize);
60
61 // Setup frame data
62 m_frame.realp = m_realData.data();
63 m_frame.imagp = m_imagData.data();
64 }
65
66 // Creates a blank/empty frame (interpolate() must later be called)
FFTFrame()67 FFTFrame::FFTFrame()
68 : m_realData(0)
69 , m_imagData(0)
70 {
71 // Later will be set to correct values when interpolate() is called
72 m_frame.realp = 0;
73 m_frame.imagp = 0;
74
75 m_FFTSize = 0;
76 m_log2FFTSize = 0;
77 }
78
79 // Copy constructor
FFTFrame(const FFTFrame & frame)80 FFTFrame::FFTFrame(const FFTFrame& frame)
81 : m_FFTSize(frame.m_FFTSize)
82 , m_log2FFTSize(frame.m_log2FFTSize)
83 , m_FFTSetup(frame.m_FFTSetup)
84 , m_realData(frame.m_FFTSize)
85 , m_imagData(frame.m_FFTSize)
86 {
87 // Setup frame data
88 m_frame.realp = m_realData.data();
89 m_frame.imagp = m_imagData.data();
90
91 // Copy/setup frame data
92 unsigned nbytes = sizeof(float) * m_FFTSize;
93 memcpy(realData(), frame.m_frame.realp, nbytes);
94 memcpy(imagData(), frame.m_frame.imagp, nbytes);
95 }
96
~FFTFrame()97 FFTFrame::~FFTFrame()
98 {
99 }
100
doFFT(const float * data)101 void FFTFrame::doFFT(const float* data)
102 {
103 AudioFloatArray scaledData(m_FFTSize);
104 // veclib fft returns a result that is twice as large as would be expected. Compensate for that
105 // by scaling the input by half so the FFT has the correct scaling.
106 float scale = 0.5f;
107 VectorMath::vsmul(data, 1, &scale, scaledData.data(), 1, m_FFTSize);
108
109 vDSP_ctoz((DSPComplex*)scaledData.data(), 2, &m_frame, 1, m_FFTSize / 2);
110 vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_FORWARD);
111 }
112
doInverseFFT(float * data)113 void FFTFrame::doInverseFFT(float* data)
114 {
115 vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_INVERSE);
116 vDSP_ztoc(&m_frame, 1, (DSPComplex*)data, 2, m_FFTSize / 2);
117
118 // Do final scaling so that x == IFFT(FFT(x))
119 float scale = 1.0f / m_FFTSize;
120 vDSP_vsmul(data, 1, &scale, data, 1, m_FFTSize);
121 }
122
fftSetupForSize(unsigned fftSize)123 FFTSetup FFTFrame::fftSetupForSize(unsigned fftSize)
124 {
125 if (!fftSetups) {
126 fftSetups = (FFTSetup*)malloc(sizeof(FFTSetup) * kMaxFFTPow2Size);
127 memset(fftSetups, 0, sizeof(FFTSetup) * kMaxFFTPow2Size);
128 }
129
130 int pow2size = static_cast<int>(log2(fftSize));
131 ASSERT(pow2size < kMaxFFTPow2Size);
132 if (!fftSetups[pow2size])
133 fftSetups[pow2size] = vDSP_create_fftsetup(pow2size, FFT_RADIX2);
134
135 return fftSetups[pow2size];
136 }
137
initialize()138 void FFTFrame::initialize()
139 {
140 }
141
cleanup()142 void FFTFrame::cleanup()
143 {
144 if (!fftSetups)
145 return;
146
147 for (int i = 0; i < kMaxFFTPow2Size; ++i) {
148 if (fftSetups[i])
149 vDSP_destroy_fftsetup(fftSetups[i]);
150 }
151
152 free(fftSetups);
153 fftSetups = 0;
154 }
155
realData() const156 float* FFTFrame::realData() const
157 {
158 return m_frame.realp;
159 }
160
imagData() const161 float* FFTFrame::imagData() const
162 {
163 return m_frame.imagp;
164 }
165
166 } // namespace WebCore
167
168 #endif // #if OS(MACOSX)
169
170 #endif // ENABLE(WEB_AUDIO)
171