1 /*
2 * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "modules/audio_processing/utility/pffft_wrapper.h"
12
13 #include "rtc_base/checks.h"
14 #include "third_party/pffft/src/pffft.h"
15
16 namespace webrtc {
17 namespace {
18
GetBufferSize(size_t fft_size,Pffft::FftType fft_type)19 size_t GetBufferSize(size_t fft_size, Pffft::FftType fft_type) {
20 return fft_size * (fft_type == Pffft::FftType::kReal ? 1 : 2);
21 }
22
AllocatePffftBuffer(size_t size)23 float* AllocatePffftBuffer(size_t size) {
24 return static_cast<float*>(pffft_aligned_malloc(size * sizeof(float)));
25 }
26
27 } // namespace
28
FloatBuffer(size_t fft_size,FftType fft_type)29 Pffft::FloatBuffer::FloatBuffer(size_t fft_size, FftType fft_type)
30 : size_(GetBufferSize(fft_size, fft_type)),
31 data_(AllocatePffftBuffer(size_)) {}
32
~FloatBuffer()33 Pffft::FloatBuffer::~FloatBuffer() {
34 pffft_aligned_free(data_);
35 }
36
GetConstView() const37 rtc::ArrayView<const float> Pffft::FloatBuffer::GetConstView() const {
38 return {data_, size_};
39 }
40
GetView()41 rtc::ArrayView<float> Pffft::FloatBuffer::GetView() {
42 return {data_, size_};
43 }
44
Pffft(size_t fft_size,FftType fft_type)45 Pffft::Pffft(size_t fft_size, FftType fft_type)
46 : fft_size_(fft_size),
47 fft_type_(fft_type),
48 pffft_status_(pffft_new_setup(
49 fft_size_,
50 fft_type == Pffft::FftType::kReal ? PFFFT_REAL : PFFFT_COMPLEX)),
51 scratch_buffer_(
52 AllocatePffftBuffer(GetBufferSize(fft_size_, fft_type_))) {
53 RTC_DCHECK(pffft_status_);
54 RTC_DCHECK(scratch_buffer_);
55 }
56
~Pffft()57 Pffft::~Pffft() {
58 pffft_destroy_setup(pffft_status_);
59 pffft_aligned_free(scratch_buffer_);
60 }
61
IsValidFftSize(size_t fft_size,FftType fft_type)62 bool Pffft::IsValidFftSize(size_t fft_size, FftType fft_type) {
63 if (fft_size == 0) {
64 return false;
65 }
66 // PFFFT only supports transforms for inputs of length N of the form
67 // N = (2^a)*(3^b)*(5^c) where b >=0 and c >= 0 and a >= 5 for the real FFT
68 // and a >= 4 for the complex FFT.
69 constexpr int kFactors[] = {2, 3, 5};
70 int factorization[] = {0, 0, 0};
71 int n = static_cast<int>(fft_size);
72 for (int i = 0; i < 3; ++i) {
73 while (n % kFactors[i] == 0) {
74 n = n / kFactors[i];
75 factorization[i]++;
76 }
77 }
78 int a_min = (fft_type == Pffft::FftType::kReal) ? 5 : 4;
79 return factorization[0] >= a_min && n == 1;
80 }
81
IsSimdEnabled()82 bool Pffft::IsSimdEnabled() {
83 return pffft_simd_size() > 1;
84 }
85
CreateBuffer() const86 std::unique_ptr<Pffft::FloatBuffer> Pffft::CreateBuffer() const {
87 // Cannot use make_unique from absl because Pffft is the only friend of
88 // Pffft::FloatBuffer.
89 std::unique_ptr<Pffft::FloatBuffer> buffer(
90 new Pffft::FloatBuffer(fft_size_, fft_type_));
91 return buffer;
92 }
93
ForwardTransform(const FloatBuffer & in,FloatBuffer * out,bool ordered)94 void Pffft::ForwardTransform(const FloatBuffer& in,
95 FloatBuffer* out,
96 bool ordered) {
97 RTC_DCHECK_EQ(in.size(), GetBufferSize(fft_size_, fft_type_));
98 RTC_DCHECK_EQ(in.size(), out->size());
99 RTC_DCHECK(scratch_buffer_);
100 if (ordered) {
101 pffft_transform_ordered(pffft_status_, in.const_data(), out->data(),
102 scratch_buffer_, PFFFT_FORWARD);
103 } else {
104 pffft_transform(pffft_status_, in.const_data(), out->data(),
105 scratch_buffer_, PFFFT_FORWARD);
106 }
107 }
108
BackwardTransform(const FloatBuffer & in,FloatBuffer * out,bool ordered)109 void Pffft::BackwardTransform(const FloatBuffer& in,
110 FloatBuffer* out,
111 bool ordered) {
112 RTC_DCHECK_EQ(in.size(), GetBufferSize(fft_size_, fft_type_));
113 RTC_DCHECK_EQ(in.size(), out->size());
114 RTC_DCHECK(scratch_buffer_);
115 if (ordered) {
116 pffft_transform_ordered(pffft_status_, in.const_data(), out->data(),
117 scratch_buffer_, PFFFT_BACKWARD);
118 } else {
119 pffft_transform(pffft_status_, in.const_data(), out->data(),
120 scratch_buffer_, PFFFT_BACKWARD);
121 }
122 }
123
FrequencyDomainConvolve(const FloatBuffer & fft_x,const FloatBuffer & fft_y,FloatBuffer * out,float scaling)124 void Pffft::FrequencyDomainConvolve(const FloatBuffer& fft_x,
125 const FloatBuffer& fft_y,
126 FloatBuffer* out,
127 float scaling) {
128 RTC_DCHECK_EQ(fft_x.size(), GetBufferSize(fft_size_, fft_type_));
129 RTC_DCHECK_EQ(fft_x.size(), fft_y.size());
130 RTC_DCHECK_EQ(fft_x.size(), out->size());
131 pffft_zconvolve_accumulate(pffft_status_, fft_x.const_data(),
132 fft_y.const_data(), out->data(), scaling);
133 }
134
135 } // namespace webrtc
136