1 /*
2 * Copyright (c) 2014 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 "webrtc/common_audio/lapped_transform.h"
12
13 #include <algorithm>
14 #include <cstdlib>
15 #include <cstring>
16
17 #include "webrtc/base/checks.h"
18 #include "webrtc/common_audio/real_fourier.h"
19
20 namespace webrtc {
21
ProcessBlock(const float * const * input,size_t num_frames,size_t num_input_channels,size_t num_output_channels,float * const * output)22 void LappedTransform::BlockThunk::ProcessBlock(const float* const* input,
23 size_t num_frames,
24 size_t num_input_channels,
25 size_t num_output_channels,
26 float* const* output) {
27 RTC_CHECK_EQ(num_input_channels, parent_->num_in_channels_);
28 RTC_CHECK_EQ(num_output_channels, parent_->num_out_channels_);
29 RTC_CHECK_EQ(parent_->block_length_, num_frames);
30
31 for (size_t i = 0; i < num_input_channels; ++i) {
32 memcpy(parent_->real_buf_.Row(i), input[i],
33 num_frames * sizeof(*input[0]));
34 parent_->fft_->Forward(parent_->real_buf_.Row(i),
35 parent_->cplx_pre_.Row(i));
36 }
37
38 size_t block_length = RealFourier::ComplexLength(
39 RealFourier::FftOrder(num_frames));
40 RTC_CHECK_EQ(parent_->cplx_length_, block_length);
41 parent_->block_processor_->ProcessAudioBlock(parent_->cplx_pre_.Array(),
42 num_input_channels,
43 parent_->cplx_length_,
44 num_output_channels,
45 parent_->cplx_post_.Array());
46
47 for (size_t i = 0; i < num_output_channels; ++i) {
48 parent_->fft_->Inverse(parent_->cplx_post_.Row(i),
49 parent_->real_buf_.Row(i));
50 memcpy(output[i], parent_->real_buf_.Row(i),
51 num_frames * sizeof(*input[0]));
52 }
53 }
54
LappedTransform(size_t num_in_channels,size_t num_out_channels,size_t chunk_length,const float * window,size_t block_length,size_t shift_amount,Callback * callback)55 LappedTransform::LappedTransform(size_t num_in_channels,
56 size_t num_out_channels,
57 size_t chunk_length,
58 const float* window,
59 size_t block_length,
60 size_t shift_amount,
61 Callback* callback)
62 : blocker_callback_(this),
63 num_in_channels_(num_in_channels),
64 num_out_channels_(num_out_channels),
65 block_length_(block_length),
66 chunk_length_(chunk_length),
67 block_processor_(callback),
68 blocker_(chunk_length_,
69 block_length_,
70 num_in_channels_,
71 num_out_channels_,
72 window,
73 shift_amount,
74 &blocker_callback_),
75 fft_(RealFourier::Create(RealFourier::FftOrder(block_length_))),
76 cplx_length_(RealFourier::ComplexLength(fft_->order())),
77 real_buf_(num_in_channels,
78 block_length_,
79 RealFourier::kFftBufferAlignment),
80 cplx_pre_(num_in_channels,
81 cplx_length_,
82 RealFourier::kFftBufferAlignment),
83 cplx_post_(num_out_channels,
84 cplx_length_,
85 RealFourier::kFftBufferAlignment) {
86 RTC_CHECK(num_in_channels_ > 0 && num_out_channels_ > 0);
87 RTC_CHECK_GT(block_length_, 0u);
88 RTC_CHECK_GT(chunk_length_, 0u);
89 RTC_CHECK(block_processor_);
90
91 // block_length_ power of 2?
92 RTC_CHECK_EQ(0u, block_length_ & (block_length_ - 1));
93 }
94
ProcessChunk(const float * const * in_chunk,float * const * out_chunk)95 void LappedTransform::ProcessChunk(const float* const* in_chunk,
96 float* const* out_chunk) {
97 blocker_.ProcessChunk(in_chunk, chunk_length_, num_in_channels_,
98 num_out_channels_, out_chunk);
99 }
100
101 } // namespace webrtc
102