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,int num_frames,int num_input_channels,int num_output_channels,float * const * output)22 void LappedTransform::BlockThunk::ProcessBlock(const float* const* input,
23 int num_frames,
24 int num_input_channels,
25 int num_output_channels,
26 float* const* output) {
27 CHECK_EQ(num_input_channels, parent_->in_channels_);
28 CHECK_EQ(num_output_channels, parent_->out_channels_);
29 CHECK_EQ(parent_->block_length_, num_frames);
30
31 for (int 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 int block_length = RealFourier::ComplexLength(
39 RealFourier::FftOrder(num_frames));
40 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 (int 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(int in_channels,int out_channels,int chunk_length,const float * window,int block_length,int shift_amount,Callback * callback)55 LappedTransform::LappedTransform(int in_channels, int out_channels,
56 int chunk_length, const float* window,
57 int block_length, int shift_amount,
58 Callback* callback)
59 : blocker_callback_(this),
60 in_channels_(in_channels),
61 out_channels_(out_channels),
62 block_length_(block_length),
63 chunk_length_(chunk_length),
64 block_processor_(callback),
65 blocker_(
66 chunk_length_, block_length_, in_channels_, out_channels_, window,
67 shift_amount, &blocker_callback_),
68 fft_(RealFourier::Create(RealFourier::FftOrder(block_length_))),
69 cplx_length_(RealFourier::ComplexLength(fft_->order())),
70 real_buf_(in_channels, block_length_, RealFourier::kFftBufferAlignment),
71 cplx_pre_(in_channels, cplx_length_, RealFourier::kFftBufferAlignment),
72 cplx_post_(out_channels, cplx_length_, RealFourier::kFftBufferAlignment) {
73 CHECK(in_channels_ > 0 && out_channels_ > 0);
74 CHECK_GT(block_length_, 0);
75 CHECK_GT(chunk_length_, 0);
76 CHECK(block_processor_);
77
78 // block_length_ power of 2?
79 CHECK_EQ(0, block_length_ & (block_length_ - 1));
80 }
81
ProcessChunk(const float * const * in_chunk,float * const * out_chunk)82 void LappedTransform::ProcessChunk(const float* const* in_chunk,
83 float* const* out_chunk) {
84 blocker_.ProcessChunk(in_chunk, chunk_length_, in_channels_, out_channels_,
85 out_chunk);
86 }
87
88 } // namespace webrtc
89
90