1 /*
2 * Copyright (c) 2012 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/tools/agc/test_utils.h"
12
13 #include <cmath>
14
15 #include <algorithm>
16
17 #include "webrtc/modules/include/module_common_types.h"
18
19 namespace webrtc {
20
MicLevel2Gain(int gain_range_db,int level)21 float MicLevel2Gain(int gain_range_db, int level) {
22 return (level - 127.0f) / 128.0f * gain_range_db / 2;
23 }
24
Db2Linear(float db)25 float Db2Linear(float db) {
26 return powf(10.0f, db / 20.0f);
27 }
28
ApplyGainLinear(float gain,float last_gain,AudioFrame * frame)29 void ApplyGainLinear(float gain, float last_gain, AudioFrame* frame) {
30 const size_t frame_length =
31 frame->samples_per_channel_ * frame->num_channels_;
32 // Smooth the transition between gain levels across the frame.
33 float smoothed_gain = last_gain;
34 float gain_step = (gain - last_gain) / (frame_length - 1);
35 for (size_t i = 0; i < frame_length; ++i) {
36 smoothed_gain += gain_step;
37 float sample = std::floor(frame->data_[i] * smoothed_gain + 0.5);
38 sample = std::max(std::min(32767.0f, sample), -32768.0f);
39 frame->data_[i] = static_cast<int16_t>(sample);
40 }
41 }
42
ApplyGain(float gain_db,float last_gain_db,AudioFrame * frame)43 void ApplyGain(float gain_db, float last_gain_db, AudioFrame* frame) {
44 ApplyGainLinear(Db2Linear(gain_db), Db2Linear(last_gain_db), frame);
45 }
46
SimulateMic(int gain_range_db,int mic_level,int last_mic_level,AudioFrame * frame)47 void SimulateMic(int gain_range_db, int mic_level, int last_mic_level,
48 AudioFrame* frame) {
49 assert(mic_level >= 0 && mic_level <= 255);
50 assert(last_mic_level >= 0 && last_mic_level <= 255);
51 ApplyGain(MicLevel2Gain(gain_range_db, mic_level),
52 MicLevel2Gain(gain_range_db, last_mic_level),
53 frame);
54 }
55
SimulateMic(int gain_map[255],int mic_level,int last_mic_level,AudioFrame * frame)56 void SimulateMic(int gain_map[255], int mic_level, int last_mic_level,
57 AudioFrame* frame) {
58 assert(mic_level >= 0 && mic_level <= 255);
59 assert(last_mic_level >= 0 && last_mic_level <= 255);
60 ApplyGain(gain_map[mic_level], gain_map[last_mic_level], frame);
61 }
62
63 } // namespace webrtc
64
65