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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 | |
21 float MicLevel2Gain(int gain_range_db, int level) { | |
22 return (level - 127.0f) / 128.0f * gain_range_db / 2; | |
23 } | |
24 | |
25 float Db2Linear(float db) { | |
26 return powf(10.0f, db / 20.0f); | |
27 } | |
28 | |
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 | |
43 void ApplyGain(float gain_db, float last_gain_db, AudioFrame* frame) { | |
44 ApplyGainLinear(Db2Linear(gain_db), Db2Linear(last_gain_db), frame); | |
45 } | |
46 | |
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 | |
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 | |
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