1 // Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the LICENSE file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8
9 #include <algorithm>
10 #include <array>
11 #include <cmath>
12 #include <fstream>
13
14 #include "absl/flags/flag.h"
15 #include "absl/flags/parse.h"
16 #include "common_audio/include/audio_util.h"
17 #include "common_audio/wav_file.h"
18 #include "rtc_base/logging.h"
19
20 ABSL_FLAG(std::string, i, "", "Input wav file");
21 ABSL_FLAG(std::string, oc, "", "Config output file");
22 ABSL_FLAG(std::string, ol, "", "Levels output file");
23 ABSL_FLAG(float, a, 5.f, "Attack (ms)");
24 ABSL_FLAG(float, d, 20.f, "Decay (ms)");
25 ABSL_FLAG(int, f, 10, "Frame length (ms)");
26
27 namespace webrtc {
28 namespace test {
29 namespace {
30
31 constexpr int kMaxSampleRate = 48000;
32 constexpr uint8_t kMaxFrameLenMs = 30;
33 constexpr size_t kMaxFrameLen = kMaxFrameLenMs * kMaxSampleRate / 1000;
34
35 const double kOneDbReduction = DbToRatio(-1.0);
36
main(int argc,char * argv[])37 int main(int argc, char* argv[]) {
38 absl::ParseCommandLine(argc, argv);
39 // Check parameters.
40 if (absl::GetFlag(FLAGS_f) < 1 || absl::GetFlag(FLAGS_f) > kMaxFrameLenMs) {
41 RTC_LOG(LS_ERROR) << "Invalid frame length (min: 1, max: " << kMaxFrameLenMs
42 << ")";
43 return 1;
44 }
45 if (absl::GetFlag(FLAGS_a) < 0 || absl::GetFlag(FLAGS_d) < 0) {
46 RTC_LOG(LS_ERROR) << "Attack and decay must be non-negative";
47 return 1;
48 }
49
50 // Open wav input file and check properties.
51 const std::string input_file = absl::GetFlag(FLAGS_i);
52 const std::string config_output_file = absl::GetFlag(FLAGS_oc);
53 const std::string levels_output_file = absl::GetFlag(FLAGS_ol);
54 WavReader wav_reader(input_file);
55 if (wav_reader.num_channels() != 1) {
56 RTC_LOG(LS_ERROR) << "Only mono wav files supported";
57 return 1;
58 }
59 if (wav_reader.sample_rate() > kMaxSampleRate) {
60 RTC_LOG(LS_ERROR) << "Beyond maximum sample rate (" << kMaxSampleRate
61 << ")";
62 return 1;
63 }
64
65 // Map from milliseconds to samples.
66 const size_t audio_frame_length = rtc::CheckedDivExact(
67 absl::GetFlag(FLAGS_f) * wav_reader.sample_rate(), 1000);
68 auto time_const = [](double c) {
69 return std::pow(kOneDbReduction, absl::GetFlag(FLAGS_f) / c);
70 };
71 const float attack =
72 absl::GetFlag(FLAGS_a) == 0.0 ? 0.0 : time_const(absl::GetFlag(FLAGS_a));
73 const float decay =
74 absl::GetFlag(FLAGS_d) == 0.0 ? 0.0 : time_const(absl::GetFlag(FLAGS_d));
75
76 // Write config to file.
77 std::ofstream out_config(config_output_file);
78 out_config << "{"
79 "'frame_len_ms': "
80 << absl::GetFlag(FLAGS_f)
81 << ", "
82 "'attack_ms': "
83 << absl::GetFlag(FLAGS_a)
84 << ", "
85 "'decay_ms': "
86 << absl::GetFlag(FLAGS_d) << "}\n";
87 out_config.close();
88
89 // Measure level frame-by-frame.
90 std::ofstream out_levels(levels_output_file, std::ofstream::binary);
91 std::array<int16_t, kMaxFrameLen> samples;
92 float level_prev = 0.f;
93 while (true) {
94 // Process frame.
95 const auto read_samples =
96 wav_reader.ReadSamples(audio_frame_length, samples.data());
97 if (read_samples < audio_frame_length)
98 break; // EOF.
99
100 // Frame peak level.
101 std::transform(samples.begin(), samples.begin() + audio_frame_length,
102 samples.begin(), [](int16_t s) { return std::abs(s); });
103 const int16_t peak_level = *std::max_element(
104 samples.cbegin(), samples.cbegin() + audio_frame_length);
105 const float level_curr = static_cast<float>(peak_level) / 32768.f;
106
107 // Temporal smoothing.
108 auto smooth = [&level_prev, &level_curr](float c) {
109 return (1.0 - c) * level_curr + c * level_prev;
110 };
111 level_prev = smooth(level_curr > level_prev ? attack : decay);
112
113 // Write output.
114 out_levels.write(reinterpret_cast<const char*>(&level_prev), sizeof(float));
115 }
116 out_levels.close();
117
118 return 0;
119 }
120
121 } // namespace
122 } // namespace test
123 } // namespace webrtc
124
main(int argc,char * argv[])125 int main(int argc, char* argv[]) {
126 return webrtc::test::main(argc, argv);
127 }
128