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// Unit tests for BufferLevelFilter class. 12 13#include "webrtc/modules/audio_coding/neteq/buffer_level_filter.h" 14 15#include <math.h> // Access to pow function. 16 17#include "testing/gtest/include/gtest/gtest.h" 18 19namespace webrtc { 20 21TEST(BufferLevelFilter, CreateAndDestroy) { 22 BufferLevelFilter* filter = new BufferLevelFilter(); 23 EXPECT_EQ(0, filter->filtered_current_level()); 24 delete filter; 25} 26 27TEST(BufferLevelFilter, ConvergenceTest) { 28 BufferLevelFilter filter; 29 for (int times = 10; times <= 50; times += 10) { 30 for (int value = 100; value <= 200; value += 10) { 31 filter.Reset(); 32 filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256. 33 std::ostringstream ss; 34 ss << "times = " << times << ", value = " << value; 35 SCOPED_TRACE(ss.str()); // Print out the parameter values on failure. 36 for (int i = 0; i < times; ++i) { 37 filter.Update(value, 0 /* time_stretched_samples */, 38 160 /* packet_len_samples */); 39 } 40 // Expect the filtered value to be (theoretically) 41 // (1 - (251/256) ^ |times|) * |value|. 42 double expected_value_double = 43 (1 - pow(251.0 / 256.0, times)) * value; 44 int expected_value = static_cast<int>(expected_value_double); 45 // filtered_current_level() returns the value in Q8. 46 // The actual value may differ slightly from the expected value due to 47 // intermediate-stage rounding errors in the filter implementation. 48 // This is why we have to use EXPECT_NEAR with a tolerance of +/-1. 49 EXPECT_NEAR(expected_value, filter.filtered_current_level() >> 8, 1); 50 } 51 } 52} 53 54// Verify that target buffer level impacts on the filter convergence. 55TEST(BufferLevelFilter, FilterFactor) { 56 BufferLevelFilter filter; 57 // Update 10 times with value 100. 58 const int kTimes = 10; 59 const int kValue = 100; 60 61 filter.SetTargetBufferLevel(3); // Makes filter coefficient 252/256. 62 for (int i = 0; i < kTimes; ++i) { 63 filter.Update(kValue, 0 /* time_stretched_samples */, 64 160 /* packet_len_samples */); 65 } 66 // Expect the filtered value to be 67 // (1 - (252/256) ^ |kTimes|) * |kValue|. 68 int expected_value = 14; 69 // filtered_current_level() returns the value in Q8. 70 EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8); 71 72 filter.Reset(); 73 filter.SetTargetBufferLevel(7); // Makes filter coefficient 253/256. 74 for (int i = 0; i < kTimes; ++i) { 75 filter.Update(kValue, 0 /* time_stretched_samples */, 76 160 /* packet_len_samples */); 77 } 78 // Expect the filtered value to be 79 // (1 - (253/256) ^ |kTimes|) * |kValue|. 80 expected_value = 11; 81 // filtered_current_level() returns the value in Q8. 82 EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8); 83 84 filter.Reset(); 85 filter.SetTargetBufferLevel(8); // Makes filter coefficient 254/256. 86 for (int i = 0; i < kTimes; ++i) { 87 filter.Update(kValue, 0 /* time_stretched_samples */, 88 160 /* packet_len_samples */); 89 } 90 // Expect the filtered value to be 91 // (1 - (254/256) ^ |kTimes|) * |kValue|. 92 expected_value = 7; 93 // filtered_current_level() returns the value in Q8. 94 EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8); 95} 96 97 98TEST(BufferLevelFilter, TimeStretchedSamples) { 99 BufferLevelFilter filter; 100 filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256. 101 // Update 10 times with value 100. 102 const int kTimes = 10; 103 const int kValue = 100; 104 const int kPacketSizeSamples = 160; 105 const int kNumPacketsStretched = 2; 106 const int kTimeStretchedSamples = kNumPacketsStretched * kPacketSizeSamples; 107 for (int i = 0; i < kTimes; ++i) { 108 // Packet size set to 0. Do not expect the parameter 109 // |kTimeStretchedSamples| to have any effect. 110 filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */); 111 } 112 // Expect the filtered value to be 113 // (1 - (251/256) ^ |kTimes|) * |kValue|. 114 const int kExpectedValue = 17; 115 // filtered_current_level() returns the value in Q8. 116 EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8); 117 118 // Update filter again, now with non-zero value for packet length. 119 // Set the current filtered value to be the input, in order to isolate the 120 // impact of |kTimeStretchedSamples|. 121 filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples, 122 kPacketSizeSamples); 123 EXPECT_EQ(kExpectedValue - kNumPacketsStretched, 124 filter.filtered_current_level() >> 8); 125 // Try negative value and verify that we come back to the previous result. 126 filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples, 127 kPacketSizeSamples); 128 EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8); 129} 130 131TEST(BufferLevelFilter, TimeStretchedSamplesNegativeUnevenFrames) { 132 BufferLevelFilter filter; 133 filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256. 134 // Update 10 times with value 100. 135 const int kTimes = 10; 136 const int kValue = 100; 137 const int kPacketSizeSamples = 160; 138 const int kTimeStretchedSamples = -3.1415 * kPacketSizeSamples; 139 for (int i = 0; i < kTimes; ++i) { 140 // Packet size set to 0. Do not expect the parameter 141 // |kTimeStretchedSamples| to have any effect. 142 filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */); 143 } 144 // Expect the filtered value to be 145 // (1 - (251/256) ^ |kTimes|) * |kValue|. 146 const int kExpectedValue = 17; 147 // filtered_current_level() returns the value in Q8. 148 EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8); 149 150 // Update filter again, now with non-zero value for packet length. 151 // Set the current filtered value to be the input, in order to isolate the 152 // impact of |kTimeStretchedSamples|. 153 filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples, 154 kPacketSizeSamples); 155 EXPECT_EQ(21, filter.filtered_current_level() >> 8); 156 // Try negative value and verify that we come back to the previous result. 157 filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples, 158 kPacketSizeSamples); 159 EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8); 160} 161 162} // namespace webrtc 163