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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 <algorithm> | |
| 12 | |
| 13 #include "webrtc/base/rate_statistics.h" | |
| 14 #include "webrtc/test/gtest.h" | |
| 15 | |
| 16 namespace { | |
| 17 | |
| 18 using webrtc::RateStatistics; | |
| 19 | |
| 20 const int64_t kWindowMs = 500; | |
| 21 | |
| 22 class RateStatisticsTest : public ::testing::Test { | |
| 23 protected: | |
| 24 RateStatisticsTest() : stats_(kWindowMs, 8000) {} | |
| 25 RateStatistics stats_; | |
| 26 }; | |
| 27 | |
| 28 TEST_F(RateStatisticsTest, TestStrictMode) { | |
| 29 int64_t now_ms = 0; | |
| 30 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 31 | |
| 32 const uint32_t kPacketSize = 1500u; | |
| 33 const uint32_t kExpectedRateBps = kPacketSize * 1000 * 8; | |
| 34 | |
| 35 // Single data point is not enough for valid estimate. | |
| 36 stats_.Update(kPacketSize, now_ms++); | |
| 37 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 38 | |
| 39 // Expecting 1200 kbps since the window is initially kept small and grows as | |
| 40 // we have more data. | |
| 41 stats_.Update(kPacketSize, now_ms); | |
| 42 EXPECT_EQ(kExpectedRateBps, *stats_.Rate(now_ms)); | |
| 43 | |
| 44 stats_.Reset(); | |
| 45 // Expecting 0 after init. | |
| 46 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 47 | |
| 48 const int kInterval = 10; | |
| 49 for (int i = 0; i < 100000; ++i) { | |
| 50 if (i % kInterval == 0) | |
| 51 stats_.Update(kPacketSize, now_ms); | |
| 52 | |
| 53 // Approximately 1200 kbps expected. Not exact since when packets | |
| 54 // are removed we will jump 10 ms to the next packet. | |
| 55 if (i > kInterval) { | |
| 56 rtc::Optional<uint32_t> rate = stats_.Rate(now_ms); | |
| 57 EXPECT_TRUE(static_cast<bool>(rate)); | |
| 58 uint32_t samples = i / kInterval + 1; | |
| 59 uint64_t total_bits = samples * kPacketSize * 8; | |
| 60 uint32_t rate_bps = static_cast<uint32_t>((1000 * total_bits) / (i + 1)); | |
| 61 EXPECT_NEAR(rate_bps, *rate, 22000u); | |
| 62 } | |
| 63 now_ms += 1; | |
| 64 } | |
| 65 now_ms += kWindowMs; | |
| 66 // The window is 2 seconds. If nothing has been received for that time | |
| 67 // the estimate should be 0. | |
| 68 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 69 } | |
| 70 | |
| 71 TEST_F(RateStatisticsTest, IncreasingThenDecreasingBitrate) { | |
| 72 int64_t now_ms = 0; | |
| 73 stats_.Reset(); | |
| 74 // Expecting 0 after init. | |
| 75 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 76 | |
| 77 stats_.Update(1000, ++now_ms); | |
| 78 const uint32_t kExpectedBitrate = 8000000; | |
| 79 // 1000 bytes per millisecond until plateau is reached. | |
| 80 int prev_error = kExpectedBitrate; | |
| 81 rtc::Optional<uint32_t> bitrate; | |
| 82 while (++now_ms < 10000) { | |
| 83 stats_.Update(1000, now_ms); | |
| 84 bitrate = stats_.Rate(now_ms); | |
| 85 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 86 int error = kExpectedBitrate - *bitrate; | |
| 87 error = std::abs(error); | |
| 88 // Expect the estimation error to decrease as the window is extended. | |
| 89 EXPECT_LE(error, prev_error + 1); | |
| 90 prev_error = error; | |
| 91 } | |
| 92 // Window filled, expect to be close to 8000000. | |
| 93 EXPECT_EQ(kExpectedBitrate, *bitrate); | |
| 94 | |
| 95 // 1000 bytes per millisecond until 10-second mark, 8000 kbps expected. | |
| 96 while (++now_ms < 10000) { | |
| 97 stats_.Update(1000, now_ms); | |
| 98 bitrate = stats_.Rate(now_ms); | |
| 99 EXPECT_EQ(kExpectedBitrate, *bitrate); | |
| 100 } | |
| 101 | |
| 102 // Zero bytes per millisecond until 0 is reached. | |
| 103 while (++now_ms < 20000) { | |
| 104 stats_.Update(0, now_ms); | |
| 105 rtc::Optional<uint32_t> new_bitrate = stats_.Rate(now_ms); | |
| 106 if (static_cast<bool>(new_bitrate) && *new_bitrate != *bitrate) { | |
| 107 // New bitrate must be lower than previous one. | |
| 108 EXPECT_LT(*new_bitrate, *bitrate); | |
| 109 } else { | |
| 110 // 0 kbps expected. | |
| 111 EXPECT_EQ(0u, *new_bitrate); | |
| 112 break; | |
| 113 } | |
| 114 bitrate = new_bitrate; | |
| 115 } | |
| 116 | |
| 117 // Zero bytes per millisecond until 20-second mark, 0 kbps expected. | |
| 118 while (++now_ms < 20000) { | |
| 119 stats_.Update(0, now_ms); | |
| 120 EXPECT_EQ(0u, *stats_.Rate(now_ms)); | |
| 121 } | |
| 122 } | |
| 123 | |
| 124 TEST_F(RateStatisticsTest, ResetAfterSilence) { | |
| 125 int64_t now_ms = 0; | |
| 126 stats_.Reset(); | |
| 127 // Expecting 0 after init. | |
| 128 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 129 | |
| 130 const uint32_t kExpectedBitrate = 8000000; | |
| 131 // 1000 bytes per millisecond until the window has been filled. | |
| 132 int prev_error = kExpectedBitrate; | |
| 133 rtc::Optional<uint32_t> bitrate; | |
| 134 while (++now_ms < 10000) { | |
| 135 stats_.Update(1000, now_ms); | |
| 136 bitrate = stats_.Rate(now_ms); | |
| 137 if (bitrate) { | |
| 138 int error = kExpectedBitrate - *bitrate; | |
| 139 error = std::abs(error); | |
| 140 // Expect the estimation error to decrease as the window is extended. | |
| 141 EXPECT_LE(error, prev_error + 1); | |
| 142 prev_error = error; | |
| 143 } | |
| 144 } | |
| 145 // Window filled, expect to be close to 8000000. | |
| 146 EXPECT_EQ(kExpectedBitrate, *bitrate); | |
| 147 | |
| 148 now_ms += kWindowMs + 1; | |
| 149 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 150 stats_.Update(1000, now_ms); | |
| 151 ++now_ms; | |
| 152 stats_.Update(1000, now_ms); | |
| 153 // We expect two samples of 1000 bytes, and that the bitrate is measured over | |
| 154 // 500 ms, i.e. 2 * 8 * 1000 / 0.500 = 32000. | |
| 155 EXPECT_EQ(32000u, *stats_.Rate(now_ms)); | |
| 156 | |
| 157 // Reset, add the same samples again. | |
| 158 stats_.Reset(); | |
| 159 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 160 stats_.Update(1000, now_ms); | |
| 161 ++now_ms; | |
| 162 stats_.Update(1000, now_ms); | |
| 163 // We expect two samples of 1000 bytes, and that the bitrate is measured over | |
| 164 // 2 ms (window size has been reset) i.e. 2 * 8 * 1000 / 0.002 = 8000000. | |
| 165 EXPECT_EQ(kExpectedBitrate, *stats_.Rate(now_ms)); | |
| 166 } | |
| 167 | |
| 168 TEST_F(RateStatisticsTest, HandlesChangingWindowSize) { | |
| 169 int64_t now_ms = 0; | |
| 170 stats_.Reset(); | |
| 171 | |
| 172 // Sanity test window size. | |
| 173 EXPECT_TRUE(stats_.SetWindowSize(kWindowMs, now_ms)); | |
| 174 EXPECT_FALSE(stats_.SetWindowSize(kWindowMs + 1, now_ms)); | |
| 175 EXPECT_FALSE(stats_.SetWindowSize(0, now_ms)); | |
| 176 EXPECT_TRUE(stats_.SetWindowSize(1, now_ms)); | |
| 177 EXPECT_TRUE(stats_.SetWindowSize(kWindowMs, now_ms)); | |
| 178 | |
| 179 // Fill the buffer at a rate of 1 byte / millisecond (8 kbps). | |
| 180 const int kBatchSize = 10; | |
| 181 for (int i = 0; i <= kWindowMs; i += kBatchSize) | |
| 182 stats_.Update(kBatchSize, now_ms += kBatchSize); | |
| 183 EXPECT_EQ(static_cast<uint32_t>(8000), *stats_.Rate(now_ms)); | |
| 184 | |
| 185 // Halve the window size, rate should stay the same. | |
| 186 EXPECT_TRUE(stats_.SetWindowSize(kWindowMs / 2, now_ms)); | |
| 187 EXPECT_EQ(static_cast<uint32_t>(8000), *stats_.Rate(now_ms)); | |
| 188 | |
| 189 // Double the window size again, rate should stay the same. (As the window | |
| 190 // won't actually expand until new bit and bobs fall into it. | |
| 191 EXPECT_TRUE(stats_.SetWindowSize(kWindowMs, now_ms)); | |
| 192 EXPECT_EQ(static_cast<uint32_t>(8000), *stats_.Rate(now_ms)); | |
| 193 | |
| 194 // Fill the now empty half with bits it twice the rate. | |
| 195 for (int i = 0; i < kWindowMs / 2; i += kBatchSize) | |
| 196 stats_.Update(kBatchSize * 2, now_ms += kBatchSize); | |
| 197 | |
| 198 // Rate should have increase be 50%. | |
| 199 EXPECT_EQ(static_cast<uint32_t>((8000 * 3) / 2), *stats_.Rate(now_ms)); | |
| 200 } | |
| 201 | |
| 202 TEST_F(RateStatisticsTest, RespectsWindowSizeEdges) { | |
| 203 int64_t now_ms = 0; | |
| 204 stats_.Reset(); | |
| 205 // Expecting 0 after init. | |
| 206 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 207 | |
| 208 // One byte per ms, using one big sample. | |
| 209 stats_.Update(kWindowMs, now_ms); | |
| 210 now_ms += kWindowMs - 2; | |
| 211 // Shouldn't work! (Only one sample, not full window size.) | |
| 212 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 213 | |
| 214 // Window size should be full, and the single data point should be accepted. | |
| 215 ++now_ms; | |
| 216 rtc::Optional<uint32_t> bitrate = stats_.Rate(now_ms); | |
| 217 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 218 EXPECT_EQ(1000 * 8u, *bitrate); | |
| 219 | |
| 220 // Add another, now we have twice the bitrate. | |
| 221 stats_.Update(kWindowMs, now_ms); | |
| 222 bitrate = stats_.Rate(now_ms); | |
| 223 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 224 EXPECT_EQ(2 * 1000 * 8u, *bitrate); | |
| 225 | |
| 226 // Now that first sample should drop out... | |
| 227 now_ms += 1; | |
| 228 bitrate = stats_.Rate(now_ms); | |
| 229 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 230 EXPECT_EQ(1000 * 8u, *bitrate); | |
| 231 } | |
| 232 | |
| 233 TEST_F(RateStatisticsTest, HandlesZeroCounts) { | |
| 234 int64_t now_ms = 0; | |
| 235 stats_.Reset(); | |
| 236 // Expecting 0 after init. | |
| 237 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 238 | |
| 239 stats_.Update(kWindowMs, now_ms); | |
| 240 now_ms += kWindowMs - 1; | |
| 241 stats_.Update(0, now_ms); | |
| 242 rtc::Optional<uint32_t> bitrate = stats_.Rate(now_ms); | |
| 243 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 244 EXPECT_EQ(1000 * 8u, *bitrate); | |
| 245 | |
| 246 // Move window along so first data point falls out. | |
| 247 ++now_ms; | |
| 248 bitrate = stats_.Rate(now_ms); | |
| 249 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 250 EXPECT_EQ(0u, *bitrate); | |
| 251 | |
| 252 // Move window so last data point falls out. | |
| 253 now_ms += kWindowMs; | |
| 254 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 255 } | |
| 256 | |
| 257 TEST_F(RateStatisticsTest, HandlesQuietPeriods) { | |
| 258 int64_t now_ms = 0; | |
| 259 stats_.Reset(); | |
| 260 // Expecting 0 after init. | |
| 261 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 262 | |
| 263 stats_.Update(0, now_ms); | |
| 264 now_ms += kWindowMs - 1; | |
| 265 rtc::Optional<uint32_t> bitrate = stats_.Rate(now_ms); | |
| 266 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 267 EXPECT_EQ(0u, *bitrate); | |
| 268 | |
| 269 // Move window along so first data point falls out. | |
| 270 ++now_ms; | |
| 271 EXPECT_FALSE(static_cast<bool>(stats_.Rate(now_ms))); | |
| 272 | |
| 273 // Move window a long way out. | |
| 274 now_ms += 2 * kWindowMs; | |
| 275 stats_.Update(0, now_ms); | |
| 276 bitrate = stats_.Rate(now_ms); | |
| 277 EXPECT_TRUE(static_cast<bool>(bitrate)); | |
| 278 EXPECT_EQ(0u, *bitrate); | |
| 279 } | |
| 280 } // namespace | |
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