fb8fc5391e
This is done by changing the RateStatistics so that it resets its window when the accumulator is empty. It also keeps a dynamic window, so that the rates computed before a full window worth of data has been received will be computed over a smaller window. This means that the rate will be closer to the true rate, but with a higher variance. BUG=webrtc:5773 R=perkj@webrtc.org, sprang@webrtc.org Review URL: https://codereview.webrtc.org/1908893003 . Cr-Commit-Position: refs/heads/master@{#12470}
133 lines
4.1 KiB
C++
133 lines
4.1 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include <algorithm>
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#include "testing/gtest/include/gtest/gtest.h"
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#include "webrtc/base/rate_statistics.h"
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namespace {
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using webrtc::RateStatistics;
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const int64_t kWindowMs = 500;
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class RateStatisticsTest : public ::testing::Test {
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protected:
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RateStatisticsTest() : stats_(kWindowMs, 8000) {}
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RateStatistics stats_;
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};
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TEST_F(RateStatisticsTest, TestStrictMode) {
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int64_t now_ms = 0;
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// Should be initialized to 0.
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EXPECT_EQ(0u, stats_.Rate(now_ms));
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stats_.Update(1500, now_ms);
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// Expecting 1200 kbps since the window is initially kept small and grows as
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// we have more data.
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EXPECT_EQ(12000000u, stats_.Rate(now_ms));
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stats_.Reset();
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// Expecting 0 after init.
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EXPECT_EQ(0u, stats_.Rate(now_ms));
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for (int i = 0; i < 100000; ++i) {
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if (now_ms % 10 == 0) {
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stats_.Update(1500, now_ms);
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}
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// Approximately 1200 kbps expected. Not exact since when packets
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// are removed we will jump 10 ms to the next packet.
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if (now_ms > 0 && now_ms % kWindowMs == 0) {
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EXPECT_NEAR(1200000u, stats_.Rate(now_ms), 22000u);
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}
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now_ms += 1;
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}
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now_ms += kWindowMs;
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// The window is 2 seconds. If nothing has been received for that time
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// the estimate should be 0.
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EXPECT_EQ(0u, stats_.Rate(now_ms));
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}
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TEST_F(RateStatisticsTest, IncreasingThenDecreasingBitrate) {
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int64_t now_ms = 0;
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stats_.Reset();
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// Expecting 0 after init.
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uint32_t bitrate = stats_.Rate(now_ms);
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EXPECT_EQ(0u, bitrate);
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const uint32_t kExpectedBitrate = 8000000;
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// 1000 bytes per millisecond until plateau is reached.
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int prev_error = kExpectedBitrate;
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while (++now_ms < 10000) {
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stats_.Update(1000, now_ms);
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bitrate = stats_.Rate(now_ms);
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int error = kExpectedBitrate - bitrate;
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error = std::abs(error);
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// Expect the estimation error to decrease as the window is extended.
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EXPECT_LE(error, prev_error + 1);
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prev_error = error;
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}
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// Window filled, expect to be close to 8000000.
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EXPECT_EQ(kExpectedBitrate, bitrate);
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// 1000 bytes per millisecond until 10-second mark, 8000 kbps expected.
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while (++now_ms < 10000) {
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stats_.Update(1000, now_ms);
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bitrate = stats_.Rate(now_ms);
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EXPECT_EQ(kExpectedBitrate, bitrate);
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}
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// Zero bytes per millisecond until 0 is reached.
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while (++now_ms < 20000) {
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stats_.Update(0, now_ms);
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uint32_t new_bitrate = stats_.Rate(now_ms);
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if (new_bitrate != bitrate) {
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// New bitrate must be lower than previous one.
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EXPECT_LT(new_bitrate, bitrate);
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} else {
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// 0 kbps expected.
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EXPECT_EQ(0u, bitrate);
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break;
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}
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bitrate = new_bitrate;
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}
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// Zero bytes per millisecond until 20-second mark, 0 kbps expected.
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while (++now_ms < 20000) {
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stats_.Update(0, now_ms);
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EXPECT_EQ(0u, stats_.Rate(now_ms));
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}
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}
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TEST_F(RateStatisticsTest, ResetAfterSilence) {
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int64_t now_ms = 0;
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stats_.Reset();
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// Expecting 0 after init.
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uint32_t bitrate = stats_.Rate(now_ms);
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EXPECT_EQ(0u, bitrate);
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const uint32_t kExpectedBitrate = 8000000;
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// 1000 bytes per millisecond until the window has been filled.
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int prev_error = kExpectedBitrate;
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while (++now_ms < 10000) {
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stats_.Update(1000, now_ms);
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bitrate = stats_.Rate(now_ms);
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int error = kExpectedBitrate - bitrate;
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error = std::abs(error);
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// Expect the estimation error to decrease as the window is extended.
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EXPECT_LE(error, prev_error + 1);
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prev_error = error;
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}
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// Window filled, expect to be close to 8000000.
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EXPECT_EQ(kExpectedBitrate, bitrate);
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now_ms += kWindowMs + 1;
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EXPECT_EQ(0u, stats_.Rate(now_ms));
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stats_.Update(1000, now_ms);
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// We expect one sample of 1000 bytes, and that the bitrate is measured over
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// 1 ms, i.e., 8 * 1000 / 0.001 = 8000000.
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EXPECT_EQ(kExpectedBitrate, stats_.Rate(now_ms));
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}
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} // namespace
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