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The Tor Browser
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frame_rate_estimator_unittest.cc (3646B)

      1 /*
      2 *  Copyright (c) 2019 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 "common_video/frame_rate_estimator.h"
     12 
     13 #include "api/units/time_delta.h"
     14 #include "api/units/timestamp.h"
     15 #include "system_wrappers/include/clock.h"
     16 #include "test/gtest.h"
     17 
     18 namespace webrtc {
     19 namespace {
     20 constexpr TimeDelta kDefaultWindow = TimeDelta::Millis(1000);
     21 }  // namespace
     22 
     23 class FrameRateEstimatorTest : public ::testing::Test {
     24 public:
     25  FrameRateEstimatorTest() : clock_(123), estimator_(kDefaultWindow) {}
     26 
     27 protected:
     28  SimulatedClock clock_;
     29  FrameRateEstimator estimator_;
     30 };
     31 
     32 TEST_F(FrameRateEstimatorTest, NoEstimateWithLessThanTwoFrames) {
     33  EXPECT_FALSE(estimator_.GetAverageFps());
     34  estimator_.OnFrame(clock_.CurrentTime());
     35  EXPECT_FALSE(estimator_.GetAverageFps());
     36  clock_.AdvanceTime(TimeDelta::Millis(33));
     37  EXPECT_FALSE(estimator_.GetAverageFps());
     38 }
     39 
     40 TEST_F(FrameRateEstimatorTest, NoEstimateWithZeroSpan) {
     41  // Two frames, but they are spanning 0ms so can't estimate frame rate.
     42  estimator_.OnFrame(clock_.CurrentTime());
     43  estimator_.OnFrame(clock_.CurrentTime());
     44  EXPECT_FALSE(estimator_.GetAverageFps());
     45 }
     46 
     47 TEST_F(FrameRateEstimatorTest, SingleSpanFps) {
     48  const double kExpectedFps = 30.0;
     49  estimator_.OnFrame(clock_.CurrentTime());
     50  clock_.AdvanceTime(TimeDelta::Seconds(1) / kExpectedFps);
     51  estimator_.OnFrame(clock_.CurrentTime());
     52  EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
     53 }
     54 
     55 TEST_F(FrameRateEstimatorTest, AverageFps) {
     56  // Insert frames a intervals corresponding to 10fps for half the window, then
     57  // 40fps half the window. The average should be 20fps.
     58  const double kLowFps = 10.0;
     59  const double kHighFps = 30.0;
     60  const double kExpectedFps = 20.0;
     61 
     62  const Timestamp start_time = clock_.CurrentTime();
     63  while (clock_.CurrentTime() - start_time < kDefaultWindow / 2) {
     64    estimator_.OnFrame(clock_.CurrentTime());
     65    clock_.AdvanceTime(TimeDelta::Seconds(1) / kLowFps);
     66  }
     67  while (clock_.CurrentTime() - start_time < kDefaultWindow) {
     68    estimator_.OnFrame(clock_.CurrentTime());
     69    clock_.AdvanceTime(TimeDelta::Seconds(1) / kHighFps);
     70  }
     71 
     72  EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
     73 }
     74 
     75 TEST_F(FrameRateEstimatorTest, CullsOldFramesFromAveragingWindow) {
     76  // Two frames, just on the border of the 1s window => 1 fps.
     77  estimator_.OnFrame(clock_.CurrentTime());
     78  clock_.AdvanceTime(kDefaultWindow);
     79  estimator_.OnFrame(clock_.CurrentTime());
     80  EXPECT_TRUE(estimator_.GetAverageFps());
     81  EXPECT_NEAR(*estimator_.GetAverageFps(), 1.0, 0.001);
     82 
     83  // Oldest frame should just be pushed out the window, leaving a single frame
     84  // => no estimate possible.
     85  clock_.AdvanceTime(TimeDelta::Micros(1));
     86  EXPECT_FALSE(estimator_.GetAverageFps(clock_.CurrentTime()));
     87 }
     88 
     89 TEST_F(FrameRateEstimatorTest, Reset) {
     90  estimator_.OnFrame(clock_.CurrentTime());
     91  clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
     92  estimator_.OnFrame(clock_.CurrentTime());
     93  EXPECT_TRUE(estimator_.GetAverageFps());
     94 
     95  // Clear estimator, no estimate should be possible even after inserting one
     96  // new frame.
     97  estimator_.Reset();
     98  EXPECT_FALSE(estimator_.GetAverageFps());
     99  clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
    100  estimator_.OnFrame(clock_.CurrentTime());
    101  EXPECT_FALSE(estimator_.GetAverageFps());
    102 }
    103 
    104 }  // namespace webrtc