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/*
* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "common_video/frame_rate_estimator.h"
#include "system_wrappers/include/clock.h"
#include "test/gmock.h"
#include "test/gtest.h"
namespace webrtc {
namespace {
constexpr TimeDelta kDefaultWindow = TimeDelta::Millis(1000);
}
class FrameRateEstimatorTest : public ::testing::Test {
public:
FrameRateEstimatorTest() : clock_(123), estimator_(kDefaultWindow) {}
protected:
SimulatedClock clock_;
FrameRateEstimator estimator_;
};
TEST_F(FrameRateEstimatorTest, NoEstimateWithLessThanTwoFrames) {
EXPECT_FALSE(estimator_.GetAverageFps());
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_FALSE(estimator_.GetAverageFps());
clock_.AdvanceTime(TimeDelta::Millis(33));
EXPECT_FALSE(estimator_.GetAverageFps());
}
TEST_F(FrameRateEstimatorTest, NoEstimateWithZeroSpan) {
// Two frames, but they are spanning 0ms so can't estimate frame rate.
estimator_.OnFrame(clock_.CurrentTime());
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_FALSE(estimator_.GetAverageFps());
}
TEST_F(FrameRateEstimatorTest, SingleSpanFps) {
const double kExpectedFps = 30.0;
estimator_.OnFrame(clock_.CurrentTime());
clock_.AdvanceTime(TimeDelta::Seconds(1) / kExpectedFps);
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
}
TEST_F(FrameRateEstimatorTest, AverageFps) {
// Insert frames a intervals corresponding to 10fps for half the window, then
// 40fps half the window. The average should be 20fps.
const double kLowFps = 10.0;
const double kHighFps = 30.0;
const double kExpectedFps = 20.0;
const Timestamp start_time = clock_.CurrentTime();
while (clock_.CurrentTime() - start_time < kDefaultWindow / 2) {
estimator_.OnFrame(clock_.CurrentTime());
clock_.AdvanceTime(TimeDelta::Seconds(1) / kLowFps);
}
while (clock_.CurrentTime() - start_time < kDefaultWindow) {
estimator_.OnFrame(clock_.CurrentTime());
clock_.AdvanceTime(TimeDelta::Seconds(1) / kHighFps);
}
EXPECT_NEAR(*estimator_.GetAverageFps(), kExpectedFps, 0.001);
}
TEST_F(FrameRateEstimatorTest, CullsOldFramesFromAveragingWindow) {
// Two frames, just on the border of the 1s window => 1 fps.
estimator_.OnFrame(clock_.CurrentTime());
clock_.AdvanceTime(kDefaultWindow);
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_TRUE(estimator_.GetAverageFps());
EXPECT_NEAR(*estimator_.GetAverageFps(), 1.0, 0.001);
// Oldest frame should just be pushed out the window, leaving a single frame
// => no estimate possible.
clock_.AdvanceTime(TimeDelta::Micros(1));
EXPECT_FALSE(estimator_.GetAverageFps(clock_.CurrentTime()));
}
TEST_F(FrameRateEstimatorTest, Reset) {
estimator_.OnFrame(clock_.CurrentTime());
clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_TRUE(estimator_.GetAverageFps());
// Clear estimator, no estimate should be possible even after inserting one
// new frame.
estimator_.Reset();
EXPECT_FALSE(estimator_.GetAverageFps());
clock_.AdvanceTime(TimeDelta::Seconds(1) / 30);
estimator_.OnFrame(clock_.CurrentTime());
EXPECT_FALSE(estimator_.GetAverageFps());
}
} // namespace webrtc