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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_FRAME_RATE_ESTIMATOR_H_
#define MEDIA_BASE_FRAME_RATE_ESTIMATOR_H_
#include "base/macros.h"
#include "media/base/media_export.h"
#include "media/base/moving_average.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
namespace media {
// Utility class to provide a bucketed frame rate estimator. This class should
// provide a stable frame rate, as measured by a sequence of frame durations,
// or an indication that the fps isn't currently stable.
class MEDIA_EXPORT FrameRateEstimator {
public:
FrameRateEstimator();
~FrameRateEstimator();
// Add a frame with the given duration.
void AddSample(base::TimeDelta frame_duration);
// Return the current (bucketed) frame rate (not duration), or nullopt if one
// isn't available with suitable certainty.
absl::optional<int> ComputeFPS();
// Reset everything.
void Reset();
// Return the current number of required samples.
int GetRequiredSamplesForTesting() const;
// Return the min / max samples that we'll require for fast / slow estimates.
int GetMinSamplesForTesting() const;
int GetMaxSamplesForTesting() const;
private:
MovingAverage duration_;
uint64_t required_samples_;
// Most recently computed bucketed FPS (not duration), if any.
absl::optional<int> most_recent_bucket_;
};
} // namespace media
#endif // MEDIA_BASE_FRAME_RATE_ESTIMATOR_H_