blob: 47ed58e13724ab6cebbd56bb8479387bf289805a [file] [log] [blame]
// Copyright (c) 2015 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.
#include "base/macros.h"
#include "base/time/time.h"
#include "media/capture/capture_export.h"
namespace media {
// Filters a sequence of events to achieve a target frequency.
class CAPTURE_EXPORT SmoothEventSampler {
explicit SmoothEventSampler(base::TimeDelta min_capture_period);
// Get/Set minimum capture period. When setting a new value, the state of the
// sampler is retained so that sampling will continue smoothly.
base::TimeDelta min_capture_period() const { return min_capture_period_; }
void SetMinCapturePeriod(base::TimeDelta p);
// Add a new event to the event history, and consider whether it ought to be
// sampled. The event is not recorded as a sample until RecordSample() is
// called.
void ConsiderPresentationEvent(base::TimeTicks event_time);
// Returns true if the last event considered should be sampled.
bool ShouldSample() const;
// Operates on the last event added by ConsiderPresentationEvent(), marking
// it as sampled. After this point we are current in the stream of events, as
// we have sampled the most recent event.
void RecordSample();
// Returns true if ConsiderPresentationEvent() has been called since the last
// call to RecordSample().
bool HasUnrecordedEvent() const;
base::TimeDelta min_capture_period_;
base::TimeDelta token_bucket_capacity_;
base::TimeTicks current_event_;
base::TimeTicks last_sample_;
base::TimeDelta token_bucket_;
} // namespace media