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- // 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.
- #ifndef MEDIA_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_H_
- #define MEDIA_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_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 {
- public:
- explicit SmoothEventSampler(base::TimeDelta min_capture_period);
- SmoothEventSampler(const SmoothEventSampler&) = delete;
- SmoothEventSampler& operator=(const SmoothEventSampler&) = delete;
- // 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;
- private:
- base::TimeDelta min_capture_period_;
- base::TimeDelta token_bucket_capacity_;
- base::TimeTicks current_event_;
- base::TimeTicks last_sample_;
- base::TimeDelta token_bucket_;
- };
- } // namespace media
- #endif // MEDIA_CAPTURE_CONTENT_SMOOTH_EVENT_SAMPLER_H_
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