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/*
* Copyright (c) 2014 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.
*/
#ifndef MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_
#define MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "absl/types/optional.h"
#include "api/video_codecs/video_encoder.h"
#include "rtc_base/experiments/quality_scaling_experiment.h"
#include "rtc_base/numerics/moving_average.h"
#include "rtc_base/synchronization/sequence_checker.h"
#include "rtc_base/task_queue.h"
#include "rtc_base/task_utils/repeating_task.h"
namespace webrtc {
// An interface for signaling requests to limit or increase the resolution or
// framerate of the captured video stream.
class AdaptationObserverInterface {
public:
// Indicates if the adaptation is due to overuse of the CPU resources, or if
// the quality of the encoded frames have dropped too low.
enum AdaptReason : size_t { kQuality = 0, kCpu = 1 };
static const size_t kScaleReasonSize = 2;
// Called to signal that we can handle larger or more frequent frames.
virtual void AdaptUp(AdaptReason reason) = 0;
// Called to signal that the source should reduce the resolution or framerate.
// Returns false if a downgrade was requested but the request did not result
// in a new limiting resolution or fps.
virtual bool AdaptDown(AdaptReason reason) = 0;
protected:
virtual ~AdaptationObserverInterface() {}
};
// QualityScaler runs asynchronously and monitors QP values of encoded frames.
// It holds a reference to an AdaptationObserverInterface implementation to
// signal an intent to scale up or down.
class QualityScaler {
public:
// Construct a QualityScaler with given |thresholds| and |observer|.
// This starts the quality scaler periodically checking what the average QP
// has been recently.
QualityScaler(rtc::TaskQueue* task_queue,
AdaptationObserverInterface* observer,
VideoEncoder::QpThresholds thresholds);
virtual ~QualityScaler();
// Should be called each time a frame is dropped at encoding.
void ReportDroppedFrameByMediaOpt();
void ReportDroppedFrameByEncoder();
// Inform the QualityScaler of the last seen QP.
void ReportQp(int qp, int64_t time_sent_us);
void SetQpThresholds(VideoEncoder::QpThresholds thresholds);
bool QpFastFilterLow() const;
// The following members declared protected for testing purposes.
protected:
QualityScaler(rtc::TaskQueue* task_queue,
AdaptationObserverInterface* observer,
VideoEncoder::QpThresholds thresholds,
int64_t sampling_period_ms);
private:
class QpSmoother;
void CheckQp();
void ClearSamples();
void ReportQpLow();
void ReportQpHigh();
int64_t GetSamplingPeriodMs() const;
RepeatingTaskHandle check_qp_task_ RTC_GUARDED_BY(&task_checker_);
AdaptationObserverInterface* const observer_ RTC_GUARDED_BY(&task_checker_);
SequenceChecker task_checker_;
VideoEncoder::QpThresholds thresholds_ RTC_GUARDED_BY(&task_checker_);
const int64_t sampling_period_ms_;
bool fast_rampup_ RTC_GUARDED_BY(&task_checker_);
rtc::MovingAverage average_qp_ RTC_GUARDED_BY(&task_checker_);
rtc::MovingAverage framedrop_percent_media_opt_
RTC_GUARDED_BY(&task_checker_);
rtc::MovingAverage framedrop_percent_all_ RTC_GUARDED_BY(&task_checker_);
// Used by QualityScalingExperiment.
const bool experiment_enabled_;
QualityScalingExperiment::Config config_ RTC_GUARDED_BY(&task_checker_);
std::unique_ptr<QpSmoother> qp_smoother_high_ RTC_GUARDED_BY(&task_checker_);
std::unique_ptr<QpSmoother> qp_smoother_low_ RTC_GUARDED_BY(&task_checker_);
bool observed_enough_frames_ RTC_GUARDED_BY(&task_checker_);
const size_t min_frames_needed_;
const double initial_scale_factor_;
const absl::optional<double> scale_factor_;
bool adapt_called_ RTC_GUARDED_BY(&task_checker_);
bool adapt_failed_ RTC_GUARDED_BY(&task_checker_);
};
} // namespace webrtc
#endif // MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_