1 /* 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_ 12 #define MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_ 13 14 #include <utility> 15 16 #include "api/optional.h" 17 #include "api/video_codecs/video_encoder.h" 18 #include "common_types.h" // NOLINT(build/include) 19 #include "modules/video_coding/utility/moving_average.h" 20 #include "rtc_base/sequenced_task_checker.h" 21 22 namespace webrtc { 23 24 // An interface for signaling requests to limit or increase the resolution or 25 // framerate of the captured video stream. 26 class AdaptationObserverInterface { 27 public: 28 // Indicates if the adaptation is due to overuse of the CPU resources, or if 29 // the quality of the encoded frames have dropped too low. 30 enum AdaptReason : size_t { kQuality = 0, kCpu = 1 }; 31 static const size_t kScaleReasonSize = 2; 32 // Called to signal that we can handle larger or more frequent frames. 33 virtual void AdaptUp(AdaptReason reason) = 0; 34 // Called to signal that the source should reduce the resolution or framerate. 35 virtual void AdaptDown(AdaptReason reason) = 0; 36 37 protected: ~AdaptationObserverInterface()38 virtual ~AdaptationObserverInterface() {} 39 }; 40 41 // QualityScaler runs asynchronously and monitors QP values of encoded frames. 42 // It holds a reference to an AdaptationObserverInterface implementation to 43 // signal an intent to scale up or down. 44 class QualityScaler { 45 public: 46 // Construct a QualityScaler with a given |observer|. 47 // This starts the quality scaler periodically checking what the average QP 48 // has been recently. 49 QualityScaler(AdaptationObserverInterface* observer, 50 VideoCodecType codec_type); 51 // If specific thresholds are desired these can be supplied as |thresholds|. 52 QualityScaler(AdaptationObserverInterface* observer, 53 VideoEncoder::QpThresholds thresholds); 54 virtual ~QualityScaler(); 55 // Should be called each time the encoder drops a frame 56 void ReportDroppedFrame(); 57 // Inform the QualityScaler of the last seen QP. 58 void ReportQP(int qp); 59 60 // The following members declared protected for testing purposes 61 protected: 62 QualityScaler(AdaptationObserverInterface* observer, 63 VideoEncoder::QpThresholds thresholds, 64 int64_t sampling_period); 65 66 private: 67 class CheckQPTask; 68 void CheckQP(); 69 void ClearSamples(); 70 void ReportQPLow(); 71 void ReportQPHigh(); 72 int64_t GetSamplingPeriodMs() const; 73 74 CheckQPTask* check_qp_task_ RTC_GUARDED_BY(&task_checker_); 75 AdaptationObserverInterface* const observer_ RTC_GUARDED_BY(&task_checker_); 76 rtc::SequencedTaskChecker task_checker_; 77 78 const int64_t sampling_period_ms_; 79 bool fast_rampup_ RTC_GUARDED_BY(&task_checker_); 80 MovingAverage average_qp_ RTC_GUARDED_BY(&task_checker_); 81 MovingAverage framedrop_percent_ RTC_GUARDED_BY(&task_checker_); 82 83 VideoEncoder::QpThresholds thresholds_ RTC_GUARDED_BY(&task_checker_); 84 }; 85 } // namespace webrtc 86 87 #endif // MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_ 88