Move usage of QualityScaler to ViEEncoder.

webrtc/modules/video_coding/utility/quality_scaler.h

Index: webrtc/modules/video_coding/utility/quality_scaler.h
diff --git a/webrtc/modules/video_coding/utility/quality_scaler.h b/webrtc/modules/video_coding/utility/quality_scaler.h
index c0f94409ce30ee0d5b46260857bc42f696f72c01..5734e6647e653dd4c99a74145b047e1d48aa4e1e 100644
--- a/webrtc/modules/video_coding/utility/quality_scaler.h
+++ b/webrtc/modules/video_coding/utility/quality_scaler.h
@@ -11,61 +11,73 @@
 #ifndef WEBRTC_MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_
 #define WEBRTC_MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_
 
+#include <utility>
+
 #include "webrtc/common_types.h"
-#include "webrtc/common_video/include/i420_buffer_pool.h"
+#include "webrtc/video_encoder.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/base/sequenced_task_checker.h"
 #include "webrtc/modules/video_coding/utility/moving_average.h"
 
 namespace webrtc {
-class QualityScaler {
+
+// An interface for a class that receives scale up/down requests.
+class ScalingObserverInterface {
  public:
-  struct Resolution {
-    int width;
-    int height;
-  };
+  enum ScaleReason : size_t { kQuality = 0, kCpu = 1 };
+  static const size_t kScaleReasonSize = 2;
+  // Called to signal that we can handle larger frames.
+  virtual void ScaleUp(ScaleReason reason) = 0;
+  // Called to signal that encoder to scale down.
+  virtual void ScaleDown(ScaleReason reason) = 0;
 
-  QualityScaler();
-  void Init(VideoCodecType codec_type,
-            int initial_bitrate_kbps,
-            int width,
-            int height,
-            int fps);
-  void Init(int low_qp_threshold,
-            int high_qp_threshold,
-            int initial_bitrate_kbps,
-            int width,
-            int height,
-            int fps);
-  void ReportFramerate(int framerate);
-  void ReportQP(int qp);
+ protected:
+  virtual ~ScalingObserverInterface() {}
+};
+
+// QualityScaler runs asynchronously and monitors QP values of encoded frames.
+// It holds a reference to a ScalingObserverInterface implementation to signal
+// an intent to scale up or down.
+class QualityScaler {
+ public:
+  // Construct a QualityScaler with a given |observer|.
+  // This starts the quality scaler periodically checking what the average QP
+  // has been recently.
+  QualityScaler(ScalingObserverInterface* observer, VideoCodecType codec_type);
+  // If specific thresholds are desired these can be supplied as |thresholds|.
+  QualityScaler(ScalingObserverInterface* observer,
+                VideoEncoder::QpThresholds thresholds);
+  virtual ~QualityScaler();
+  // Should be called each time the encoder drops a frame
   void ReportDroppedFrame();
-  void OnEncodeFrame(int width, int height);
-  Resolution GetScaledResolution() const;
-  rtc::scoped_refptr<VideoFrameBuffer> GetScaledBuffer(
-      const rtc::scoped_refptr<VideoFrameBuffer>& frame);
-  int downscale_shift() const { return downscale_shift_; }
+  // Inform the QualityScaler of the last seen QP.
+  void ReportQP(int qp);
+
+  // The following members declared protected for testing purposes
+ protected:
+  QualityScaler(ScalingObserverInterface* observer,
+                VideoEncoder::QpThresholds thresholds,
+                int64_t sampling_period);
 
  private:
+  class CheckQPTask;
+  void CheckQP();
   void ClearSamples();
-  void ScaleUp();
-  void ScaleDown();
-  void UpdateTargetResolution(int width, int height);
-
-  I420BufferPool pool_;
+  void ReportQPLow();
+  void ReportQPHigh();
+  int64_t GetSamplingPeriodMs() const;
 
-  size_t num_samples_downscale_;
-  size_t num_samples_upscale_;
-  bool fast_rampup_;
-  MovingAverage average_qp_;
-  MovingAverage framedrop_percent_;
+  CheckQPTask* check_qp_task_ GUARDED_BY(&task_checker_);
+  ScalingObserverInterface* const observer_ GUARDED_BY(&task_checker_);
+  rtc::SequencedTaskChecker task_checker_;
 
-  int low_qp_threshold_;
-  int high_qp_threshold_;
-  Resolution target_res_;
+  const int64_t sampling_period_ms_;
+  bool fast_rampup_ GUARDED_BY(&task_checker_);
+  MovingAverage average_qp_ GUARDED_BY(&task_checker_);
+  MovingAverage framedrop_percent_ GUARDED_BY(&task_checker_);
 
-  int downscale_shift_;
-  int maximum_shift_;
+  VideoEncoder::QpThresholds thresholds_ GUARDED_BY(&task_checker_);
 };
-
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_UTILITY_QUALITY_SCALER_H_