In screenshare mode, suppress VP8 bitrate overshoot and increase quality

webrtc/modules/video_coding/codecs/vp8/screenshare_layers.h

 /* Copyright (c) 2013 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 WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_SCREENSHARE_LAYERS_H_
 #define WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_SCREENSHARE_LAYERS_H_
 
 #include <list>
 
 #include "vpx/vpx_encoder.h"
 
 #include "webrtc/modules/video_coding/codecs/vp8/temporal_layers.h"
 #include "webrtc/modules/video_coding/utility/include/frame_dropper.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 struct CodecSpecificInfoVP8;
 
 class ScreenshareLayers : public TemporalLayers {
  public:
   static const double kMaxTL0FpsReduction;
   static const double kAcceptableTargetOvershoot;
 
-  ScreenshareLayers(int num_temporal_layers,
-                    uint8_t initial_tl0_pic_idx,
-                    FrameDropper* tl0_frame_dropper,
-                    FrameDropper* tl1_frame_dropper);
+  ScreenshareLayers(int num_temporal_layers, uint8_t initial_tl0_pic_idx);
   virtual ~ScreenshareLayers() {}
 
   // Returns the recommended VP8 encode flags needed. May refresh the decoder
   // and/or update the reference buffers.
-  virtual int EncodeFlags(uint32_t timestamp);
+  int EncodeFlags(uint32_t timestamp) override;
 
-  virtual bool ConfigureBitrates(int bitrate_kbit,
-                                 int max_bitrate_kbit,
-                                 int framerate,
-                                 vpx_codec_enc_cfg_t* cfg);
+  bool ConfigureBitrates(int bitrate_kbit,
+                         int max_bitrate_kbit,
+                         int framerate,
+                         vpx_codec_enc_cfg_t* cfg) override;
 
-  virtual void PopulateCodecSpecific(bool base_layer_sync,
-                                     CodecSpecificInfoVP8 *vp8_info,
-                                     uint32_t timestamp);
+  void PopulateCodecSpecific(bool base_layer_sync,
+                             CodecSpecificInfoVP8* vp8_info,
+                             uint32_t timestamp) override;
 
-  virtual void FrameEncoded(unsigned int size, uint32_t timestamp);
+  void FrameEncoded(unsigned int size, uint32_t timestamp, int qp) override;
 
-  virtual int CurrentLayerId() const;
+  int CurrentLayerId() const override;
+
+  bool UpdateConfiguration(vpx_codec_enc_cfg_t* cfg) override;
 
  private:
-  void CalculateFramerate(uint32_t timestamp);
   bool TimeToSync(uint32_t timestamp) const;
 
-  FrameDropper* tl0_frame_dropper_;
-  FrameDropper* tl1_frame_dropper_;
   int number_of_temporal_layers_;
   bool last_base_layer_sync_;
   uint8_t tl0_pic_idx_;
   int active_layer_;
-  std::list<uint32_t> timestamp_list_;
-  int framerate_;
-  int64_t last_sync_timestamp_;
+  uint32_t last_timestamp_;
+  uint32_t last_sync_timestamp_;
+  int min_qp_;
+  int max_qp_;
+  uint32_t max_debt_bytes_;
+
+  struct TemporalLayer {
+    TemporalLayer()
+        : state(State::kNormal),
+          enhanced_max_qp(-1),
+          last_qp(-1),
+          debt_bytes_(0),
+          target_rate_kbps_(0) {}
+
+    enum class State {
+      kNormal,
+      kDropped,
+      kReencoded,
+      kQualityBoost,
+    } state;
+
+    int enhanced_max_qp;
+    int last_qp;
+    uint32_t debt_bytes_;
+    uint32_t target_rate_kbps_;
+
+    void UpdateDebt(int64_t delta_ms);
+  } layers_[2];
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_SCREENSHARE_LAYERS_H_