Adapt encoder behavior to target bitrate

remoting/codec/webrtc_video_encoder_vpx.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2016 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 REMOTING_CODEC_VIDEO_ENCODER_VPX_H_
-#define REMOTING_CODEC_VIDEO_ENCODER_VPX_H_
+#ifndef REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_VPX_H_
+#define REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_VPX_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/time/default_tick_clock.h"
 #include "base/time/time.h"
 #include "remoting/codec/scoped_vpx_codec.h"
 #include "remoting/codec/video_encoder.h"
 #include "remoting/codec/video_encoder_helper.h"
+#include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
 
 typedef struct vpx_image vpx_image_t;
 
 namespace webrtc {
 class DesktopRegion;
 class DesktopSize;
 }  // namespace webrtc
 
 namespace remoting {
 
-class VideoEncoderVpx : public VideoEncoder {
+// This is a copy of VideoEncoderVpx with enhancements to encoder for use
+// over WebRTC as transport. The original VideoEncoderVpx should be deleted
+// once the old implementation is no longer in use.
+class WebRtcVideoEncoderVpx : public VideoEncoder {
  public:
   // Create encoder for the specified protocol.
-  static std::unique_ptr<VideoEncoderVpx> CreateForVP8();
-  static std::unique_ptr<VideoEncoderVpx> CreateForVP9();
+  static std::unique_ptr<WebRtcVideoEncoderVpx> CreateForVP8();
+  static std::unique_ptr<WebRtcVideoEncoderVpx> CreateForVP9();
 
-  ~VideoEncoderVpx() override;
+  ~WebRtcVideoEncoderVpx() override;
 
   void SetTickClockForTests(base::TickClock* tick_clock);
 
   // VideoEncoder interface.
   void SetLosslessEncode(bool want_lossless) override;
   void SetLosslessColor(bool want_lossless) override;
   std::unique_ptr<VideoPacket> Encode(const webrtc::DesktopFrame& frame,
                                       uint32_t flags) override;
+  void UpdateTargetBitrate(uint32_t bitrate) override;
 
  private:
-  explicit VideoEncoderVpx(bool use_vp9);
+  explicit WebRtcVideoEncoderVpx(bool use_vp9);
 
   // (Re)Configures this instance to encode frames of the specified |size|,
   // with the configured lossless color & encoding modes.
   void Configure(const webrtc::DesktopSize& size);
 
   // Prepares |image_| for encoding. Writes updated rectangles into
   // |updated_region|.
   void PrepareImage(const webrtc::DesktopFrame& frame,
                     webrtc::DesktopRegion* updated_region);
 
   // Updates the active map according to |updated_region|. Active map is then
   // given to the encoder to speed up encoding.
   void SetActiveMapFromRegion(const webrtc::DesktopRegion& updated_region);
 
   // Adds areas changed in the most recent frame to |updated_region|. This
   // includes both content changes and areas enhanced by cyclic refresh.
   void UpdateRegionFromActiveMap(webrtc::DesktopRegion* updated_region);
 
   // True if the encoder is for VP9, false for VP8.
   const bool use_vp9_;
 
   // Options controlling VP9 encode quantization and color space.
   // These are always off (false) for VP8.
   bool lossless_encode_ = false;
   bool lossless_color_ = false;
 
   // Holds the initialized & configured codec.
   ScopedVpxCodec codec_;
 
+  vpx_codec_enc_cfg_t config_;
+  uint32_t target_bitrate_kbps_;
+
   // Used to generate zero-based frame timestamps.
   base::TimeTicks timestamp_base_;
 
   // VPX image and buffer to hold the actual YUV planes.
   std::unique_ptr<vpx_image_t> image_;
   std::unique_ptr<uint8_t[]> image_buffer_;
 
   // Active map used to optimize out processing of un-changed macroblocks.
   std::unique_ptr<uint8_t[]> active_map_;
   webrtc::DesktopSize active_map_size_;
 
   // True if the codec wants unchanged frames to finish topping-off with.
   bool encode_unchanged_frame_;
 
   // Used to help initialize VideoPackets from DesktopFrames.
   VideoEncoderHelper helper_;
 
   base::DefaultTickClock default_tick_clock_;
   base::TickClock* clock_;
 
-  DISALLOW_COPY_AND_ASSIGN(VideoEncoderVpx);
+  DISALLOW_COPY_AND_ASSIGN(WebRtcVideoEncoderVpx);
 };
 
 }  // namespace remoting
 
-#endif  // REMOTING_CODEC_VIDEO_ENCODER_VPX_H_
+#endif  // REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_VPX_H_