Interface with webrtc through encoded frames

remoting/protocol/webrtc_video_encoder.h

+// 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_PROTOCOL_WEBRTC_VIDEO_ENCODER_H_
+#define REMOTING_PROTOCOL_WEBRTC_VIDEO_ENCODER_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/synchronization/lock.h"
+#include "remoting/proto/video.pb.h"
+#include "third_party/webrtc/media/engine/webrtcvideoencoderfactory.h"
+#include "third_party/webrtc/modules/video_coding/include/video_codec_interface.h"
+
+namespace remoting {
+
+// This is the interface between the WebRtc engine and the external encoder
+// provided by remoting. WebRtc provides feedback on network bandwidth, latency
+// & RTT and in turn remoting passes encoded frames as they get encoded
+// through the capture pipeline.
+class WebRtcVideoEncoder : public webrtc::VideoEncoder {
+ public:
+  enum State { kUninitialized = 0, kInitialized };
+  explicit WebRtcVideoEncoder(webrtc::VideoCodecType codec);
+  ~WebRtcVideoEncoder() override;
+
+  // webrtc::VideoEncoder overrides
+  int32_t InitEncode(const webrtc::VideoCodec* codec_settings,
+                     int32_t number_of_cores,
+                     size_t max_payload_size) override;
+  int32_t RegisterEncodeCompleteCallback(
+      webrtc::EncodedImageCallback* callback) override;
+  int32_t Release() override;
+  int32_t Encode(const webrtc::VideoFrame& frame,
+                 const webrtc::CodecSpecificInfo* codec_specific_info,
+                 const std::vector<webrtc::FrameType>* frame_types) override;
+  int32_t SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
+  int32_t SetRates(uint32_t bitrate, uint32_t framerate) override;
+
+  int SendEncodedFrame(int64_t capture_timestamp_ms,
+                       std::unique_ptr<VideoPacket> pkt);
+  void SetKeyFrameRequestCallback(const base::Closure& key_frame_request);
+  void ClearKeyFrameRequestCallback();
+
+ private:
+  // Protects |encoded_callback_|, |key_frame_request_| and |state_|.
+  base::Lock lock_;
+  State state_;
+  webrtc::EncodedImageCallback* encoded_callback_;
+
+  base::Closure key_frame_request_;
+  webrtc::VideoCodecType video_codec_type_;
+  uint32_t target_bitrate_;
+};
+
+// This is the external encoder factory implementation that is passed to
+// WebRTC at the time of creation of peer connection. The external encoder
+// factory primarily manages creation and destruction of encoder.
+class WebRtcVideoEncoderFactory : public cricket::WebRtcVideoEncoderFactory {
+ public:
+  WebRtcVideoEncoderFactory();
+  ~WebRtcVideoEncoderFactory() override;
+
+  webrtc::VideoEncoder* CreateVideoEncoder(
+      webrtc::VideoCodecType type) override;
+  const std::vector<cricket::WebRtcVideoEncoderFactory::VideoCodec>& codecs()
+      const override;
+
+  // Returns true to directly provide encoded frames to webrtc
+  bool EncoderTypeHasInternalSource(webrtc::VideoCodecType type) const override;
+  void DestroyVideoEncoder(webrtc::VideoEncoder* encoder) override;
+
+  int SendEncodedFrame(int64_t capture_timestamp_ms,
+                       std::unique_ptr<VideoPacket> pkt);
+
+  void SetKeyFrameRequestCallback(const base::Closure& key_frame_request);
+  void ClearKeyFrameRequestCallback();
+
+ private:
+  // Protects |key_frame_request_|.
+  base::Lock lock_;
+  base::Closure key_frame_request_;
+  std::vector<cricket::WebRtcVideoEncoderFactory::VideoCodec> codecs_;
+  std::vector<std::unique_ptr<WebRtcVideoEncoder>> encoders_;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_WEBRTC_VIDEO_ENCODER_H_