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// Copyright 2015 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_VIDEO_FRAME_PUMP_H_
#define REMOTING_PROTOCOL_VIDEO_FRAME_PUMP_H_
#include <stddef.h>
#include <stdint.h>
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/scoped_vector.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "remoting/codec/video_encoder.h"
#include "remoting/proto/video.pb.h"
#include "remoting/protocol/capture_scheduler.h"
#include "remoting/protocol/video_stream.h"
#include "third_party/webrtc/modules/desktop_capture/desktop_capturer.h"
namespace base {
class SingleThreadTaskRunner;
} // namespace base
namespace remoting {
namespace protocol {
class VideoFeedbackStub;
class VideoStub;
// Class responsible for scheduling frame captures from a screen capturer.,
// delivering them to a VideoEncoder to encode, and
// finally passing the encoded video packets to the specified VideoStub to send
// on the network.
//
// THREADING
//
// This class is supplied TaskRunners to use for capture, encode and network
// operations. Capture, encode and network transmission tasks are interleaved
// as illustrated below:
//
// | CAPTURE ENCODE NETWORK
// | .............
// | . Capture .
// | .............
// | ............
// | . .
// | ............. . .
// | . Capture . . Encode .
// | ............. . .
// | . .
// | ............
// | ............. ............ ..........
// | . Capture . . . . Send .
// | ............. . . ..........
// | . Encode .
// | . .
// | . .
// | ............
// | Time
// v
//
// VideoFramePump would ideally schedule captures so as to saturate the slowest
// of the capture, encode and network processes. However, it also needs to
// rate-limit captures to avoid overloading the host system, either by consuming
// too much CPU, or hogging the host's graphics subsystem.
class VideoFramePump : public VideoStream,
public webrtc::DesktopCapturer::Callback {
public:
// Enables timestamps for generated frames. Used for testing.
static void EnableTimestampsForTests();
// Creates a VideoFramePump running capture, encode and network tasks on the
// supplied TaskRunners. Video will be pumped to |video_stub|, which must
// outlive the pump..
VideoFramePump(
scoped_refptr<base::SingleThreadTaskRunner> encode_task_runner,
scoped_ptr<webrtc::DesktopCapturer> capturer,
scoped_ptr<VideoEncoder> encoder,
protocol::VideoStub* video_stub);
~VideoFramePump() override;
// VideoStream interface.
void Pause(bool pause) override;
void OnInputEventReceived(int64_t event_timestamp) override;
void SetLosslessEncode(bool want_lossless) override;
void SetLosslessColor(bool want_lossless) override;
void SetSizeCallback(const SizeCallback& size_callback) override;
protocol::VideoFeedbackStub* video_feedback_stub() {
return &capture_scheduler_;
}
private:
struct FrameTimestamps {
FrameTimestamps();
~FrameTimestamps();
// The following two fields are set only for one frame after each incoming
// input event. |input_event_client_timestamp| is event timestamp
// received from the client. |input_event_received_time| is local time when
// the event was received.
int64_t input_event_client_timestamp = -1;
base::TimeTicks input_event_received_time;
base::TimeTicks capture_started_time;
base::TimeTicks capture_ended_time;
base::TimeTicks encode_started_time;
base::TimeTicks encode_ended_time;
base::TimeTicks can_send_time;
};
struct PacketWithTimestamps {
PacketWithTimestamps(scoped_ptr<VideoPacket> packet,
scoped_ptr<FrameTimestamps> timestamps);
~PacketWithTimestamps();
scoped_ptr<VideoPacket> packet;
scoped_ptr<FrameTimestamps> timestamps;
};
// webrtc::DesktopCapturer::Callback interface.
webrtc::SharedMemory* CreateSharedMemory(size_t size) override;
void OnCaptureCompleted(webrtc::DesktopFrame* frame) override;
// Callback for CaptureScheduler.
void CaptureNextFrame();
// Task running on the encoder thread to encode the |frame|.
static scoped_ptr<PacketWithTimestamps> EncodeFrame(
VideoEncoder* encoder,
scoped_ptr<webrtc::DesktopFrame> frame,
scoped_ptr<FrameTimestamps> timestamps);
// Task called when a frame has finished encoding.
void OnFrameEncoded(scoped_ptr<PacketWithTimestamps> packet);
// Sends |packet| to the client.
void SendPacket(scoped_ptr<PacketWithTimestamps> packet);
// Helper called from SendPacket() to calculate timing fields in the |packet|
// before sending it.
void UpdateFrameTimers(VideoPacket* packet, FrameTimestamps* timestamps);
// Callback passed to |video_stub_|.
void OnVideoPacketSent();
// Called by |keep_alive_timer_|.
void SendKeepAlivePacket();
// Callback for |video_stub_| called after a keep-alive packet is sent.
void OnKeepAlivePacketSent();
// Task runner used to run |encoder_|.
scoped_refptr<base::SingleThreadTaskRunner> encode_task_runner_;
// Capturer used to capture the screen.
scoped_ptr<webrtc::DesktopCapturer> capturer_;
// Used to encode captured frames. Always accessed on the encode thread.
scoped_ptr<VideoEncoder> encoder_;
// Interface through which video frames are passed to the client.
protocol::VideoStub* video_stub_;
SizeCallback size_callback_;
webrtc::DesktopSize frame_size_;
// Timer used to ensure that we send empty keep-alive frames to the client
// even when the video stream is paused or encoder is busy.
base::Timer keep_alive_timer_;
// CaptureScheduler calls CaptureNextFrame() whenever a new frame needs to be
// captured.
CaptureScheduler capture_scheduler_;
// Timestamps for the frame to be captured next.
scoped_ptr<FrameTimestamps> next_frame_timestamps_;
// Timestamps for the frame that's being captured.
scoped_ptr<FrameTimestamps> captured_frame_timestamps_;
bool send_pending_ = false;
ScopedVector<PacketWithTimestamps> pending_packets_;
base::ThreadChecker thread_checker_;
base::WeakPtrFactory<VideoFramePump> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(VideoFramePump);
};
} // namespace protocol
} // namespace remoting
#endif // REMOTING_PROTOCOL_VIDEO_FRAME_PUMP_H_
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