blob: e07affe27ff38cd922e45230afa9a3342ef453e6 [file] [log] [blame]
// 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.
#include <stdint.h>
#include "base/callback.h"
#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "remoting/base/running_samples.h"
#include "remoting/protocol/video_feedback_stub.h"
namespace remoting {
class VideoPacket;
namespace protocol {
// CaptureScheduler is used by the VideoFramePump to schedule frame capturer,
// taking into account capture delay, encoder delay, network bandwidth, etc.
// It implements VideoFeedbackStub to receive frame acknowledgments from the
// client.
// It attempts to achieve the following goals when scheduling frames:
// - Keep round-trip latency as low a possible.
// - Parallelize capture, encode and transmission, to achieve frame rate as
// close to the target of 30fps as possible.
// - Limit CPU usage to 50%.
class CaptureScheduler : public VideoFeedbackStub {
explicit CaptureScheduler(const base::Closure& capture_closure);
~CaptureScheduler() override;
// Starts the scheduler.
void Start();
// Pauses or unpauses the stream.
void Pause(bool pause);
// Notifies the scheduler that a capture has been completed.
void OnCaptureCompleted();
// Notifies the scheduler that a frame has been encoded. The scheduler can
// change |packet| if necessary, e.g. set |frame_id|.
void OnFrameEncoded(VideoPacket* packet);
// Notifies the scheduler that a frame has been sent.
void OnFrameSent();
// VideoFeedbackStub interface.
void ProcessVideoAck(std::unique_ptr<VideoAck> video_ack) override;
// Sets minimum interval between frames.
void set_minimum_interval(base::TimeDelta minimum_interval) {
minimum_interval_ = minimum_interval;
// Helper functions for tests.
void SetTickClockForTest(const base::TickClock* tick_clock);
void SetTimerForTest(std::unique_ptr<base::OneShotTimer> timer);
void SetNumOfProcessorsForTest(int num_of_processors);
// Schedules |capture_timer_| to call CaptureNextFrame() at appropriate time.
// Doesn't do anything if next frame cannot be captured yet (e.g. because
// there are too many frames being processed).
void ScheduleNextCapture();
// Called by |capture_timer_|. Calls |capture_closure_| to start capturing a
// new frame.
void CaptureNextFrame();
base::Closure capture_closure_;
const base::TickClock* tick_clock_;
// Timer used to schedule CaptureNextFrame().
std::unique_ptr<base::OneShotTimer> capture_timer_;
// Minimum interval between frames that determines maximum possible framerate.
base::TimeDelta minimum_interval_;
int num_of_processors_;
RunningSamples capture_time_;
RunningSamples encode_time_;
// Number of frames pending encoding.
int num_encoding_frames_;
// Number of outgoing frames for which we haven't received an acknowledgment.
int num_unacknowledged_frames_;
// Set to true when capture is pending.
bool capture_pending_;
// Time at which the last capture started. Used to schedule |capture_timer_|.
base::TimeTicks last_capture_started_time_;
bool is_paused_;
// Frame ID to be assigned to the next outgoing video frame.
uint32_t next_frame_id_;
base::ThreadChecker thread_checker_;
} // namespace protocol
} // namespace remoting