src/remoting/host/video_scheduler.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/host/video_scheduler.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/bind.h"
  10 #include "base/callback.h"
  11 #include "base/logging.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/message_loop/message_loop_proxy.h"
  14 #include "base/stl_util.h"
  15 #include "base/sys_info.h"
  16 #include "base/time/time.h"
  17 #include "remoting/proto/control.pb.h"
  18 #include "remoting/proto/internal.pb.h"
  19 #include "remoting/proto/video.pb.h"
  20 #include "remoting/protocol/cursor_shape_stub.h"
  21 #include "remoting/protocol/message_decoder.h"
  22 #include "remoting/protocol/video_stub.h"
  23 #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
  24 #include "third_party/webrtc/modules/desktop_capture/mouse_cursor_shape.h"
  25 #include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
  26
  27 namespace remoting {
  28
  29 // Maximum number of frames that can be processed simultaneously.
  30 // TODO(hclam): Move this value to CaptureScheduler.
  31 static const int kMaxPendingFrames = 2;
  32
  33 VideoScheduler::VideoScheduler(
  34     scoped_refptr<base::SingleThreadTaskRunner> capture_task_runner,
  35     scoped_refptr<base::SingleThreadTaskRunner> encode_task_runner,
  36     scoped_refptr<base::SingleThreadTaskRunner> network_task_runner,
  37     scoped_ptr<webrtc::ScreenCapturer> capturer,
  38     scoped_ptr<VideoEncoder> encoder,
  39     protocol::CursorShapeStub* cursor_stub,
  40     protocol::VideoStub* video_stub)
  41     : capture_task_runner_(capture_task_runner),
  42       encode_task_runner_(encode_task_runner),
  43       network_task_runner_(network_task_runner),
  44       capturer_(capturer.Pass()),
  45       encoder_(encoder.Pass()),
  46       cursor_stub_(cursor_stub),
  47       video_stub_(video_stub),
  48       pending_frames_(0),
  49       capture_pending_(false),
  50       did_skip_frame_(false),
  51       is_paused_(false),
  52       sequence_number_(0) {
  53   DCHECK(network_task_runner_->BelongsToCurrentThread());
  54   DCHECK(capturer_);
  55   DCHECK(encoder_);
  56   DCHECK(cursor_stub_);
  57   DCHECK(video_stub_);
  58 }
  59
  60 // Public methods --------------------------------------------------------------
  61
  62 webrtc::SharedMemory* VideoScheduler::CreateSharedMemory(size_t size) {
  63   return NULL;
  64 }
  65
  66 void VideoScheduler::OnCaptureCompleted(webrtc::DesktopFrame* frame) {
  67   DCHECK(capture_task_runner_->BelongsToCurrentThread());
  68
  69   capture_pending_ = false;
  70
  71   scoped_ptr<webrtc::DesktopFrame> owned_frame(frame);
  72
  73   if (frame) {
  74     scheduler_.RecordCaptureTime(
  75         base::TimeDelta::FromMilliseconds(frame->capture_time_ms()));
  76   }
  77
  78   encode_task_runner_->PostTask(
  79       FROM_HERE, base::Bind(&VideoScheduler::EncodeFrame, this,
  80                             base::Passed(&owned_frame), sequence_number_));
  81
  82   // If a frame was skipped, try to capture it again.
  83   if (did_skip_frame_) {
  84     capture_task_runner_->PostTask(
  85         FROM_HERE, base::Bind(&VideoScheduler::CaptureNextFrame, this));
  86   }
  87 }
  88
  89 void VideoScheduler::OnCursorShapeChanged(
  90     webrtc::MouseCursorShape* cursor_shape) {
  91   DCHECK(capture_task_runner_->BelongsToCurrentThread());
  92
  93   scoped_ptr<webrtc::MouseCursorShape> owned_cursor(cursor_shape);
  94
  95   // Do nothing if the scheduler is being stopped.
  96   if (!capturer_)
  97     return;
  98
  99   scoped_ptr<protocol::CursorShapeInfo> cursor_proto(
 100       new protocol::CursorShapeInfo());
 101   cursor_proto->set_width(cursor_shape->size.width());
 102   cursor_proto->set_height(cursor_shape->size.height());
 103   cursor_proto->set_hotspot_x(cursor_shape->hotspot.x());
 104   cursor_proto->set_hotspot_y(cursor_shape->hotspot.y());
 105   cursor_proto->set_data(cursor_shape->data);
 106
 107   network_task_runner_->PostTask(
 108       FROM_HERE, base::Bind(&VideoScheduler::SendCursorShape, this,
 109                             base::Passed(&cursor_proto)));
 110 }
 111
 112 void VideoScheduler::Start() {
 113   DCHECK(network_task_runner_->BelongsToCurrentThread());
 114
 115   capture_task_runner_->PostTask(
 116       FROM_HERE, base::Bind(&VideoScheduler::StartOnCaptureThread, this));
 117 }
 118
 119 void VideoScheduler::Stop() {
 120   DCHECK(network_task_runner_->BelongsToCurrentThread());
 121
 122   // Clear stubs to prevent further updates reaching the client.
 123   cursor_stub_ = NULL;
 124   video_stub_ = NULL;
 125
 126   capture_task_runner_->PostTask(FROM_HERE,
 127       base::Bind(&VideoScheduler::StopOnCaptureThread, this));
 128 }
 129
 130 void VideoScheduler::Pause(bool pause) {
 131   if (!capture_task_runner_->BelongsToCurrentThread()) {
 132     DCHECK(network_task_runner_->BelongsToCurrentThread());
 133     capture_task_runner_->PostTask(
 134         FROM_HERE, base::Bind(&VideoScheduler::Pause, this, pause));
 135     return;
 136   }
 137
 138   if (is_paused_ != pause) {
 139     is_paused_ = pause;
 140
 141     // Restart captures if we're resuming and there are none scheduled.
 142     if (!is_paused_ && capture_timer_ && !capture_timer_->IsRunning())
 143       CaptureNextFrame();
 144   }
 145 }
 146
 147 void VideoScheduler::UpdateSequenceNumber(int64 sequence_number) {
 148   if (!capture_task_runner_->BelongsToCurrentThread()) {
 149     DCHECK(network_task_runner_->BelongsToCurrentThread());
 150     capture_task_runner_->PostTask(
 151         FROM_HERE, base::Bind(&VideoScheduler::UpdateSequenceNumber,
 152                               this, sequence_number));
 153     return;
 154   }
 155
 156   sequence_number_ = sequence_number;
 157 }
 158
 159 // Private methods -----------------------------------------------------------
 160
 161 VideoScheduler::~VideoScheduler() {
 162 }
 163
 164 // Capturer thread -------------------------------------------------------------
 165
 166 void VideoScheduler::StartOnCaptureThread() {
 167   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 168   DCHECK(!capture_timer_);
 169
 170   // Start the capturer and let it notify us if cursor shape changes.
 171   capturer_->SetMouseShapeObserver(this);
 172   capturer_->Start(this);
 173
 174   capture_timer_.reset(new base::OneShotTimer<VideoScheduler>());
 175
 176   // Capture first frame immedately.
 177   CaptureNextFrame();
 178 }
 179
 180 void VideoScheduler::StopOnCaptureThread() {
 181   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 182
 183   // This doesn't deleted already captured frames, so encoder can keep using the
 184   // frames that were captured previously.
 185   capturer_.reset();
 186
 187   // |capture_timer_| must be destroyed on the thread on which it is used.
 188   capture_timer_.reset();
 189 }
 190
 191 void VideoScheduler::ScheduleNextCapture() {
 192   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 193
 194   capture_timer_->Start(FROM_HERE,
 195                         scheduler_.NextCaptureDelay(),
 196                         this,
 197                         &VideoScheduler::CaptureNextFrame);
 198 }
 199
 200 void VideoScheduler::CaptureNextFrame() {
 201   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 202
 203   // If we are stopping (|capturer_| is NULL), or paused, then don't capture.
 204   if (!capturer_ || is_paused_)
 205     return;
 206
 207   // Make sure we have at most two outstanding recordings. We can simply return
 208   // if we can't make a capture now, the next capture will be started by the
 209   // end of an encode operation.
 210   if (pending_frames_ >= kMaxPendingFrames || capture_pending_) {
 211     did_skip_frame_ = true;
 212     return;
 213   }
 214
 215   did_skip_frame_ = false;
 216
 217   // At this point we are going to perform one capture so save the current time.
 218   pending_frames_++;
 219   DCHECK_LE(pending_frames_, kMaxPendingFrames);
 220
 221   // Before doing a capture schedule for the next one.
 222   ScheduleNextCapture();
 223
 224   capture_pending_ = true;
 225
 226   // And finally perform one capture.
 227   capturer_->Capture(webrtc::DesktopRegion());
 228 }
 229
 230 void VideoScheduler::FrameCaptureCompleted() {
 231   DCHECK(capture_task_runner_->BelongsToCurrentThread());
 232
 233   // Decrement the pending capture count.
 234   pending_frames_--;
 235   DCHECK_GE(pending_frames_, 0);
 236
 237   // If we've skipped a frame capture because too we had too many captures
 238   // pending then schedule one now.
 239   if (did_skip_frame_)
 240     CaptureNextFrame();
 241 }
 242
 243 // Network thread --------------------------------------------------------------
 244
 245 void VideoScheduler::SendVideoPacket(scoped_ptr<VideoPacket> packet) {
 246   DCHECK(network_task_runner_->BelongsToCurrentThread());
 247
 248   if (!video_stub_)
 249     return;
 250
 251   video_stub_->ProcessVideoPacket(
 252       packet.Pass(), base::Bind(&VideoScheduler::VideoFrameSentCallback, this));
 253 }
 254
 255 void VideoScheduler::VideoFrameSentCallback() {
 256   DCHECK(network_task_runner_->BelongsToCurrentThread());
 257
 258   if (!video_stub_)
 259     return;
 260
 261   capture_task_runner_->PostTask(
 262       FROM_HERE, base::Bind(&VideoScheduler::FrameCaptureCompleted, this));
 263 }
 264
 265 void VideoScheduler::SendCursorShape(
 266     scoped_ptr<protocol::CursorShapeInfo> cursor_shape) {
 267   DCHECK(network_task_runner_->BelongsToCurrentThread());
 268
 269   if (!cursor_stub_)
 270     return;
 271
 272   cursor_stub_->SetCursorShape(*cursor_shape);
 273 }
 274
 275 // Encoder thread --------------------------------------------------------------
 276
 277 void VideoScheduler::EncodeFrame(
 278     scoped_ptr<webrtc::DesktopFrame> frame,
 279     int64 sequence_number) {
 280   DCHECK(encode_task_runner_->BelongsToCurrentThread());
 281
 282   // If there is nothing to encode then send an empty keep-alive packet.
 283   if (!frame || frame->updated_region().is_empty()) {
 284     scoped_ptr<VideoPacket> packet(new VideoPacket());
 285     packet->set_client_sequence_number(sequence_number);
 286     network_task_runner_->PostTask(
 287         FROM_HERE, base::Bind(&VideoScheduler::SendVideoPacket, this,
 288                               base::Passed(&packet)));
 289     capture_task_runner_->DeleteSoon(FROM_HERE, frame.release());
 290     return;
 291   }
 292
 293   scoped_ptr<VideoPacket> packet = encoder_->Encode(*frame);
 294   packet->set_client_sequence_number(sequence_number);
 295
 296   // Destroy the frame before sending |packet| because SendVideoPacket() may
 297   // trigger another frame to be captured, and the screen capturer expects the
 298   // old frame to be freed by then.
 299   frame.reset();
 300
 301   scheduler_.RecordEncodeTime(
 302       base::TimeDelta::FromMilliseconds(packet->encode_time_ms()));
 303   network_task_runner_->PostTask(
 304       FROM_HERE, base::Bind(&VideoScheduler::SendVideoPacket, this,
 305                             base::Passed(&packet)));
 306 }
 307
 308 }  // namespace remoting