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// Copyright (c) 2010 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_HOST_SCREEN_RECORDER_H_
#define REMOTING_HOST_SCREEN_RECORDER_H_
#include <vector>
#include "base/basictypes.h"
#include "base/message_loop.h"
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "base/time.h"
#include "remoting/base/encoder.h"
#include "remoting/host/capturer.h"
#include "remoting/proto/video.pb.h"
namespace remoting {
namespace protocol {
class ConnectionToClient;
} // namespace protocol
class CaptureData;
// A class for controlling and coordinate Capturer, Encoder
// and NetworkChannel in a record session.
//
// THREADING
//
// This class works on three threads, namely capture, encode and network
// thread. The main function of this class is to coordinate and schedule
// capture, encode and transmission of data on different threads.
//
// The following is an example of timeline for operations scheduled.
//
// | CAPTURE ENCODE NETWORK
// | .............
// | . Capture .
// | .............
// | ............
// | . .
// | ............. . .
// | . Capture . . Encode .
// | ............. . .
// | . .
// | ............
// | ............. ............ ..........
// | . Capture . . . . Send .
// | ............. . . ..........
// | . Encode .
// | . .
// | . .
// | ............
// | Time
// v
//
// ScreenRecorder has the following responsibilities:
// 1. Make sure capture and encode occurs no more frequently than |rate|.
// 2. Make sure there is at most one outstanding capture not being encoded.
// 3. Distribute tasks on three threads on a timely fashion to minimize latency.
class ScreenRecorder : public base::RefCountedThreadSafe<ScreenRecorder> {
public:
// Construct a ScreenRecorder. Message loops and threads are provided.
// This object does not own capturer and encoder.
ScreenRecorder(MessageLoop* capture_loop,
MessageLoop* encode_loop,
MessageLoop* network_loop,
Capturer* capturer,
Encoder* encoder);
virtual ~ScreenRecorder();
// Start recording.
void Start();
// Pause the recording session.
void Pause();
// Set the maximum capture rate. This is denoted by number of updates
// in one second. The actual system may run in a slower rate than the maximum
// rate due to various factors, e.g. capture speed, encode speed and network
// conditions.
// This method should be called before Start() is called.
void SetMaxRate(double rate);
// Add a connection to this recording session.
void AddConnection(scoped_refptr<protocol::ConnectionToClient> connection);
// Remove a connection from receiving screen updates.
void RemoveConnection(scoped_refptr<protocol::ConnectionToClient> connection);
// Remove all connections.
void RemoveAllConnections();
private:
// Getters for capturer and encoder.
Capturer* capturer();
Encoder* encoder();
// Capturer thread ----------------------------------------------------------
void DoStart();
void DoPause();
void DoSetRate(double rate);
void DoSetMaxRate(double max_rate);
// Hepler method to schedule next capture using the current rate.
void ScheduleNextCapture();
void DoCapture();
void CaptureDoneCallback(scoped_refptr<CaptureData> capture_data);
void DoFinishEncode();
void DoGetInitInfo(scoped_refptr<protocol::ConnectionToClient> client);
// Network thread -----------------------------------------------------------
void DoStartRateControl();
void DoPauseRateControl();
// Helper method to schedule next rate regulation task.
void ScheduleNextRateControl();
void DoRateControl();
// DoSendUpdate takes ownership of header and is responsible for deleting it.
void DoSendVideoPacket(VideoPacket* packet);
void DoSendInit(scoped_refptr<protocol::ConnectionToClient> connection,
int width, int height);
void DoAddClient(scoped_refptr<protocol::ConnectionToClient> connection);
void DoRemoveClient(scoped_refptr<protocol::ConnectionToClient> connection);
void DoRemoveAllClients();
// Encoder thread -----------------------------------------------------------
void DoEncode(scoped_refptr<CaptureData> capture_data);
// EncodeDataAvailableTask takes ownership of header and is responsible for
// deleting it.
void EncodeDataAvailableTask(VideoPacket* packet);
// Message loops used by this class.
MessageLoop* capture_loop_;
MessageLoop* encode_loop_;
MessageLoop* network_loop_;
// Reference to the capturer. This member is always accessed on the capture
// thread.
scoped_ptr<Capturer> capturer_;
// Reference to the encoder. This member is always accessed on the encode
// thread.
scoped_ptr<Encoder> encoder_;
// A list of clients connected to this hosts.
// This member is always accessed on the NETWORK thread.
// TODO(hclam): Have to scoped_refptr the clients since they have a shorter
// lifetime than this object.
typedef std::vector<scoped_refptr<protocol::ConnectionToClient> >
ConnectionToClientList;
ConnectionToClientList connections_;
// The following members are accessed on the capture thread.
double rate_; // Number of captures to perform every second.
bool started_;
base::Time last_capture_time_; // Saves the time last capture started.
int recordings_; // Count the number of recordings
// (i.e. capture or encode) happening.
// The maximum rate is written on the capture thread and read on the network
// thread.
double max_rate_; // Number of captures to perform every second.
// The following member is accessed on the network thread.
bool rate_control_started_;
DISALLOW_COPY_AND_ASSIGN(ScreenRecorder);
};
} // namespace remoting
#endif // REMOTING_HOST_SCREEN_RECORDER_H_
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