remoting/host/video_frame_recorder.h

   1 // Copyright 2014 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 #ifndef REMOTING_HOST_VIDEO_FRAME_RECORDER_H_
   6 #define REMOTING_HOST_VIDEO_FRAME_RECORDER_H_
   7
   8 #include <stdint.h>
   9 #include <list>
  10
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "base/single_thread_task_runner.h"
  15
  16 namespace webrtc {
  17 class DesktopFrame;
  18 }
  19
  20 namespace remoting {
  21
  22 class VideoEncoder;
  23
  24 // Allows sequences of DesktopFrames passed to a VideoEncoder to be recorded.
  25 //
  26 // VideoFrameRecorder is designed to support applications which use a dedicated
  27 // thread for video encoding, but need to manage that process from a "main"
  28 // or "control" thread.
  29 //
  30 // On the control thread:
  31 // 1. Create the VideoFrameRecorder on the controlling thread.
  32 // 2. Specify the amount of memory that may be used for recording.
  33 // 3. Call WrapVideoEncoder(), passing the actual VideoEncoder that will be
  34 //    used to encode frames.
  35 // 4. Hand the returned wrapper VideoEncoder of to the video encoding thread,
  36 //    to call in place of the actual VideoEncoder.
  37 // 5. Start/stop frame recording as necessary.
  38 // 6. Use NextFrame() to read each recorded frame in sequence.
  39 //
  40 // The wrapper VideoEncoder is designed to be handed off to the video encoding
  41 // thread, and used and torn down there.
  42 //
  43 // The VideoFrameRecorder and VideoEncoder may be torn down in any order; frame
  44 // recording will stop as soon as either is destroyed.
  45
  46 class VideoFrameRecorder {
  47  public:
  48   VideoFrameRecorder();
  49   virtual ~VideoFrameRecorder();
  50
  51   // Wraps the supplied VideoEncoder, returning a replacement VideoEncoder that
  52   // will route frames to the recorder, as well as passing them for encoding.
  53   // The caller must delete the previous recording VideoEncoder, or call
  54   // DetachVideoEncoderWrapper() before calling WrapVideoEncoder() to create
  55   // a new wrapper.
  56   scoped_ptr<VideoEncoder> WrapVideoEncoder(scoped_ptr<VideoEncoder> encoder);
  57
  58   // Detaches the existing VideoEncoder wrapper, stopping it from recording.
  59   void DetachVideoEncoderWrapper();
  60
  61   // Enables/disables frame recording. Frame recording is initially disabled.
  62   void SetEnableRecording(bool enable_recording);
  63
  64   // Sets the maximum number of bytes of pixel data that may be recorded.
  65   // When this maximum is reached older frames will be discard to make space
  66   // for new ones.
  67   void SetMaxContentBytes(int64_t max_content_bytes);
  68
  69   // Pops the next recorded frame in the sequence, and returns it.
  70   scoped_ptr<webrtc::DesktopFrame> NextFrame();
  71
  72  private:
  73   class RecordingVideoEncoder;
  74   friend class RecordingVideoEncoder;
  75
  76   void SetEncoderTaskRunner(scoped_refptr<base::TaskRunner> task_runner);
  77   void RecordFrame(scoped_ptr<webrtc::DesktopFrame> frame);
  78
  79   // The recorded frames, in sequence.
  80   std::list<webrtc::DesktopFrame*> recorded_frames_;
  81
  82   // Size of the recorded frames' content, in bytes.
  83   int64_t content_bytes_;
  84
  85   // Size that recorded frames' content must not exceed.
  86   int64_t max_content_bytes_;
  87
  88   // True if recording is started, false otherwise.
  89   bool enable_recording_;
  90
  91   // Task runner on which the wrapper VideoEncoder is being run.
  92   scoped_refptr<base::TaskRunner> encoder_task_runner_;
  93
  94   // Weak reference to the wrapper VideoEncoder, to use to control it.
  95   base::WeakPtr<RecordingVideoEncoder> recording_encoder_;
  96
  97   scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner_;
  98   base::WeakPtrFactory<VideoFrameRecorder> weak_factory_;
  99
 100   DISALLOW_COPY_AND_ASSIGN(VideoFrameRecorder);
 101 };
 102
 103 }  // namespace remoting
 104
 105 #endif  // REMOTING_HOST_VIDEO_FRAME_RECORDER_H_