media/capture/thread_safe_capture_oracle.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 MEDIA_CAPTURE_THREAD_SAFE_CAPTURE_ORACLE_H_
   6 #define MEDIA_CAPTURE_THREAD_SAFE_CAPTURE_ORACLE_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/ref_counted.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "media/base/media_export.h"
  13 #include "media/base/video_frame.h"
  14 #include "media/capture/video_capture_oracle.h"
  15 #include "media/video/capture/video_capture_device.h"
  16
  17 namespace media {
  18
  19 struct VideoCaptureParams;
  20 class VideoFrame;
  21
  22 // Thread-safe, refcounted proxy to the VideoCaptureOracle.  This proxy wraps
  23 // the VideoCaptureOracle, which decides which frames to capture, and a
  24 // VideoCaptureDevice::Client, which allocates and receives the captured
  25 // frames, in a lock to synchronize state between the two.
  26 class MEDIA_EXPORT ThreadSafeCaptureOracle
  27     : public base::RefCountedThreadSafe<ThreadSafeCaptureOracle> {
  28  public:
  29   ThreadSafeCaptureOracle(scoped_ptr<VideoCaptureDevice::Client> client,
  30                           const VideoCaptureParams& params,
  31                           bool enable_auto_throttling);
  32
  33   // Called when a captured frame is available or an error has occurred.
  34   // If |success| is true then |frame| is valid and |timestamp| indicates when
  35   // the frame was painted.
  36   // If |success| is false, all other parameters are invalid.
  37   typedef base::Callback<void(const scoped_refptr<VideoFrame>& frame,
  38                               base::TimeTicks timestamp,
  39                               bool success)> CaptureFrameCallback;
  40
  41   bool ObserveEventAndDecideCapture(VideoCaptureOracle::Event event,
  42                                     const gfx::Rect& damage_rect,
  43                                     base::TimeTicks event_time,
  44                                     scoped_refptr<VideoFrame>* storage,
  45                                     CaptureFrameCallback* callback);
  46
  47   base::TimeDelta min_capture_period() const {
  48     return oracle_.min_capture_period();
  49   }
  50
  51   gfx::Size max_frame_size() const {
  52     return params_.requested_format.frame_size;
  53   }
  54
  55   // Returns the current capture resolution.
  56   gfx::Size GetCaptureSize() const;
  57
  58   // Updates capture resolution based on the supplied source size and the
  59   // maximum frame size.
  60   void UpdateCaptureSize(const gfx::Size& source_size);
  61
  62   // Stop new captures from happening (but doesn't forget the client).
  63   void Stop();
  64
  65   // Signal an error to the client.
  66   void ReportError(const std::string& reason);
  67
  68  private:
  69   friend class base::RefCountedThreadSafe<ThreadSafeCaptureOracle>;
  70   virtual ~ThreadSafeCaptureOracle();
  71
  72   // Callback invoked on completion of all captures.
  73   void DidCaptureFrame(
  74       int frame_number,
  75       scoped_ptr<VideoCaptureDevice::Client::Buffer> buffer,
  76       base::TimeTicks capture_begin_time,
  77       base::TimeDelta estimated_frame_duration,
  78       const scoped_refptr<VideoFrame>& frame,
  79       base::TimeTicks timestamp,
  80       bool success);
  81
  82   // Callback invoked once all consumers have finished with a delivered video
  83   // frame.  Consumer feedback signals are scanned from the frame's |metadata|.
  84   void DidConsumeFrame(int frame_number,
  85                        const media::VideoFrameMetadata* metadata);
  86
  87   // Protects everything below it.
  88   mutable base::Lock lock_;
  89
  90   // Recipient of our capture activity.
  91   scoped_ptr<VideoCaptureDevice::Client> client_;
  92
  93   // Makes the decision to capture a frame.
  94   VideoCaptureOracle oracle_;
  95
  96   // The video capture parameters used to construct the oracle proxy.
  97   const VideoCaptureParams params_;
  98 };
  99
 100 }  // namespace media
 101
 102 #endif  // MEDIA_CAPTURE_THREAD_SAFE_CAPTURE_ORACLE_H_