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      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 // Windows specific implementation of VideoCaptureDevice.
      6 // DirectShow is used for capturing. DirectShow provide its own threads
      7 // for capturing.
      8 
      9 #ifndef MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_
     10 #define MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_
     11 
     12 // Avoid including strsafe.h via dshow as it will cause build warnings.
     13 #define NO_DSHOW_STRSAFE
     14 #include <dshow.h>
     15 
     16 #include <map>
     17 #include <string>
     18 
     19 #include "base/threading/non_thread_safe.h"
     20 #include "base/threading/thread.h"
     21 #include "base/win/scoped_comptr.h"
     22 #include "media/video/capture/video_capture_device.h"
     23 #include "media/video/capture/video_capture_types.h"
     24 #include "media/video/capture/win/capability_list_win.h"
     25 #include "media/video/capture/win/sink_filter_win.h"
     26 #include "media/video/capture/win/sink_input_pin_win.h"
     27 
     28 namespace media {
     29 
     30 // All the methods in the class can only be run on a COM initialized thread.
     31 class VideoCaptureDeviceWin
     32     : public base::NonThreadSafe,
     33       public VideoCaptureDevice,
     34       public SinkFilterObserver {
     35  public:
     36   // A utility class that wraps the AM_MEDIA_TYPE type and guarantees that
     37   // we free the structure when exiting the scope.  DCHECKing is also done to
     38   // avoid memory leaks.
     39   class ScopedMediaType {
     40    public:
     41     ScopedMediaType() : media_type_(NULL) {}
     42     ~ScopedMediaType() { Free(); }
     43 
     44     AM_MEDIA_TYPE* operator->() { return media_type_; }
     45     AM_MEDIA_TYPE* get() { return media_type_; }
     46     void Free();
     47     AM_MEDIA_TYPE** Receive();
     48 
     49    private:
     50     void FreeMediaType(AM_MEDIA_TYPE* mt);
     51     void DeleteMediaType(AM_MEDIA_TYPE* mt);
     52 
     53     AM_MEDIA_TYPE* media_type_;
     54   };
     55 
     56   static HRESULT GetDeviceFilter(const Name& device_name,
     57                                  IBaseFilter** filter);
     58   static bool PinMatchesCategory(IPin* pin, REFGUID category);
     59   static base::win::ScopedComPtr<IPin> GetPin(IBaseFilter* filter,
     60                                               PIN_DIRECTION pin_dir,
     61                                               REFGUID category);
     62   static VideoPixelFormat TranslateMediaSubtypeToPixelFormat(
     63       const GUID& sub_type);
     64 
     65   explicit VideoCaptureDeviceWin(const Name& device_name);
     66   virtual ~VideoCaptureDeviceWin();
     67   // Opens the device driver for this device.
     68   bool Init();
     69 
     70   // VideoCaptureDevice implementation.
     71   virtual void AllocateAndStart(
     72       const VideoCaptureParams& params,
     73       scoped_ptr<VideoCaptureDevice::Client> client) OVERRIDE;
     74   virtual void StopAndDeAllocate() OVERRIDE;
     75 
     76  private:
     77   enum InternalState {
     78     kIdle,  // The device driver is opened but camera is not in use.
     79     kCapturing,  // Video is being captured.
     80     kError  // Error accessing HW functions.
     81             // User needs to recover by destroying the object.
     82   };
     83 
     84   // Implements SinkFilterObserver.
     85   virtual void FrameReceived(const uint8* buffer, int length);
     86 
     87   bool CreateCapabilityMap();
     88   void SetAntiFlickerInCaptureFilter();
     89   void SetErrorState(const std::string& reason);
     90 
     91   Name device_name_;
     92   InternalState state_;
     93   scoped_ptr<VideoCaptureDevice::Client> client_;
     94 
     95   base::win::ScopedComPtr<IBaseFilter> capture_filter_;
     96   base::win::ScopedComPtr<IGraphBuilder> graph_builder_;
     97   base::win::ScopedComPtr<IMediaControl> media_control_;
     98   base::win::ScopedComPtr<IPin> input_sink_pin_;
     99   base::win::ScopedComPtr<IPin> output_capture_pin_;
    100   // Used when using a MJPEG decoder.
    101   base::win::ScopedComPtr<IBaseFilter> mjpg_filter_;
    102   base::win::ScopedComPtr<IPin> input_mjpg_pin_;
    103   base::win::ScopedComPtr<IPin> output_mjpg_pin_;
    104 
    105   scoped_refptr<SinkFilter> sink_filter_;
    106 
    107   // Map of all capabilities this device support.
    108   CapabilityList capabilities_;
    109   VideoCaptureFormat capture_format_;
    110 
    111   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoCaptureDeviceWin);
    112 };
    113 
    114 }  // namespace media
    115 
    116 #endif  // MEDIA_VIDEO_CAPTURE_WIN_VIDEO_CAPTURE_DEVICE_WIN_H_
    117