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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 // This file contains abstract classes used for media filter to handle video
      6 // capture devices.
      7 
      8 #ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_H_
      9 #define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_H_
     10 
     11 #include "base/memory/ref_counted.h"
     12 #include "base/time/time.h"
     13 #include "media/base/media_export.h"
     14 #include "media/base/video_frame.h"
     15 #include "media/video/capture/video_capture_types.h"
     16 
     17 namespace media {
     18 
     19 class MEDIA_EXPORT VideoCapture {
     20  public:
     21   // TODO(wjia): consider merging with media::VideoFrame if possible.
     22   class VideoFrameBuffer : public base::RefCountedThreadSafe<VideoFrameBuffer> {
     23    public:
     24     VideoFrameBuffer()
     25         : width(0),
     26           height(0),
     27           stride(0),
     28           buffer_size(0),
     29           memory_pointer(NULL) {}
     30 
     31     int width;
     32     int height;
     33     int stride;
     34     size_t buffer_size;
     35     uint8* memory_pointer;
     36     base::Time timestamp;
     37 
     38    private:
     39     friend class base::RefCountedThreadSafe<VideoFrameBuffer>;
     40     ~VideoFrameBuffer() {}
     41 
     42     DISALLOW_COPY_AND_ASSIGN(VideoFrameBuffer);
     43   };
     44 
     45   // TODO(wjia): add error codes.
     46   // TODO(wjia): support weak ptr.
     47   // Callbacks provided by client for notification of events.
     48   class MEDIA_EXPORT EventHandler {
     49    public:
     50     // Notify client that video capture has been started.
     51     virtual void OnStarted(VideoCapture* capture) = 0;
     52 
     53     // Notify client that video capture has been stopped.
     54     virtual void OnStopped(VideoCapture* capture) = 0;
     55 
     56     // Notify client that video capture has been paused.
     57     virtual void OnPaused(VideoCapture* capture) = 0;
     58 
     59     // Notify client that video capture has hit some error |error_code|.
     60     virtual void OnError(VideoCapture* capture, int error_code) = 0;
     61 
     62     // Notify client that the client has been removed and no more calls will be
     63     // received.
     64     virtual void OnRemoved(VideoCapture* capture) = 0;
     65 
     66     // Notify client that a buffer is available.
     67     virtual void OnBufferReady(VideoCapture* capture,
     68                                scoped_refptr<VideoFrameBuffer> buffer) = 0;
     69 
     70     // Notify client about device info.
     71     virtual void OnDeviceInfoReceived(
     72         VideoCapture* capture,
     73         const VideoCaptureParams& device_info) = 0;
     74 
     75     // Notify client about the newly changed device info.
     76     virtual void OnDeviceInfoChanged(
     77         VideoCapture* capture,
     78         const VideoCaptureParams& device_info) {};
     79 
     80    protected:
     81     virtual ~EventHandler() {}
     82   };
     83 
     84   VideoCapture() {}
     85 
     86   // Request video capture to start capturing with |capability|.
     87   // Also register |handler| with video capture for event handling.
     88   // |handler| must remain valid until it has received |OnRemoved()|.
     89   virtual void StartCapture(EventHandler* handler,
     90                             const VideoCaptureCapability& capability) = 0;
     91 
     92   // Request video capture to stop capturing for client |handler|.
     93   // |handler| must remain valid until it has received |OnRemoved()|.
     94   virtual void StopCapture(EventHandler* handler) = 0;
     95 
     96   // Feed buffer to video capture when done with it.
     97   virtual void FeedBuffer(scoped_refptr<VideoFrameBuffer> buffer) = 0;
     98 
     99   virtual bool CaptureStarted() = 0;
    100   virtual int CaptureWidth() = 0;
    101   virtual int CaptureHeight() = 0;
    102   virtual int CaptureFrameRate() = 0;
    103 
    104  protected:
    105   virtual ~VideoCapture() {}
    106 
    107  private:
    108   DISALLOW_COPY_AND_ASSIGN(VideoCapture);
    109 };
    110 
    111 }  // namespace media
    112 
    113 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_H_
    114