media/video/capture/video_capture.h

   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_