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/video/capture/video_capture_types.h"
  15
  16 namespace media {
  17
  18 class VideoFrame;
  19
  20 class MEDIA_EXPORT VideoCapture {
  21  public:
  22   // TODO(wjia): add error codes.
  23   // TODO(wjia): support weak ptr.
  24   // Callbacks provided by client for notification of events.
  25   class MEDIA_EXPORT EventHandler {
  26    public:
  27     // Notify client that video capture has been started.
  28     virtual void OnStarted(VideoCapture* capture) = 0;
  29
  30     // Notify client that video capture has been stopped.
  31     virtual void OnStopped(VideoCapture* capture) = 0;
  32
  33     // Notify client that video capture has been paused.
  34     virtual void OnPaused(VideoCapture* capture) = 0;
  35
  36     // Notify client that video capture has hit some error |error_code|.
  37     virtual void OnError(VideoCapture* capture, int error_code) = 0;
  38
  39     // Notify client that the client has been removed and no more calls will be
  40     // received.
  41     virtual void OnRemoved(VideoCapture* capture) = 0;
  42
  43     // Notify client that a buffer is available.
  44     virtual void OnFrameReady(
  45         VideoCapture* capture,
  46         const scoped_refptr<media::VideoFrame>& frame) = 0;
  47
  48    protected:
  49     virtual ~EventHandler() {}
  50   };
  51
  52   VideoCapture() {}
  53
  54   // Request video capture to start capturing with |params|.
  55   // Also register |handler| with video capture for event handling.
  56   // |handler| must remain valid until it has received |OnRemoved()|.
  57   virtual void StartCapture(EventHandler* handler,
  58                             const VideoCaptureParams& params) = 0;
  59
  60   // Request video capture to stop capturing for client |handler|.
  61   // |handler| must remain valid until it has received |OnRemoved()|.
  62   virtual void StopCapture(EventHandler* handler) = 0;
  63
  64   virtual bool CaptureStarted() = 0;
  65   virtual int CaptureFrameRate() = 0;
  66
  67  protected:
  68   virtual ~VideoCapture() {}
  69
  70  private:
  71   DISALLOW_COPY_AND_ASSIGN(VideoCapture);
  72 };
  73
  74 }  // namespace media
  75
  76 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_H_