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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 // | 4 // |
5 // VideoCaptureDevice is the abstract base class for realizing video capture | 5 // VideoCaptureDevice is the abstract base class for realizing video capture |
6 // device support in Chromium. It provides the interface for OS dependent | 6 // device support in Chromium. It provides the interface for OS dependent |
7 // implementations. | 7 // implementations. |
8 // The class is created and functions are invoked on a thread owned by | 8 // The class is created and functions are invoked on a thread owned by |
9 // VideoCaptureManager. Capturing is done on other threads, depending on the OS | 9 // VideoCaptureManager. Capturing is done on other threads, depending on the OS |
10 // specific implementation. | 10 // specific implementation. |
11 | 11 |
12 #ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ | 12 #ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ |
13 #define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ | 13 #define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ |
14 | 14 |
15 #include <list> | 15 #include <list> |
16 #include <string> | 16 #include <string> |
17 | 17 |
18 #include "base/logging.h" | 18 #include "base/logging.h" |
| 19 #include "base/memory/ref_counted.h" |
| 20 #include "base/memory/scoped_ptr.h" |
19 #include "base/time/time.h" | 21 #include "base/time/time.h" |
20 #include "media/base/media_export.h" | 22 #include "media/base/media_export.h" |
21 #include "media/video/capture/video_capture_types.h" | 23 #include "media/video/capture/video_capture_types.h" |
22 | 24 |
23 namespace media { | 25 namespace media { |
24 | 26 |
25 class MEDIA_EXPORT VideoCaptureDevice { | 27 class MEDIA_EXPORT VideoCaptureDevice { |
26 public: | 28 public: |
27 // Represents a capture device name and ID. | 29 // Represents a capture device name and ID. |
28 // You should not create an instance of this class directly by e.g. setting | 30 // You should not create an instance of this class directly by e.g. setting |
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113 : public NON_EXPORTED_BASE(std::list<Name>) { | 115 : public NON_EXPORTED_BASE(std::list<Name>) { |
114 public: | 116 public: |
115 // Returns NULL if no entry was found by that ID. | 117 // Returns NULL if no entry was found by that ID. |
116 Name* FindById(const std::string& id); | 118 Name* FindById(const std::string& id); |
117 | 119 |
118 // Allow generated copy constructor and assignment. | 120 // Allow generated copy constructor and assignment. |
119 }; | 121 }; |
120 | 122 |
121 class MEDIA_EXPORT Client { | 123 class MEDIA_EXPORT Client { |
122 public: | 124 public: |
| 125 // Memory buffer returned by Client::ReserveOutputBuffer(). |
| 126 class Buffer : public base::RefCountedThreadSafe<Buffer> { |
| 127 public: |
| 128 int id() const { return id_; } |
| 129 void* data() const { return data_; } |
| 130 size_t size() const { return size_; } |
| 131 |
| 132 protected: |
| 133 friend class base::RefCountedThreadSafe<Buffer>; |
| 134 |
| 135 Buffer(int id, void* data, size_t size) |
| 136 : id_(id), data_(data), size_(size) {} |
| 137 virtual ~Buffer() {} |
| 138 |
| 139 const int id_; |
| 140 void* const data_; |
| 141 const size_t size_; |
| 142 }; |
| 143 |
123 virtual ~Client() {} | 144 virtual ~Client() {} |
124 | 145 |
125 // Reserve an output buffer into which a video frame can be captured | 146 // Reserve an output buffer into which contents can be captured directly. |
126 // directly. If all buffers are currently busy, returns NULL. | 147 // The returned Buffer will always be allocated with a memory size suitable |
| 148 // for holding a packed video frame of |format| format, of |dimensions| |
| 149 // dimensions. It is permissible for |dimensions| to be zero; in which |
| 150 // case the returned Buffer does not guarantee memory backing, but functions |
| 151 // as a reservation for external input for the purposes of buffer |
| 152 // throttling. |
127 // | 153 // |
128 // The returned VideoFrames will always be allocated with a YV12 format and | 154 // The output buffer stays reserved for use until the Buffer object is |
129 // have dimensions matching |size|. It is the VideoCaptureDevice's | 155 // destroyed. |
130 // responsibility to obey whatever stride and memory layout are indicated on | 156 virtual scoped_refptr<Buffer> ReserveOutputBuffer( |
131 // the returned VideoFrame object. | 157 media::VideoFrame::Format format, |
132 // | 158 const gfx::Size& dimensions) = 0; |
133 // The output buffer stays reserved for use by the calling | |
134 // VideoCaptureDevice until either the last reference to the VideoFrame is | |
135 // released, or until the buffer is passed back to the Client's | |
136 // OnIncomingCapturedFrame() method. | |
137 virtual scoped_refptr<media::VideoFrame> ReserveOutputBuffer( | |
138 const gfx::Size& size) = 0; | |
139 | 159 |
140 // Captured a new video frame as a raw buffer. The size, color format, and | 160 // Captured a new video frame as a raw buffer. The size, color format, and |
141 // layout are taken from the parameters specified by an earlier call to | 161 // layout are taken from the parameters specified by an earlier call to |
142 // OnFrameInfo(). |data| must be packed, with no padding between rows and/or | 162 // OnFrameInfo(). |data| must be packed, with no padding between rows and/or |
143 // color planes. | 163 // color planes. |
144 // | 164 // |
145 // This method will try to reserve an output buffer and copy from |data| | 165 // This method will try to reserve an output buffer and copy from |data| |
146 // into the output buffer. If no output buffer is available, the frame will | 166 // into the output buffer. If no output buffer is available, the frame will |
147 // be silently dropped. | 167 // be silently dropped. |
148 virtual void OnIncomingCapturedFrame( | 168 virtual void OnIncomingCapturedFrame( |
149 const uint8* data, | 169 const uint8* data, |
150 int length, | 170 int length, |
151 base::Time timestamp, | 171 base::Time timestamp, |
152 int rotation, // Clockwise. | 172 int rotation, // Clockwise. |
153 bool flip_vert, | 173 bool flip_vert, |
154 bool flip_horiz, | 174 bool flip_horiz, |
155 const VideoCaptureCapability& frame_info) = 0; | 175 const VideoCaptureCapability& frame_info) = 0; |
156 | 176 |
157 // Captured a new video frame, held in a VideoFrame container. | 177 // Captured a new video frame, held in |buffer|. |
158 // | 178 // |
159 // If |frame| was created via the ReserveOutputBuffer() mechanism, then the | 179 // As the frame is backed by a reservation returned by |
160 // frame delivery is guaranteed (it will not be silently dropped), and | 180 // ReserveOutputBuffer(), delivery is guaranteed and will require no |
161 // delivery will require no additional copies in the browser process. For | 181 // additional copies in the browser process. |dimensions| indicates the |
162 // such frames, the VideoCaptureDevice's reservation on the output buffer | 182 // frame width and height of the buffer contents; this is assumed to be of |
163 // ends immediately. The VideoCaptureDevice may not read or write the | 183 // |format| format and tightly packed. |
164 // underlying memory afterwards, and it should release its references to | 184 virtual void OnIncomingCapturedBuffer(const scoped_refptr<Buffer>& buffer, |
165 // |frame| as soon as possible, to allow buffer reuse. | 185 media::VideoFrame::Format format, |
166 // | 186 const gfx::Size& dimensions, |
167 // If |frame| was NOT created via ReserveOutputBuffer(), then this method | 187 base::Time timestamp, |
168 // will try to reserve an output buffer and copy from |frame| into the | 188 int frame_rate) = 0; |
169 // output buffer. If no output buffer is available, the frame will be | |
170 // silently dropped. |frame| must be allocated as RGB32, YV12 or I420, and | |
171 // the size must match that specified by an earlier call to OnFrameInfo(). | |
172 virtual void OnIncomingCapturedVideoFrame( | |
173 const scoped_refptr<media::VideoFrame>& frame, | |
174 base::Time timestamp, | |
175 int frame_rate) = 0; | |
176 | 189 |
177 // An error has occurred that cannot be handled and VideoCaptureDevice must | 190 // An error has occurred that cannot be handled and VideoCaptureDevice must |
178 // be StopAndDeAllocate()-ed. | 191 // be StopAndDeAllocate()-ed. |
179 virtual void OnError() = 0; | 192 virtual void OnError() = 0; |
180 }; | 193 }; |
181 | 194 |
182 // Creates a VideoCaptureDevice object. | 195 // Creates a VideoCaptureDevice object. |
183 // Return NULL if the hardware is not available. | 196 // Return NULL if the hardware is not available. |
184 static VideoCaptureDevice* Create(const Name& device_name); | 197 static VideoCaptureDevice* Create(const Name& device_name); |
185 virtual ~VideoCaptureDevice(); | 198 virtual ~VideoCaptureDevice(); |
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212 // If deallocation is done asynchronously, then the device implementation must | 225 // If deallocation is done asynchronously, then the device implementation must |
213 // ensure that a subsequent AllocateAndStart() operation targeting the same ID | 226 // ensure that a subsequent AllocateAndStart() operation targeting the same ID |
214 // would be sequenced through the same task runner, so that deallocation | 227 // would be sequenced through the same task runner, so that deallocation |
215 // happens first. | 228 // happens first. |
216 virtual void StopAndDeAllocate() = 0; | 229 virtual void StopAndDeAllocate() = 0; |
217 }; | 230 }; |
218 | 231 |
219 } // namespace media | 232 } // namespace media |
220 | 233 |
221 #endif // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ | 234 #endif // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_ |
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