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avdevice.h
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18 
19 #ifndef AVDEVICE_AVDEVICE_H
20 #define AVDEVICE_AVDEVICE_H
21 
22 #include "version.h"
23 
24 /**
25  * @file
26  * @ingroup lavd
27  * Main libavdevice API header
28  */
29 
30 /**
31  * @defgroup lavd Special devices muxing/demuxing library
32  * @{
33  * Libavdevice is a complementary library to @ref libavf "libavformat". It
34  * provides various "special" platform-specific muxers and demuxers, e.g. for
35  * grabbing devices, audio capture and playback etc. As a consequence, the
36  * (de)muxers in libavdevice are of the AVFMT_NOFILE type (they use their own
37  * I/O functions). The filename passed to avformat_open_input() often does not
38  * refer to an actually existing file, but has some special device-specific
39  * meaning - e.g. for x11grab it is the display name.
40  *
41  * To use libavdevice, simply call avdevice_register_all() to register all
42  * compiled muxers and demuxers. They all use standard libavformat API.
43  * @}
44  */
45 
46 #include "libavformat/avformat.h"
47 
48 /**
49  * Return the LIBAVDEVICE_VERSION_INT constant.
50  */
51 unsigned avdevice_version(void);
52 
53 /**
54  * Return the libavdevice build-time configuration.
55  */
56 const char *avdevice_configuration(void);
57 
58 /**
59  * Return the libavdevice license.
60  */
61 const char *avdevice_license(void);
62 
63 /**
64  * Initialize libavdevice and register all the input and output devices.
65  * @warning This function is not thread safe.
66  */
67 void avdevice_register_all(void);
68 
69 typedef struct AVDeviceRect {
70  int x; /**< x coordinate of top left corner */
71  int y; /**< y coordinate of top left corner */
72  int width; /**< width */
73  int height; /**< height */
74 } AVDeviceRect;
75 
76 /**
77  * Message types used by avdevice_app_to_dev_control_message().
78  */
80  /**
81  * Dummy message.
82  */
83  AV_APP_TO_DEV_NONE = MKBETAG('N','O','N','E'),
84 
85  /**
86  * Window size change message.
87  *
88  * Message is sent to the device every time the application changes the size
89  * of the window device renders to.
90  * Message should also be sent right after window is created.
91  *
92  * data: AVDeviceRect: new window size.
93  */
94  AV_APP_TO_DEV_WINDOW_SIZE = MKBETAG('G','E','O','M'),
95 
96  /**
97  * Repaint request message.
98  *
99  * Message is sent to the device when window have to be rapainted.
100  *
101  * data: AVDeviceRect: area required to be repainted.
102  * NULL: whole area is required to be repainted.
103  */
105 };
106 
107 /**
108  * Message types used by avdevice_dev_to_app_control_message().
109  */
111  /**
112  * Dummy message.
113  */
114  AV_DEV_TO_APP_NONE = MKBETAG('N','O','N','E'),
115 
116  /**
117  * Create window buffer message.
118  *
119  * Device requests to create a window buffer. Exact meaning is device-
120  * and application-dependent. Message is sent before rendering first
121  * frame and all one-shot initializations should be done here.
122  * Application is allowed to ignore preferred window buffer size.
123  *
124  * @note: Application is obligated to inform about window buffer size
125  * with AV_APP_TO_DEV_WINDOW_SIZE message.
126  *
127  * data: AVDeviceRect: preferred size of the window buffer.
128  * NULL: no preferred size of the window buffer.
129  */
131 
132  /**
133  * Prepare window buffer message.
134  *
135  * Device requests to prepare a window buffer for rendering.
136  * Exact meaning is device- and application-dependent.
137  * Message is sent before rendering of each frame.
138  *
139  * data: NULL.
140  */
142 
143  /**
144  * Display window buffer message.
145  *
146  * Device requests to display a window buffer.
147  * Message is sent when new frame is ready to be displyed.
148  * Usually buffers need to be swapped in handler of this message.
149  *
150  * data: NULL.
151  */
153 
154  /**
155  * Destroy window buffer message.
156  *
157  * Device requests to destroy a window buffer.
158  * Message is sent when device is about to be destroyed and window
159  * buffer is not required anymore.
160  *
161  * data: NULL.
162  */
164 };
165 
166 /**
167  * Send control message from application to device.
168  *
169  * @param s device context.
170  * @param type message type.
171  * @param data message data. Exact type depends on message type.
172  * @param data_size size of message data.
173  * @return >= 0 on success, negative on error.
174  * AVERROR(ENOSYS) when device doesn't implement handler of the message.
175  */
178  void *data, size_t data_size);
179 
180 /**
181  * Send control message from device to application.
182  *
183  * @param s device context.
184  * @param type message type.
185  * @param data message data. Can be NULL.
186  * @param data_size size of message data.
187  * @return >= 0 on success, negative on error.
188  * AVERROR(ENOSYS) when application doesn't implement handler of the message.
189  */
192  void *data, size_t data_size);
193 
194 /**
195  * Structure describes basic parameters of the device.
196  */
197 typedef struct AVDeviceInfo {
198  char *device_name; /**< device name, format depends on device */
199  char *device_description; /**< human friendly name */
200 } AVDeviceInfo;
201 
202 /**
203  * List of devices.
204  */
205 typedef struct AVDeviceInfoList {
206  AVDeviceInfo **devices; /**< list of autodetected devices */
207  int nb_devices; /**< number of autodetected devices */
208  int default_device; /**< index of default device or -1 if no default */
210 
211 /**
212  * List devices.
213  *
214  * Returns available device names and their parameters.
215  *
216  * @note: Some devices may accept system-dependent device names that cannot be
217  * autodetected. The list returned by this function cannot be assumed to
218  * be always completed.
219  *
220  * @param s device context.
221  * @param[out] device_list list of autodetected devices.
222  * @return count of autodetected devices, negative on error.
223  */
224 int avdevice_list_devices(struct AVFormatContext *s, AVDeviceInfoList **device_list);
225 
226 /**
227  * Convinient function to free result of avdevice_list_devices().
228  *
229  * @param devices device list to be freed.
230  */
231 void avdevice_free_list_devices(AVDeviceInfoList **device_list);
232 
233 #endif /* AVDEVICE_AVDEVICE_H */