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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 "libavutil/log.h"
47 #include "libavutil/opt.h"
48 #include "libavutil/dict.h"
49 #include "libavformat/avformat.h"
50 
51 /**
52  * Return the LIBAVDEVICE_VERSION_INT constant.
53  */
54 unsigned avdevice_version(void);
55 
56 /**
57  * Return the libavdevice build-time configuration.
58  */
59 const char *avdevice_configuration(void);
60 
61 /**
62  * Return the libavdevice license.
63  */
64 const char *avdevice_license(void);
65 
66 /**
67  * Initialize libavdevice and register all the input and output devices.
68  * @warning This function is not thread safe.
69  */
70 void avdevice_register_all(void);
71 
72 /**
73  * Audio input devices iterator.
74  *
75  * If d is NULL, returns the first registered input audio/video device,
76  * if d is non-NULL, returns the next registered input audio/video device after d
77  * or NULL if d is the last one.
78  */
80 
81 /**
82  * Video input devices iterator.
83  *
84  * If d is NULL, returns the first registered input audio/video device,
85  * if d is non-NULL, returns the next registered input audio/video device after d
86  * or NULL if d is the last one.
87  */
89 
90 /**
91  * Audio output devices iterator.
92  *
93  * If d is NULL, returns the first registered output audio/video device,
94  * if d is non-NULL, returns the next registered output audio/video device after d
95  * or NULL if d is the last one.
96  */
98 
99 /**
100  * Video output devices iterator.
101  *
102  * If d is NULL, returns the first registered output audio/video device,
103  * if d is non-NULL, returns the next registered output audio/video device after d
104  * or NULL if d is the last one.
105  */
107 
108 typedef struct AVDeviceRect {
109  int x; /**< x coordinate of top left corner */
110  int y; /**< y coordinate of top left corner */
111  int width; /**< width */
112  int height; /**< height */
113 } AVDeviceRect;
114 
115 /**
116  * Message types used by avdevice_app_to_dev_control_message().
117  */
119  /**
120  * Dummy message.
121  */
122  AV_APP_TO_DEV_NONE = MKBETAG('N','O','N','E'),
123 
124  /**
125  * Window size change message.
126  *
127  * Message is sent to the device every time the application changes the size
128  * of the window device renders to.
129  * Message should also be sent right after window is created.
130  *
131  * data: AVDeviceRect: new window size.
132  */
133  AV_APP_TO_DEV_WINDOW_SIZE = MKBETAG('G','E','O','M'),
134 
135  /**
136  * Repaint request message.
137  *
138  * Message is sent to the device when window has to be repainted.
139  *
140  * data: AVDeviceRect: area required to be repainted.
141  * NULL: whole area is required to be repainted.
142  */
144 
145  /**
146  * Request pause/play.
147  *
148  * Application requests pause/unpause playback.
149  * Mostly usable with devices that have internal buffer.
150  * By default devices are not paused.
151  *
152  * data: NULL
153  */
154  AV_APP_TO_DEV_PAUSE = MKBETAG('P', 'A', 'U', ' '),
155  AV_APP_TO_DEV_PLAY = MKBETAG('P', 'L', 'A', 'Y'),
156  AV_APP_TO_DEV_TOGGLE_PAUSE = MKBETAG('P', 'A', 'U', 'T'),
157 
158  /**
159  * Volume control message.
160  *
161  * Set volume level. It may be device-dependent if volume
162  * is changed per stream or system wide. Per stream volume
163  * change is expected when possible.
164  *
165  * data: double: new volume with range of 0.0 - 1.0.
166  */
167  AV_APP_TO_DEV_SET_VOLUME = MKBETAG('S', 'V', 'O', 'L'),
168 
169  /**
170  * Mute control messages.
171  *
172  * Change mute state. It may be device-dependent if mute status
173  * is changed per stream or system wide. Per stream mute status
174  * change is expected when possible.
175  *
176  * data: NULL.
177  */
178  AV_APP_TO_DEV_MUTE = MKBETAG(' ', 'M', 'U', 'T'),
179  AV_APP_TO_DEV_UNMUTE = MKBETAG('U', 'M', 'U', 'T'),
180  AV_APP_TO_DEV_TOGGLE_MUTE = MKBETAG('T', 'M', 'U', 'T'),
181 
182  /**
183  * Get volume/mute messages.
184  *
185  * Force the device to send AV_DEV_TO_APP_VOLUME_LEVEL_CHANGED or
186  * AV_DEV_TO_APP_MUTE_STATE_CHANGED command respectively.
187  *
188  * data: NULL.
189  */
190  AV_APP_TO_DEV_GET_VOLUME = MKBETAG('G', 'V', 'O', 'L'),
191  AV_APP_TO_DEV_GET_MUTE = MKBETAG('G', 'M', 'U', 'T'),
192 };
193 
194 /**
195  * Message types used by avdevice_dev_to_app_control_message().
196  */
198  /**
199  * Dummy message.
200  */
201  AV_DEV_TO_APP_NONE = MKBETAG('N','O','N','E'),
202 
203  /**
204  * Create window buffer message.
205  *
206  * Device requests to create a window buffer. Exact meaning is device-
207  * and application-dependent. Message is sent before rendering first
208  * frame and all one-shot initializations should be done here.
209  * Application is allowed to ignore preferred window buffer size.
210  *
211  * @note: Application is obligated to inform about window buffer size
212  * with AV_APP_TO_DEV_WINDOW_SIZE message.
213  *
214  * data: AVDeviceRect: preferred size of the window buffer.
215  * NULL: no preferred size of the window buffer.
216  */
218 
219  /**
220  * Prepare window buffer message.
221  *
222  * Device requests to prepare a window buffer for rendering.
223  * Exact meaning is device- and application-dependent.
224  * Message is sent before rendering of each frame.
225  *
226  * data: NULL.
227  */
229 
230  /**
231  * Display window buffer message.
232  *
233  * Device requests to display a window buffer.
234  * Message is sent when new frame is ready to be displayed.
235  * Usually buffers need to be swapped in handler of this message.
236  *
237  * data: NULL.
238  */
240 
241  /**
242  * Destroy window buffer message.
243  *
244  * Device requests to destroy a window buffer.
245  * Message is sent when device is about to be destroyed and window
246  * buffer is not required anymore.
247  *
248  * data: NULL.
249  */
251 
252  /**
253  * Buffer fullness status messages.
254  *
255  * Device signals buffer overflow/underflow.
256  *
257  * data: NULL.
258  */
261 
262  /**
263  * Buffer readable/writable.
264  *
265  * Device informs that buffer is readable/writable.
266  * When possible, device informs how many bytes can be read/write.
267  *
268  * @warning Device may not inform when number of bytes than can be read/write changes.
269  *
270  * data: int64_t: amount of bytes available to read/write.
271  * NULL: amount of bytes available to read/write is not known.
272  */
275 
276  /**
277  * Mute state change message.
278  *
279  * Device informs that mute state has changed.
280  *
281  * data: int: 0 for not muted state, non-zero for muted state.
282  */
284 
285  /**
286  * Volume level change message.
287  *
288  * Device informs that volume level has changed.
289  *
290  * data: double: new volume with range of 0.0 - 1.0.
291  */
293 };
294 
295 /**
296  * Send control message from application to device.
297  *
298  * @param s device context.
299  * @param type message type.
300  * @param data message data. Exact type depends on message type.
301  * @param data_size size of message data.
302  * @return >= 0 on success, negative on error.
303  * AVERROR(ENOSYS) when device doesn't implement handler of the message.
304  */
307  void *data, size_t data_size);
308 
309 /**
310  * Send control message from device to application.
311  *
312  * @param s device context.
313  * @param type message type.
314  * @param data message data. Can be NULL.
315  * @param data_size size of message data.
316  * @return >= 0 on success, negative on error.
317  * AVERROR(ENOSYS) when application doesn't implement handler of the message.
318  */
321  void *data, size_t data_size);
322 
323 /**
324  * Following API allows user to probe device capabilities (supported codecs,
325  * pixel formats, sample formats, resolutions, channel counts, etc).
326  * It is build on top op AVOption API.
327  * Queried capabilities make it possible to set up converters of video or audio
328  * parameters that fit to the device.
329  *
330  * List of capabilities that can be queried:
331  * - Capabilities valid for both audio and video devices:
332  * - codec: supported audio/video codecs.
333  * type: AV_OPT_TYPE_INT (AVCodecID value)
334  * - Capabilities valid for audio devices:
335  * - sample_format: supported sample formats.
336  * type: AV_OPT_TYPE_INT (AVSampleFormat value)
337  * - sample_rate: supported sample rates.
338  * type: AV_OPT_TYPE_INT
339  * - channels: supported number of channels.
340  * type: AV_OPT_TYPE_INT
341  * - channel_layout: supported channel layouts.
342  * type: AV_OPT_TYPE_INT64
343  * - Capabilities valid for video devices:
344  * - pixel_format: supported pixel formats.
345  * type: AV_OPT_TYPE_INT (AVPixelFormat value)
346  * - window_size: supported window sizes (describes size of the window size presented to the user).
347  * type: AV_OPT_TYPE_IMAGE_SIZE
348  * - frame_size: supported frame sizes (describes size of provided video frames).
349  * type: AV_OPT_TYPE_IMAGE_SIZE
350  * - fps: supported fps values
351  * type: AV_OPT_TYPE_RATIONAL
352  *
353  * Value of the capability may be set by user using av_opt_set() function
354  * and AVDeviceCapabilitiesQuery object. Following queries will
355  * limit results to the values matching already set capabilities.
356  * For example, setting a codec may impact number of formats or fps values
357  * returned during next query. Setting invalid value may limit results to zero.
358  *
359  * Example of the usage basing on opengl output device:
360  *
361  * @code
362  * AVFormatContext *oc = NULL;
363  * AVDeviceCapabilitiesQuery *caps = NULL;
364  * AVOptionRanges *ranges;
365  * int ret;
366  *
367  * if ((ret = avformat_alloc_output_context2(&oc, NULL, "opengl", NULL)) < 0)
368  * goto fail;
369  * if (avdevice_capabilities_create(&caps, oc, NULL) < 0)
370  * goto fail;
371  *
372  * //query codecs
373  * if (av_opt_query_ranges(&ranges, caps, "codec", AV_OPT_MULTI_COMPONENT_RANGE)) < 0)
374  * goto fail;
375  * //pick codec here and set it
376  * av_opt_set(caps, "codec", AV_CODEC_ID_RAWVIDEO, 0);
377  *
378  * //query format
379  * if (av_opt_query_ranges(&ranges, caps, "pixel_format", AV_OPT_MULTI_COMPONENT_RANGE)) < 0)
380  * goto fail;
381  * //pick format here and set it
382  * av_opt_set(caps, "pixel_format", AV_PIX_FMT_YUV420P, 0);
383  *
384  * //query and set more capabilities
385  *
386  * fail:
387  * //clean up code
388  * avdevice_capabilities_free(&query, oc);
389  * avformat_free_context(oc);
390  * @endcode
391  */
392 
393 /**
394  * Structure describes device capabilities.
395  *
396  * It is used by devices in conjunction with av_device_capabilities AVOption table
397  * to implement capabilities probing API based on AVOption API. Should not be used directly.
398  */
406  int channels;
407  int64_t channel_layout;
414 
415 /**
416  * AVOption table used by devices to implement device capabilities API. Should not be used by a user.
417  */
418 extern const AVOption av_device_capabilities[];
419 
420 /**
421  * Initialize capabilities probing API based on AVOption API.
422  *
423  * avdevice_capabilities_free() must be called when query capabilities API is
424  * not used anymore.
425  *
426  * @param[out] caps Device capabilities data. Pointer to a NULL pointer must be passed.
427  * @param s Context of the device.
428  * @param device_options An AVDictionary filled with device-private options.
429  * On return this parameter will be destroyed and replaced with a dict
430  * containing options that were not found. May be NULL.
431  * The same options must be passed later to avformat_write_header() for output
432  * devices or avformat_open_input() for input devices, or at any other place
433  * that affects device-private options.
434  *
435  * @return >= 0 on success, negative otherwise.
436  */
438  AVDictionary **device_options);
439 
440 /**
441  * Free resources created by avdevice_capabilities_create()
442  *
443  * @param caps Device capabilities data to be freed.
444  * @param s Context of the device.
445  */
447 
448 /**
449  * Structure describes basic parameters of the device.
450  */
451 typedef struct AVDeviceInfo {
452  char *device_name; /**< device name, format depends on device */
453  char *device_description; /**< human friendly name */
454 } AVDeviceInfo;
455 
456 /**
457  * List of devices.
458  */
459 typedef struct AVDeviceInfoList {
460  AVDeviceInfo **devices; /**< list of autodetected devices */
461  int nb_devices; /**< number of autodetected devices */
462  int default_device; /**< index of default device or -1 if no default */
464 
465 /**
466  * List devices.
467  *
468  * Returns available device names and their parameters.
469  *
470  * @note: Some devices may accept system-dependent device names that cannot be
471  * autodetected. The list returned by this function cannot be assumed to
472  * be always completed.
473  *
474  * @param s device context.
475  * @param[out] device_list list of autodetected devices.
476  * @return count of autodetected devices, negative on error.
477  */
478 int avdevice_list_devices(struct AVFormatContext *s, AVDeviceInfoList **device_list);
479 
480 /**
481  * Convenient function to free result of avdevice_list_devices().
482  *
483  * @param devices device list to be freed.
484  */
485 void avdevice_free_list_devices(AVDeviceInfoList **device_list);
486 
487 /**
488  * List devices.
489  *
490  * Returns available device names and their parameters.
491  * These are convinient wrappers for avdevice_list_devices().
492  * Device context is allocated and deallocated internally.
493  *
494  * @param device device format. May be NULL if device name is set.
495  * @param device_name device name. May be NULL if device format is set.
496  * @param device_options An AVDictionary filled with device-private options. May be NULL.
497  * The same options must be passed later to avformat_write_header() for output
498  * devices or avformat_open_input() for input devices, or at any other place
499  * that affects device-private options.
500  * @param[out] device_list list of autodetected devices
501  * @return count of autodetected devices, negative on error.
502  * @note device argument takes precedence over device_name when both are set.
503  */
504 int avdevice_list_input_sources(struct AVInputFormat *device, const char *device_name,
505  AVDictionary *device_options, AVDeviceInfoList **device_list);
506 int avdevice_list_output_sinks(struct AVOutputFormat *device, const char *device_name,
507  AVDictionary *device_options, AVDeviceInfoList **device_list);
508 
509 #endif /* AVDEVICE_AVDEVICE_H */
int avdevice_list_devices(struct AVFormatContext *s, AVDeviceInfoList **device_list)
List devices.
Definition: avdevice.c:187
Structure describes basic parameters of the device.
Definition: avdevice.h:451
const char * s
Definition: avisynth_c.h:631
int x
x coordinate of top left corner
Definition: avdevice.h:109
AVOption.
Definition: opt.h:245
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
AVInputFormat * av_input_audio_device_next(AVInputFormat *d)
Audio input devices iterator.
Definition: avdevice.c:103
char * device_description
human friendly name
Definition: avdevice.h:453
const char * avdevice_configuration(void)
Return the libavdevice build-time configuration.
Definition: avdevice.c:70
const char * avdevice_license(void)
Return the libavdevice license.
Definition: avdevice.c:75
char * device_name
device name, format depends on device
Definition: avdevice.h:452
Destroy window buffer message.
Definition: avdevice.h:250
Repaint request message.
Definition: avdevice.h:143
AVOutputFormat * av_output_audio_device_next(AVOutputFormat *d)
Audio output devices iterator.
Definition: avdevice.c:115
unsigned avdevice_version(void)
Return the LIBAVDEVICE_VERSION_INT constant.
Definition: avdevice.c:64
Window size change message.
Definition: avdevice.h:133
Format I/O context.
Definition: avformat.h:1319
Public dictionary API.
void avdevice_free_list_devices(AVDeviceInfoList **device_list)
Convenient function to free result of avdevice_list_devices().
Definition: avdevice.c:250
AVOptions.
int avdevice_dev_to_app_control_message(struct AVFormatContext *s, enum AVDevToAppMessageType type, void *data, size_t data_size)
Send control message from device to application.
Definition: avdevice.c:135
int avdevice_capabilities_create(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s, AVDictionary **device_options)
Initialize capabilities probing API based on AVOption API.
Definition: avdevice.c:143
Buffer readable/writable.
Definition: avdevice.h:273
AVDevToAppMessageType
Message types used by avdevice_dev_to_app_control_message().
Definition: avdevice.h:197
Prepare window buffer message.
Definition: avdevice.h:228
const AVClass * av_class
Definition: avdevice.h:400
Create window buffer message.
Definition: avdevice.h:217
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:189
enum AVSampleFormat sample_format
Definition: avdevice.h:403
Dummy message.
Definition: avdevice.h:201
int avdevice_app_to_dev_control_message(struct AVFormatContext *s, enum AVAppToDevMessageType type, void *data, size_t data_size)
Send control message from application to device.
Definition: avdevice.c:127
AVDeviceInfo ** devices
list of autodetected devices
Definition: avdevice.h:460
AVAppToDevMessageType
Message types used by avdevice_app_to_dev_control_message().
Definition: avdevice.h:118
AVFormatContext * device_context
Definition: avdevice.h:401
Mute control messages.
Definition: avdevice.h:178
const AVOption av_device_capabilities[]
AVOption table used by devices to implement device capabilities API.
Definition: avdevice.c:36
Volume control message.
Definition: avdevice.h:167
Volume level change message.
Definition: avdevice.h:292
int avdevice_list_input_sources(struct AVInputFormat *device, const char *device_name, AVDictionary *device_options, AVDeviceInfoList **device_list)
List devices.
Definition: avdevice.c:228
Request pause/play.
Definition: avdevice.h:154
enum AVPixelFormat pixel_format
Definition: avdevice.h:404
Mute state change message.
Definition: avdevice.h:283
enum AVCodecID codec
Definition: avdevice.h:402
int height
height
Definition: avdevice.h:112
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
void avdevice_register_all(void)
Initialize libavdevice and register all the input and output devices.
Definition: alldevices.c:40
Buffer fullness status messages.
Definition: avdevice.h:259
GLint GLenum type
Definition: opengl_enc.c:105
Describe the class of an AVClass context structure.
Definition: log.h:67
rational number numerator/denominator
Definition: rational.h:43
AVInputFormat * av_input_video_device_next(AVInputFormat *d)
Video input devices iterator.
Definition: avdevice.c:109
int default_device
index of default device or -1 if no default
Definition: avdevice.h:462
List of devices.
Definition: avdevice.h:459
Libavdevice version macros.
int width
width
Definition: avdevice.h:111
void avdevice_capabilities_free(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s)
Free resources created by avdevice_capabilities_create()
Definition: avdevice.c:172
Main libavformat public API header.
AVOutputFormat * av_output_video_device_next(AVOutputFormat *d)
Video output devices iterator.
Definition: avdevice.c:121
#define MKBETAG(a, b, c, d)
Definition: common.h:343
int avdevice_list_output_sinks(struct AVOutputFormat *device, const char *device_name, AVDictionary *device_options, AVDeviceInfoList **device_list)
Definition: avdevice.c:239
int y
y coordinate of top left corner
Definition: avdevice.h:110
Get volume/mute messages.
Definition: avdevice.h:190
Dummy message.
Definition: avdevice.h:122
int nb_devices
number of autodetected devices
Definition: avdevice.h:461
Following API allows user to probe device capabilities (supported codecs, pixel formats, sample formats, resolutions, channel counts, etc).
Definition: avdevice.h:399
AVPixelFormat
Pixel format.
Definition: pixfmt.h:60
Display window buffer message.
Definition: avdevice.h:239