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19 #ifndef AVDEVICE_AVDEVICE_H
20 #define AVDEVICE_AVDEVICE_H
27 * Main libavdevice API header
31 * @defgroup lavd libavdevice
32 * Special devices muxing/demuxing library.
34 * Libavdevice is a complementary library to @ref libavf "libavformat". It
35 * provides various "special" platform-specific muxers and demuxers, e.g. for
36 * grabbing devices, audio capture and playback etc. As a consequence, the
37 * (de)muxers in libavdevice are of the AVFMT_NOFILE type (they use their own
38 * I/O functions). The filename passed to avformat_open_input() often does not
39 * refer to an actually existing file, but has some special device-specific
40 * meaning - e.g. for xcbgrab it is the display name.
42 * To use libavdevice, simply call avdevice_register_all() to register all
43 * compiled muxers and demuxers. They all use standard libavformat API.
48 #include "libavutil/log.h"
49 #include "libavutil/opt.h"
50 #include "libavutil/dict.h"
51 #include "libavformat/avformat.h"
54 * Return the LIBAVDEVICE_VERSION_INT constant.
56 unsigned avdevice_version(void);
59 * Return the libavdevice build-time configuration.
61 const char *avdevice_configuration(void);
64 * Return the libavdevice license.
66 const char *avdevice_license(void);
69 * Iterate over all registered output devices.
71 * @param opaque a pointer where libavdevice will store the iteration state. Must
72 * point to NULL to start the iteration.
74 * @return the next registered output device or NULL when the iteration is
77 const AVOutputFormat *av_outdev_iterate(void **opaque);
80 * Iterate over all registered input devices.
82 * @param opaque a pointer where libavdevice will store the iteration state. Must
83 * point to NULL to start the iteration.
85 * @return the next registered input device or NULL when the iteration is
88 const AVInputFormat *av_indev_iterate(void **opaque);
92 * Initialize libavdevice and register all the input and output devices.
94 void avdevice_register_all(void);
97 * Audio input devices iterator.
99 * If d is NULL, returns the first registered input audio/video device,
100 * if d is non-NULL, returns the next registered input audio/video device after d
101 * or NULL if d is the last one.
104 AVInputFormat *av_input_audio_device_next(AVInputFormat *d);
107 * Video input devices iterator.
109 * If d is NULL, returns the first registered input audio/video device,
110 * if d is non-NULL, returns the next registered input audio/video device after d
111 * or NULL if d is the last one.
114 AVInputFormat *av_input_video_device_next(AVInputFormat *d);
117 * Audio output devices iterator.
119 * If d is NULL, returns the first registered output audio/video device,
120 * if d is non-NULL, returns the next registered output audio/video device after d
121 * or NULL if d is the last one.
124 AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d);
127 * Video output devices iterator.
129 * If d is NULL, returns the first registered output audio/video device,
130 * if d is non-NULL, returns the next registered output audio/video device after d
131 * or NULL if d is the last one.
134 AVOutputFormat *av_output_video_device_next(AVOutputFormat *d);
137 typedef struct AVDeviceRect {
138 int x; /**< x coordinate of top left corner */
139 int y; /**< y coordinate of top left corner */
140 int width; /**< width */
141 int height; /**< height */
145 * Message types used by avdevice_app_to_dev_control_message().
147 enum AVAppToDevMessageType {
151 AV_APP_TO_DEV_NONE = MKBETAG('N','O','N','E'),
154 * Window size change message.
156 * Message is sent to the device every time the application changes the size
157 * of the window device renders to.
158 * Message should also be sent right after window is created.
160 * data: AVDeviceRect: new window size.
162 AV_APP_TO_DEV_WINDOW_SIZE = MKBETAG('G','E','O','M'),
165 * Repaint request message.
167 * Message is sent to the device when window has to be repainted.
169 * data: AVDeviceRect: area required to be repainted.
170 * NULL: whole area is required to be repainted.
172 AV_APP_TO_DEV_WINDOW_REPAINT = MKBETAG('R','E','P','A'),
175 * Request pause/play.
177 * Application requests pause/unpause playback.
178 * Mostly usable with devices that have internal buffer.
179 * By default devices are not paused.
183 AV_APP_TO_DEV_PAUSE = MKBETAG('P', 'A', 'U', ' '),
184 AV_APP_TO_DEV_PLAY = MKBETAG('P', 'L', 'A', 'Y'),
185 AV_APP_TO_DEV_TOGGLE_PAUSE = MKBETAG('P', 'A', 'U', 'T'),
188 * Volume control message.
190 * Set volume level. It may be device-dependent if volume
191 * is changed per stream or system wide. Per stream volume
192 * change is expected when possible.
194 * data: double: new volume with range of 0.0 - 1.0.
196 AV_APP_TO_DEV_SET_VOLUME = MKBETAG('S', 'V', 'O', 'L'),
199 * Mute control messages.
201 * Change mute state. It may be device-dependent if mute status
202 * is changed per stream or system wide. Per stream mute status
203 * change is expected when possible.
207 AV_APP_TO_DEV_MUTE = MKBETAG(' ', 'M', 'U', 'T'),
208 AV_APP_TO_DEV_UNMUTE = MKBETAG('U', 'M', 'U', 'T'),
209 AV_APP_TO_DEV_TOGGLE_MUTE = MKBETAG('T', 'M', 'U', 'T'),
212 * Get volume/mute messages.
214 * Force the device to send AV_DEV_TO_APP_VOLUME_LEVEL_CHANGED or
215 * AV_DEV_TO_APP_MUTE_STATE_CHANGED command respectively.
219 AV_APP_TO_DEV_GET_VOLUME = MKBETAG('G', 'V', 'O', 'L'),
220 AV_APP_TO_DEV_GET_MUTE = MKBETAG('G', 'M', 'U', 'T'),
224 * Message types used by avdevice_dev_to_app_control_message().
226 enum AVDevToAppMessageType {
230 AV_DEV_TO_APP_NONE = MKBETAG('N','O','N','E'),
233 * Create window buffer message.
235 * Device requests to create a window buffer. Exact meaning is device-
236 * and application-dependent. Message is sent before rendering first
237 * frame and all one-shot initializations should be done here.
238 * Application is allowed to ignore preferred window buffer size.
240 * @note: Application is obligated to inform about window buffer size
241 * with AV_APP_TO_DEV_WINDOW_SIZE message.
243 * data: AVDeviceRect: preferred size of the window buffer.
244 * NULL: no preferred size of the window buffer.
246 AV_DEV_TO_APP_CREATE_WINDOW_BUFFER = MKBETAG('B','C','R','E'),
249 * Prepare window buffer message.
251 * Device requests to prepare a window buffer for rendering.
252 * Exact meaning is device- and application-dependent.
253 * Message is sent before rendering of each frame.
257 AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER = MKBETAG('B','P','R','E'),
260 * Display window buffer message.
262 * Device requests to display a window buffer.
263 * Message is sent when new frame is ready to be displayed.
264 * Usually buffers need to be swapped in handler of this message.
268 AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER = MKBETAG('B','D','I','S'),
271 * Destroy window buffer message.
273 * Device requests to destroy a window buffer.
274 * Message is sent when device is about to be destroyed and window
275 * buffer is not required anymore.
279 AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER = MKBETAG('B','D','E','S'),
282 * Buffer fullness status messages.
284 * Device signals buffer overflow/underflow.
288 AV_DEV_TO_APP_BUFFER_OVERFLOW = MKBETAG('B','O','F','L'),
289 AV_DEV_TO_APP_BUFFER_UNDERFLOW = MKBETAG('B','U','F','L'),
292 * Buffer readable/writable.
294 * Device informs that buffer is readable/writable.
295 * When possible, device informs how many bytes can be read/write.
297 * @warning Device may not inform when number of bytes than can be read/write changes.
299 * data: int64_t: amount of bytes available to read/write.
300 * NULL: amount of bytes available to read/write is not known.
302 AV_DEV_TO_APP_BUFFER_READABLE = MKBETAG('B','R','D',' '),
303 AV_DEV_TO_APP_BUFFER_WRITABLE = MKBETAG('B','W','R',' '),
306 * Mute state change message.
308 * Device informs that mute state has changed.
310 * data: int: 0 for not muted state, non-zero for muted state.
312 AV_DEV_TO_APP_MUTE_STATE_CHANGED = MKBETAG('C','M','U','T'),
315 * Volume level change message.
317 * Device informs that volume level has changed.
319 * data: double: new volume with range of 0.0 - 1.0.
321 AV_DEV_TO_APP_VOLUME_LEVEL_CHANGED = MKBETAG('C','V','O','L'),
325 * Send control message from application to device.
327 * @param s device context.
328 * @param type message type.
329 * @param data message data. Exact type depends on message type.
330 * @param data_size size of message data.
331 * @return >= 0 on success, negative on error.
332 * AVERROR(ENOSYS) when device doesn't implement handler of the message.
334 int avdevice_app_to_dev_control_message(struct AVFormatContext *s,
335 enum AVAppToDevMessageType type,
336 void *data, size_t data_size);
339 * Send control message from device to application.
341 * @param s device context.
342 * @param type message type.
343 * @param data message data. Can be NULL.
344 * @param data_size size of message data.
345 * @return >= 0 on success, negative on error.
346 * AVERROR(ENOSYS) when application doesn't implement handler of the message.
348 int avdevice_dev_to_app_control_message(struct AVFormatContext *s,
349 enum AVDevToAppMessageType type,
350 void *data, size_t data_size);
353 * Following API allows user to probe device capabilities (supported codecs,
354 * pixel formats, sample formats, resolutions, channel counts, etc).
355 * It is build on top op AVOption API.
356 * Queried capabilities make it possible to set up converters of video or audio
357 * parameters that fit to the device.
359 * List of capabilities that can be queried:
360 * - Capabilities valid for both audio and video devices:
361 * - codec: supported audio/video codecs.
362 * type: AV_OPT_TYPE_INT (AVCodecID value)
363 * - Capabilities valid for audio devices:
364 * - sample_format: supported sample formats.
365 * type: AV_OPT_TYPE_INT (AVSampleFormat value)
366 * - sample_rate: supported sample rates.
367 * type: AV_OPT_TYPE_INT
368 * - channels: supported number of channels.
369 * type: AV_OPT_TYPE_INT
370 * - channel_layout: supported channel layouts.
371 * type: AV_OPT_TYPE_INT64
372 * - Capabilities valid for video devices:
373 * - pixel_format: supported pixel formats.
374 * type: AV_OPT_TYPE_INT (AVPixelFormat value)
375 * - window_size: supported window sizes (describes size of the window size presented to the user).
376 * type: AV_OPT_TYPE_IMAGE_SIZE
377 * - frame_size: supported frame sizes (describes size of provided video frames).
378 * type: AV_OPT_TYPE_IMAGE_SIZE
379 * - fps: supported fps values
380 * type: AV_OPT_TYPE_RATIONAL
382 * Value of the capability may be set by user using av_opt_set() function
383 * and AVDeviceCapabilitiesQuery object. Following queries will
384 * limit results to the values matching already set capabilities.
385 * For example, setting a codec may impact number of formats or fps values
386 * returned during next query. Setting invalid value may limit results to zero.
388 * Example of the usage basing on opengl output device:
391 * AVFormatContext *oc = NULL;
392 * AVDeviceCapabilitiesQuery *caps = NULL;
393 * AVOptionRanges *ranges;
396 * if ((ret = avformat_alloc_output_context2(&oc, NULL, "opengl", NULL)) < 0)
398 * if (avdevice_capabilities_create(&caps, oc, NULL) < 0)
402 * if (av_opt_query_ranges(&ranges, caps, "codec", AV_OPT_MULTI_COMPONENT_RANGE)) < 0)
404 * //pick codec here and set it
405 * av_opt_set(caps, "codec", AV_CODEC_ID_RAWVIDEO, 0);
408 * if (av_opt_query_ranges(&ranges, caps, "pixel_format", AV_OPT_MULTI_COMPONENT_RANGE)) < 0)
410 * //pick format here and set it
411 * av_opt_set(caps, "pixel_format", AV_PIX_FMT_YUV420P, 0);
413 * //query and set more capabilities
417 * avdevice_capabilities_free(&query, oc);
418 * avformat_free_context(oc);
423 * Structure describes device capabilities.
425 * It is used by devices in conjunction with av_device_capabilities AVOption table
426 * to implement capabilities probing API based on AVOption API. Should not be used directly.
428 typedef struct AVDeviceCapabilitiesQuery {
429 const AVClass *av_class;
430 AVFormatContext *device_context;
431 enum AVCodecID codec;
432 enum AVSampleFormat sample_format;
433 enum AVPixelFormat pixel_format;
436 int64_t channel_layout;
442 } AVDeviceCapabilitiesQuery;
445 * AVOption table used by devices to implement device capabilities API. Should not be used by a user.
447 extern const AVOption av_device_capabilities[];
450 * Initialize capabilities probing API based on AVOption API.
452 * avdevice_capabilities_free() must be called when query capabilities API is
455 * @param[out] caps Device capabilities data. Pointer to a NULL pointer must be passed.
456 * @param s Context of the device.
457 * @param device_options An AVDictionary filled with device-private options.
458 * On return this parameter will be destroyed and replaced with a dict
459 * containing options that were not found. May be NULL.
460 * The same options must be passed later to avformat_write_header() for output
461 * devices or avformat_open_input() for input devices, or at any other place
462 * that affects device-private options.
464 * @return >= 0 on success, negative otherwise.
466 int avdevice_capabilities_create(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s,
467 AVDictionary **device_options);
470 * Free resources created by avdevice_capabilities_create()
472 * @param caps Device capabilities data to be freed.
473 * @param s Context of the device.
475 void avdevice_capabilities_free(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s);
478 * Structure describes basic parameters of the device.
480 typedef struct AVDeviceInfo {
481 char *device_name; /**< device name, format depends on device */
482 char *device_description; /**< human friendly name */
488 typedef struct AVDeviceInfoList {
489 AVDeviceInfo **devices; /**< list of autodetected devices */
490 int nb_devices; /**< number of autodetected devices */
491 int default_device; /**< index of default device or -1 if no default */
497 * Returns available device names and their parameters.
499 * @note: Some devices may accept system-dependent device names that cannot be
500 * autodetected. The list returned by this function cannot be assumed to
501 * be always completed.
503 * @param s device context.
504 * @param[out] device_list list of autodetected devices.
505 * @return count of autodetected devices, negative on error.
507 int avdevice_list_devices(struct AVFormatContext *s, AVDeviceInfoList **device_list);
510 * Convenient function to free result of avdevice_list_devices().
512 * @param devices device list to be freed.
514 void avdevice_free_list_devices(AVDeviceInfoList **device_list);
519 * Returns available device names and their parameters.
520 * These are convinient wrappers for avdevice_list_devices().
521 * Device context is allocated and deallocated internally.
523 * @param device device format. May be NULL if device name is set.
524 * @param device_name device name. May be NULL if device format is set.
525 * @param device_options An AVDictionary filled with device-private options. May be NULL.
526 * The same options must be passed later to avformat_write_header() for output
527 * devices or avformat_open_input() for input devices, or at any other place
528 * that affects device-private options.
529 * @param[out] device_list list of autodetected devices
530 * @return count of autodetected devices, negative on error.
531 * @note device argument takes precedence over device_name when both are set.
533 int avdevice_list_input_sources(struct AVInputFormat *device, const char *device_name,
534 AVDictionary *device_options, AVDeviceInfoList **device_list);
535 int avdevice_list_output_sinks(struct AVOutputFormat *device, const char *device_name,
536 AVDictionary *device_options, AVDeviceInfoList **device_list);
542 #endif /* AVDEVICE_AVDEVICE_H */