ffmpeg/libavdevice/avdevice.h

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  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  */
  79 AVInputFormat *av_input_audio_device_next(AVInputFormat  *d);
  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  */
  88 AVInputFormat *av_input_video_device_next(AVInputFormat  *d);
  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  */
  97 AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d);
  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  */
 106 AVOutputFormat *av_output_video_device_next(AVOutputFormat *d);
 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  */
 118 enum AVAppToDevMessageType {
 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      */
 143     AV_APP_TO_DEV_WINDOW_REPAINT = MKBETAG('R','E','P','A'),
 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  */
 197 enum AVDevToAppMessageType {
 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      */
 217     AV_DEV_TO_APP_CREATE_WINDOW_BUFFER = MKBETAG('B','C','R','E'),
 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      */
 228     AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER = MKBETAG('B','P','R','E'),
 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      */
 239     AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER = MKBETAG('B','D','I','S'),
 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      */
 250     AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER = MKBETAG('B','D','E','S'),
 251
 252     /**
 253      * Buffer fullness status messages.
 254      *
 255      * Device signals buffer overflow/underflow.
 256      *
 257      * data: NULL.
 258      */
 259     AV_DEV_TO_APP_BUFFER_OVERFLOW = MKBETAG('B','O','F','L'),
 260     AV_DEV_TO_APP_BUFFER_UNDERFLOW = MKBETAG('B','U','F','L'),
 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      */
 273     AV_DEV_TO_APP_BUFFER_READABLE = MKBETAG('B','R','D',' '),
 274     AV_DEV_TO_APP_BUFFER_WRITABLE = MKBETAG('B','W','R',' '),
 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      */
 283     AV_DEV_TO_APP_MUTE_STATE_CHANGED = MKBETAG('C','M','U','T'),
 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      */
 292     AV_DEV_TO_APP_VOLUME_LEVEL_CHANGED = MKBETAG('C','V','O','L'),
 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  */
 305 int avdevice_app_to_dev_control_message(struct AVFormatContext *s,
 306                                         enum AVAppToDevMessageType type,
 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  */
 319 int avdevice_dev_to_app_control_message(struct AVFormatContext *s,
 320                                         enum AVDevToAppMessageType type,
 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 allows 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  */
 399 typedef struct AVDeviceCapabilitiesQuery {
 400     const AVClass *av_class;
 401     AVFormatContext *device_context;
 402     enum AVCodecID codec;
 403     enum AVSampleFormat sample_format;
 404     enum AVPixelFormat pixel_format;
 405     int sample_rate;
 406     int channels;
 407     int64_t channel_layout;
 408     int window_width;
 409     int window_height;
 410     int frame_width;
 411     int frame_height;
 412     AVRational fps;
 413 } AVDeviceCapabilitiesQuery;
 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  */
 437 int avdevice_capabilities_create(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s,
 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  */
 446 void avdevice_capabilities_free(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s);
 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 */
 463 } AVDeviceInfoList;
 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 #endif /* AVDEVICE_AVDEVICE_H */