include/vlc/libvlc.h

   1 /*****************************************************************************
   2  * libvlc.h:  libvlc external API
   3  *****************************************************************************
   4  * Copyright (C) 1998-2009 VLC authors and VideoLAN
   5  *
   6  * Authors: Clément Stenac <zorglub@videolan.org>
   7  *          Jean-Paul Saman <jpsaman@videolan.org>
   8  *          Pierre d'Herbemont <pdherbemont@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /**
  26  * \defgroup libvlc LibVLC
  27  * LibVLC is the external programming interface of the VLC media player.
  28  * It is used to embed VLC into other applications or frameworks.
  29  * @{
  30  * \file
  31  * LibVLC core external API
  32  */
  33
  34 #ifndef VLC_LIBVLC_H
  35 #define VLC_LIBVLC_H 1
  36
  37 #if defined (_WIN32) && defined (DLL_EXPORT)
  38 # define LIBVLC_API __declspec(dllexport)
  39 #elif defined (__GNUC__) && (__GNUC__ >= 4)
  40 # define LIBVLC_API __attribute__((visibility("default")))
  41 #else
  42 # define LIBVLC_API
  43 #endif
  44
  45 #ifdef __LIBVLC__
  46 /* Avoid unhelpful warnings from libvlc with our deprecated APIs */
  47 #   define LIBVLC_DEPRECATED
  48 #elif defined(__GNUC__) && \
  49       (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ > 0)
  50 # define LIBVLC_DEPRECATED __attribute__((deprecated))
  51 #else
  52 # define LIBVLC_DEPRECATED
  53 #endif
  54
  55 #include <stdio.h>
  56 #include <stdarg.h>
  57 #include <stdint.h>
  58
  59 # ifdef __cplusplus
  60 extern "C" {
  61 # endif
  62
  63 /** \defgroup libvlc_core LibVLC core
  64  * \ingroup libvlc
  65  * Before it can do anything useful, LibVLC must be initialized.
  66  * You can create one (or more) instance(s) of LibVLC in a given process,
  67  * with libvlc_new() and destroy them with libvlc_release().
  68  *
  69  * \version Unless otherwise stated, these functions are available
  70  * from LibVLC versions numbered 1.1.0 or more.
  71  * Earlier versions (0.9.x and 1.0.x) are <b>not</b> compatible.
  72  * @{
  73  */
  74
  75 /** This structure is opaque. It represents a libvlc instance */
  76 typedef struct libvlc_instance_t libvlc_instance_t;
  77
  78 typedef int64_t libvlc_time_t;
  79
  80 /** \defgroup libvlc_error LibVLC error handling
  81  * @{
  82  */
  83
  84 /**
  85  * A human-readable error message for the last LibVLC error in the calling
  86  * thread. The resulting string is valid until another error occurs (at least
  87  * until the next LibVLC call).
  88  *
  89  * @warning
  90  * This will be NULL if there was no error.
  91  */
  92 LIBVLC_API const char *libvlc_errmsg (void);
  93
  94 /**
  95  * Clears the LibVLC error status for the current thread. This is optional.
  96  * By default, the error status is automatically overridden when a new error
  97  * occurs, and destroyed when the thread exits.
  98  */
  99 LIBVLC_API void libvlc_clearerr (void);
 100
 101 /**
 102  * Sets the LibVLC error status and message for the current thread.
 103  * Any previous error is overridden.
 104  * \param fmt the format string
 105  * \param ap the arguments
 106  * \return a nul terminated string in any case
 107  */
 108 LIBVLC_API const char *libvlc_vprinterr (const char *fmt, va_list ap);
 109
 110 /**
 111  * Sets the LibVLC error status and message for the current thread.
 112  * Any previous error is overridden.
 113  * \param fmt the format string
 114  * \param args the arguments
 115  * \return a nul terminated string in any case
 116  */
 117 LIBVLC_API const char *libvlc_printerr (const char *fmt, ...);
 118
 119 /**@} */
 120
 121 /**
 122  * Create and initialize a libvlc instance.
 123  * This functions accept a list of "command line" arguments similar to the
 124  * main(). These arguments affect the LibVLC instance default configuration.
 125  *
 126  * \note
 127  * LibVLC may create threads. Therefore, any thread-unsafe process
 128  * initialization must be performed before calling libvlc_new(). In particular
 129  * and where applicable:
 130  * - setlocale() and textdomain(),
 131  * - setenv(), unsetenv() and putenv(),
 132  * - with the X11 display system, XInitThreads()
 133  *   (see also libvlc_media_player_set_xwindow()) and
 134  * - on Microsoft Windows, SetErrorMode().
 135  * - sigprocmask() shall never be invoked; pthread_sigmask() can be used.
 136  *
 137  * On POSIX systems, the SIGCHLD signal <b>must not</b> be ignored, i.e. the
 138  * signal handler must set to SIG_DFL or a function pointer, not SIG_IGN.
 139  * Also while LibVLC is active, the wait() function shall not be called, and
 140  * any call to waitpid() shall use a strictly positive value for the first
 141  * parameter (i.e. the PID). Failure to follow those rules may lead to a
 142  * deadlock or a busy loop.
 143  * Also on POSIX systems, it is recommended that the SIGPIPE signal be blocked,
 144  * even if it is not, in principles, necessary, e.g.:
 145  * @code
 146    sigset_t set;
 147
 148    signal(SIGCHLD, SIG_DFL);
 149    sigemptyset(&set);
 150    sigaddset(&set, SIGPIPE);
 151    pthread_sigmask(SIG_BLOCK, &set, NULL);
 152  * @endcode
 153  *
 154  * On Microsoft Windows, setting the default DLL directories to SYSTEM32
 155  * exclusively is strongly recommended for security reasons:
 156  * @code
 157    SetDefaultDllDirectories(LOAD_LIBRARY_SEARCH_SYSTEM32);
 158  * @endcode
 159  *
 160  * \version
 161  * Arguments are meant to be passed from the command line to LibVLC, just like
 162  * VLC media player does. The list of valid arguments depends on the LibVLC
 163  * version, the operating system and platform, and set of available LibVLC
 164  * plugins. Invalid or unsupported arguments will cause the function to fail
 165  * (i.e. return NULL). Also, some arguments may alter the behaviour or
 166  * otherwise interfere with other LibVLC functions.
 167  *
 168  * \warning
 169  * There is absolutely no warranty or promise of forward, backward and
 170  * cross-platform compatibility with regards to libvlc_new() arguments.
 171  * We recommend that you do not use them, other than when debugging.
 172  *
 173  * \param argc the number of arguments (should be 0)
 174  * \param argv list of arguments (should be NULL)
 175  * \return the libvlc instance or NULL in case of error
 176  */
 177 LIBVLC_API libvlc_instance_t *
 178 libvlc_new( int argc , const char *const *argv );
 179
 180 /**
 181  * Decrement the reference count of a libvlc instance, and destroy it
 182  * if it reaches zero.
 183  *
 184  * \param p_instance the instance to destroy
 185  */
 186 LIBVLC_API void libvlc_release( libvlc_instance_t *p_instance );
 187
 188 /**
 189  * Increments the reference count of a libvlc instance.
 190  * The initial reference count is 1 after libvlc_new() returns.
 191  *
 192  * \param p_instance the instance to reference
 193  */
 194 LIBVLC_API void libvlc_retain( libvlc_instance_t *p_instance );
 195
 196 /**
 197  * Try to start a user interface for the libvlc instance.
 198  *
 199  * \param p_instance the instance
 200  * \param name interface name, or NULL for default
 201  * \return 0 on success, -1 on error.
 202  */
 203 LIBVLC_API
 204 int libvlc_add_intf( libvlc_instance_t *p_instance, const char *name );
 205
 206 /**
 207  * Registers a callback for the LibVLC exit event. This is mostly useful if
 208  * the VLC playlist and/or at least one interface are started with
 209  * libvlc_playlist_play() or libvlc_add_intf() respectively.
 210  * Typically, this function will wake up your application main loop (from
 211  * another thread).
 212  *
 213  * \note This function should be called before the playlist or interface are
 214  * started. Otherwise, there is a small race condition: the exit event could
 215  * be raised before the handler is registered.
 216  *
 217  * \param p_instance LibVLC instance
 218  * \param cb callback to invoke when LibVLC wants to exit,
 219  *           or NULL to disable the exit handler (as by default)
 220  * \param opaque data pointer for the callback
 221  */
 222 LIBVLC_API
 223 void libvlc_set_exit_handler( libvlc_instance_t *p_instance,
 224                               void (*cb) (void *), void *opaque );
 225
 226 /**
 227  * Sets the application name. LibVLC passes this as the user agent string
 228  * when a protocol requires it.
 229  *
 230  * \param p_instance LibVLC instance
 231  * \param name human-readable application name, e.g. "FooBar player 1.2.3"
 232  * \param http HTTP User Agent, e.g. "FooBar/1.2.3 Python/2.6.0"
 233  * \version LibVLC 1.1.1 or later
 234  */
 235 LIBVLC_API
 236 void libvlc_set_user_agent( libvlc_instance_t *p_instance,
 237                             const char *name, const char *http );
 238
 239 /**
 240  * Sets some meta-information about the application.
 241  * See also libvlc_set_user_agent().
 242  *
 243  * \param p_instance LibVLC instance
 244  * \param id Java-style application identifier, e.g. "com.acme.foobar"
 245  * \param version application version numbers, e.g. "1.2.3"
 246  * \param icon application icon name, e.g. "foobar"
 247  * \version LibVLC 2.1.0 or later.
 248  */
 249 LIBVLC_API
 250 void libvlc_set_app_id( libvlc_instance_t *p_instance, const char *id,
 251                         const char *version, const char *icon );
 252
 253 /**
 254  * Retrieve libvlc version.
 255  *
 256  * Example: "1.1.0-git The Luggage"
 257  *
 258  * \return a string containing the libvlc version
 259  */
 260 LIBVLC_API const char * libvlc_get_version(void);
 261
 262 /**
 263  * Retrieve libvlc compiler version.
 264  *
 265  * Example: "gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu6)"
 266  *
 267  * \return a string containing the libvlc compiler version
 268  */
 269 LIBVLC_API const char * libvlc_get_compiler(void);
 270
 271 /**
 272  * Retrieve libvlc changeset.
 273  *
 274  * Example: "aa9bce0bc4"
 275  *
 276  * \return a string containing the libvlc changeset
 277  */
 278 LIBVLC_API const char * libvlc_get_changeset(void);
 279
 280 /**
 281  * Frees an heap allocation returned by a LibVLC function.
 282  * If you know you're using the same underlying C run-time as the LibVLC
 283  * implementation, then you can call ANSI C free() directly instead.
 284  *
 285  * \param ptr the pointer
 286  */
 287 LIBVLC_API void libvlc_free( void *ptr );
 288
 289 /** \defgroup libvlc_event LibVLC asynchronous events
 290  * LibVLC emits asynchronous events.
 291  *
 292  * Several LibVLC objects (such @ref libvlc_instance_t as
 293  * @ref libvlc_media_player_t) generate events asynchronously. Each of them
 294  * provides @ref libvlc_event_manager_t event manager. You can subscribe to
 295  * events with libvlc_event_attach() and unsubscribe with
 296  * libvlc_event_detach().
 297  * @{
 298  */
 299
 300 /**
 301  * Event manager that belongs to a libvlc object, and from whom events can
 302  * be received.
 303  */
 304 typedef struct libvlc_event_manager_t libvlc_event_manager_t;
 305
 306 struct libvlc_event_t;
 307
 308 /**
 309  * Type of a LibVLC event.
 310  */
 311 typedef int libvlc_event_type_t;
 312
 313 /**
 314  * Callback function notification
 315  * \param p_event the event triggering the callback
 316  */
 317 typedef void ( *libvlc_callback_t )( const struct libvlc_event_t *p_event, void *p_data );
 318
 319 /**
 320  * Register for an event notification.
 321  *
 322  * \param p_event_manager the event manager to which you want to attach to.
 323  *        Generally it is obtained by vlc_my_object_event_manager() where
 324  *        my_object is the object you want to listen to.
 325  * \param i_event_type the desired event to which we want to listen
 326  * \param f_callback the function to call when i_event_type occurs
 327  * \param user_data user provided data to carry with the event
 328  * \return 0 on success, ENOMEM on error
 329  */
 330 LIBVLC_API int libvlc_event_attach( libvlc_event_manager_t *p_event_manager,
 331                                         libvlc_event_type_t i_event_type,
 332                                         libvlc_callback_t f_callback,
 333                                         void *user_data );
 334
 335 /**
 336  * Unregister an event notification.
 337  *
 338  * \param p_event_manager the event manager
 339  * \param i_event_type the desired event to which we want to unregister
 340  * \param f_callback the function to call when i_event_type occurs
 341  * \param p_user_data user provided data to carry with the event
 342  */
 343 LIBVLC_API void libvlc_event_detach( libvlc_event_manager_t *p_event_manager,
 344                                          libvlc_event_type_t i_event_type,
 345                                          libvlc_callback_t f_callback,
 346                                          void *p_user_data );
 347
 348 /** @} */
 349
 350 /** \defgroup libvlc_log LibVLC logging
 351  * libvlc_log_* functions provide access to the LibVLC messages log.
 352  * This is used for logging and debugging.
 353  * @{
 354  */
 355
 356 /**
 357  * Logging messages level.
 358  * \note Future LibVLC versions may define new levels.
 359  */
 360 enum libvlc_log_level
 361 {
 362     LIBVLC_DEBUG=0,   /**< Debug message */
 363     LIBVLC_NOTICE=2,  /**< Important informational message */
 364     LIBVLC_WARNING=3, /**< Warning (potential error) message */
 365     LIBVLC_ERROR=4    /**< Error message */
 366 };
 367
 368 typedef struct vlc_log_t libvlc_log_t;
 369
 370 /**
 371  * Gets log message debug infos.
 372  *
 373  * This function retrieves self-debug information about a log message:
 374  * - the name of the VLC module emitting the message,
 375  * - the name of the source code module (i.e. file) and
 376  * - the line number within the source code module.
 377  *
 378  * The returned module name and file name will be NULL if unknown.
 379  * The returned line number will similarly be zero if unknown.
 380  *
 381  * \param ctx message context (as passed to the @ref libvlc_log_cb callback)
 382  * \param module module name storage (or NULL) [OUT]
 383  * \param file source code file name storage (or NULL) [OUT]
 384  * \param line source code file line number storage (or NULL) [OUT]
 385  * \warning The returned module name and source code file name, if non-NULL,
 386  * are only valid until the logging callback returns.
 387  *
 388  * \version LibVLC 2.1.0 or later
 389  */
 390 LIBVLC_API void libvlc_log_get_context(const libvlc_log_t *ctx,
 391                        const char **module, const char **file, unsigned *line);
 392
 393 /**
 394  * Gets log message info.
 395  *
 396  * This function retrieves meta-information about a log message:
 397  * - the type name of the VLC object emitting the message,
 398  * - the object header if any, and
 399  * - a temporaly-unique object identifier.
 400  *
 401  * This information is mainly meant for <b>manual</b> troubleshooting.
 402  *
 403  * The returned type name may be "generic" if unknown, but it cannot be NULL.
 404  * The returned header will be NULL if unset; in current versions, the header
 405  * is used to distinguish for VLM inputs.
 406  * The returned object ID will be zero if the message is not associated with
 407  * any VLC object.
 408  *
 409  * \param ctx message context (as passed to the @ref libvlc_log_cb callback)
 410  * \param name object name storage (or NULL) [OUT]
 411  * \param header object header (or NULL) [OUT]
 412  * \param line source code file line number storage (or NULL) [OUT]
 413  * \warning The returned module name and source code file name, if non-NULL,
 414  * are only valid until the logging callback returns.
 415  *
 416  * \version LibVLC 2.1.0 or later
 417  */
 418 LIBVLC_API void libvlc_log_get_object(const libvlc_log_t *ctx,
 419                         const char **name, const char **header, uintptr_t *id);
 420
 421 /**
 422  * Callback prototype for LibVLC log message handler.
 423  *
 424  * \param data data pointer as given to libvlc_log_set()
 425  * \param level message level (@ref libvlc_log_level)
 426  * \param ctx message context (meta-information about the message)
 427  * \param fmt printf() format string (as defined by ISO C11)
 428  * \param args variable argument list for the format
 429  * \note Log message handlers <b>must</b> be thread-safe.
 430  * \warning The message context pointer, the format string parameters and the
 431  *          variable arguments are only valid until the callback returns.
 432  */
 433 typedef void (*libvlc_log_cb)(void *data, int level, const libvlc_log_t *ctx,
 434                               const char *fmt, va_list args);
 435
 436 /**
 437  * Unsets the logging callback.
 438  *
 439  * This function deregisters the logging callback for a LibVLC instance.
 440  * This is rarely needed as the callback is implicitly unset when the instance
 441  * is destroyed.
 442  *
 443  * \note This function will wait for any pending callbacks invocation to
 444  * complete (causing a deadlock if called from within the callback).
 445  *
 446  * \param p_instance libvlc instance
 447  * \version LibVLC 2.1.0 or later
 448  */
 449 LIBVLC_API void libvlc_log_unset( libvlc_instance_t *p_instance );
 450
 451 /**
 452  * Sets the logging callback for a LibVLC instance.
 453  *
 454  * This function is thread-safe: it will wait for any pending callbacks
 455  * invocation to complete.
 456  *
 457  * \param cb callback function pointer
 458  * \param data opaque data pointer for the callback function
 459  *
 460  * \note Some log messages (especially debug) are emitted by LibVLC while
 461  * is being initialized. These messages cannot be captured with this interface.
 462  *
 463  * \warning A deadlock may occur if this function is called from the callback.
 464  *
 465  * \param p_instance libvlc instance
 466  * \version LibVLC 2.1.0 or later
 467  */
 468 LIBVLC_API void libvlc_log_set( libvlc_instance_t *p_instance,
 469                                 libvlc_log_cb cb, void *data );
 470
 471
 472 /**
 473  * Sets up logging to a file.
 474  * \param p_instance libvlc instance
 475  * \param stream FILE pointer opened for writing
 476  *         (the FILE pointer must remain valid until libvlc_log_unset())
 477  * \version LibVLC 2.1.0 or later
 478  */
 479 LIBVLC_API void libvlc_log_set_file( libvlc_instance_t *p_instance, FILE *stream );
 480
 481 /** @} */
 482
 483 /**
 484  * Description of a module.
 485  */
 486 typedef struct libvlc_module_description_t
 487 {
 488     char *psz_name;
 489     char *psz_shortname;
 490     char *psz_longname;
 491     char *psz_help;
 492     struct libvlc_module_description_t *p_next;
 493 } libvlc_module_description_t;
 494
 495 /**
 496  * Release a list of module descriptions.
 497  *
 498  * \param p_list the list to be released
 499  */
 500 LIBVLC_API
 501 void libvlc_module_description_list_release( libvlc_module_description_t *p_list );
 502
 503 /**
 504  * Returns a list of audio filters that are available.
 505  *
 506  * \param p_instance libvlc instance
 507  *
 508  * \return a list of module descriptions. It should be freed with libvlc_module_description_list_release().
 509  *         In case of an error, NULL is returned.
 510  *
 511  * \see libvlc_module_description_t
 512  * \see libvlc_module_description_list_release
 513  */
 514 LIBVLC_API
 515 libvlc_module_description_t *libvlc_audio_filter_list_get( libvlc_instance_t *p_instance );
 516
 517 /**
 518  * Returns a list of video filters that are available.
 519  *
 520  * \param p_instance libvlc instance
 521  *
 522  * \return a list of module descriptions. It should be freed with libvlc_module_description_list_release().
 523  *         In case of an error, NULL is returned.
 524  *
 525  * \see libvlc_module_description_t
 526  * \see libvlc_module_description_list_release
 527  */
 528 LIBVLC_API
 529 libvlc_module_description_t *libvlc_video_filter_list_get( libvlc_instance_t *p_instance );
 530
 531 /** @} */
 532
 533 /** \defgroup libvlc_clock LibVLC time
 534  * These functions provide access to the LibVLC time/clock.
 535  * @{
 536  */
 537
 538 /**
 539  * Return the current time as defined by LibVLC. The unit is the microsecond.
 540  * Time increases monotonically (regardless of time zone changes and RTC
 541  * adjustements).
 542  * The origin is arbitrary but consistent across the whole system
 543  * (e.g. the system uptim, the time since the system was booted).
 544  * \note On systems that support it, the POSIX monotonic clock is used.
 545  */
 546 LIBVLC_API
 547 int64_t libvlc_clock(void);
 548
 549 /**
 550  * Return the delay (in microseconds) until a certain timestamp.
 551  * \param pts timestamp
 552  * \return negative if timestamp is in the past,
 553  * positive if it is in the future
 554  */
 555 static inline int64_t libvlc_delay(int64_t pts)
 556 {
 557     return pts - libvlc_clock();
 558 }
 559
 560 /** @} */
 561
 562 # ifdef __cplusplus
 563 }
 564 # endif
 565
 566 #endif /** @} */