include/vlc/libvlc.h

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