libMPV.Client.pas

{*
 *  URUWorks libMPV (client.h)
 *
 *  Author  : URUWorks
 *  Website : uruworks.net
 *
 *  The contents of this file are used with permission, subject to
 *  the Mozilla Public License Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  http://www.mozilla.org/MPL/2.0.html
 *
 *  Software distributed under the License is distributed on an
 *  "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing
 *  rights and limitations under the License.
 *
 *  Copyright (C) 2021-2024 URUWorks, uruworks@gmail.com.
 *}

{$PACKRECORDS C}

unit libMPV.Client;

// -----------------------------------------------------------------------------

interface

uses ctypes;

// -----------------------------------------------------------------------------

const
  LIBMPV_DLL_NAME = 'libmpv';
  LIBMPV_DLL_VER : array[0..3] of AnsiString =
    (
    {$IFDEF WINDOWS}'-3', '-2', '-1'{$ELSE}'.3', '.2', '.1'{$ENDIF}, ''
    );

type
  Pmpv_handle = ^mpv_handle;
  mpv_handle = THandle;

  { Copyright (C) 2017 the mpv developers
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
    }
  {
   * Note: the client API is licensed under ISC (see above) to enable
   * other wrappers outside of mpv. But keep in mind that the
   * mpv core is by default still GPLv2+ - unless built with
   * --enable-lgpl, which makes it LGPLv2+.
    }
  { New symbols must still be added to libmpv/mpv.def.  }
  {*
   * Mechanisms provided by this API
   * -------------------------------
   *
   * This API provides general control over mpv playback. It does not give you
   * direct access to individual components of the player, only the whole thing.
   * It's somewhat equivalent to MPlayer's slave mode. You can send commands,
   * retrieve or set playback status or settings with properties, and receive
   * events.
   *
   * The API can be used in two ways:
   * 1) Internally in mpv, to provide additional features to the command line
   *    player. Lua scripting uses this. (Currently there is no plugin API to
   *    get a client API handle in external user code. It has to be a fixed
   *    part of the player at compilation time.)
   * 2) Using mpv as a library with mpv_create(). This basically allows embedding
   *    mpv in other applications.
   *
   * Documentation
   * -------------
   *
   * The libmpv C API is documented directly in this header. Note that most
   * actual interaction with this player is done through
   * options/commands/properties, which can be accessed through this API.
   * Essentially everything is done with them, including loading a file,
   * retrieving playback progress, and so on.
   *
   * These are documented elsewhere:
   *      * http://mpv.io/manual/master/#options
   *      * http://mpv.io/manual/master/#list-of-input-commands
   *      * http://mpv.io/manual/master/#properties
   *
   * You can also look at the examples here:
   *      * https://github.com/mpv-player/mpv-examples/tree/master/libmpv
   *
   * Event loop
   * ----------
   *
   * In general, the API user should run an event loop in order to receive events.
   * This event loop should call mpv_wait_event(), which will return once a new
   * mpv client API is available. It is also possible to integrate client API
   * usage in other event loops (e.g. GUI toolkits) with the
   * mpv_set_wakeup_callback() function, and then polling for events by calling
   * mpv_wait_event() with a 0 timeout.
   *
   * Note that the event loop is detached from the actual player. Not calling
   * mpv_wait_event() will not stop playback. It will eventually congest the
   * event queue of your API handle, though.
   *
   * Synchronous vs. asynchronous calls
   * ----------------------------------
   *
   * The API allows both synchronous and asynchronous calls. Synchronous calls
   * have to wait until the playback core is ready, which currently can take
   * an unbounded time (e.g. if network is slow or unresponsive). Asynchronous
   * calls just queue operations as requests, and return the result of the
   * operation as events.
   *
   * Asynchronous calls
   * ------------------
   *
   * The client API includes asynchronous functions. These allow you to send
   * requests instantly, and get replies as events at a later point. The
   * requests are made with functions carrying the _async suffix, and replies
   * are returned by mpv_wait_event() (interleaved with the normal event stream).
   *
   * A 64 bit userdata value is used to allow the user to associate requests
   * with replies. The value is passed as reply_userdata parameter to the request
   * function. The reply to the request will have the reply
   * mpv_event->reply_userdata field set to the same value as the
   * reply_userdata parameter of the corresponding request.
   *
   * This userdata value is arbitrary and is never interpreted by the API. Note
   * that the userdata value 0 is also allowed, but then the client must be
   * careful not accidentally interpret the mpv_event->reply_userdata if an
   * event is not a reply. (For non-replies, this field is set to 0.)
   *
   * Asynchronous calls may be reordered in arbitrarily with other synchronous
   * and asynchronous calls. If you want a guaranteed order, you need to wait
   * until asynchronous calls report completion before doing the next call.
   *
   * See also the section "Asynchronous command details" in the manpage.
   *
   * Multithreading
   * --------------
   *
   * The client API is generally fully thread-safe, unless otherwise noted.
   * Currently, there is no real advantage in using more than 1 thread to access
   * the client API, since everything is serialized through a single lock in the
   * playback core.
   *
   * Basic environment requirements
   * ------------------------------
   *
   * This documents basic requirements on the C environment. This is especially
   * important if mpv is used as library with mpv_create().
   *
   * - The LC_NUMERIC locale category must be set to "C". If your program calls
   *   setlocale(), be sure not to use LC_ALL, or if you do, reset LC_NUMERIC
   *   to its sane default: setlocale(LC_NUMERIC, "C").
   * - If a X11 based VO is used, mpv will set the xlib error handler. This error
   *   handler is process-wide, and there's no proper way to share it with other
   *   xlib users within the same process. This might confuse GUI toolkits.
   * - mpv uses some other libraries that are not library-safe, such as Fribidi
   *   (used through libass), ALSA, FFmpeg, and possibly more.
   * - The FPU precision must be set at least to double precision.
   * - On Windows, mpv will call timeBeginPeriod(1).
   * - On memory exhaustion, mpv will kill the process.
   * - In certain cases, mpv may start sub processes (such as with the ytdl
   *   wrapper script).
   * - Using UNIX IPC (off by default) will override the SIGPIPE signal handler,
   *   and set it to SIG_IGN. Some invocations of the "subprocess" command will
   *   also do that.
   * - mpv may start sub processes, so overriding SIGCHLD, or waiting on all PIDs
   *   (such as calling wait()) by the parent process or any other library within
   *   the process must be avoided. libmpv itself only waits for its own PIDs.
   * - If anything in the process registers signal handlers, they must set the
   *   SA_RESTART flag. Otherwise you WILL get random failures on signals.
   *
   * Encoding of filenames
   * ---------------------
   *
   * mpv uses UTF-8 everywhere.
   *
   * On some platforms (like Linux), filenames actually do not have to be UTF-8;
   * for this reason libmpv supports non-UTF-8 strings. libmpv uses what the
   * kernel uses and does not recode filenames. At least on Linux, passing a
   * string to libmpv is like passing a string to the fopen() function.
   *
   * On Windows, filenames are always UTF-8, libmpv converts between UTF-8 and
   * UTF-16 when using win32 API functions. libmpv never uses or accepts
   * filenames in the local 8 bit encoding. It does not use fopen() either;
   * it uses _wfopen().
   *
   * On OS X, filenames and other strings taken/returned by libmpv can have
   * inconsistent unicode normalization. This can sometimes lead to problems.
   * You have to hope for the best.
   *
   * Also see the remarks for MPV_FORMAT_STRING.
   *
   * Embedding the video window
   * --------------------------
   *
   * Using the render API (in render_cb.h) is recommended. This API requires
   * you to create and maintain an OpenGL context, to which you can render
   * video using a specific API call. This API does not include keyboard or mouse
   * input directly.
   *
   * There is an older way to embed the native mpv window into your own. You have
   * to get the raw window handle, and set it as "wid" option. This works on X11,
   * win32, and OSX only. It's much easier to use than the render API, but
   * also has various problems.
   *
   * Also see client API examples and the mpv manpage. There is an extensive
   * discussion here:
   * https://github.com/mpv-player/mpv-examples/tree/master/libmpv#methods-of-embedding-the-video-window
   *
   * Compatibility
   * -------------
   *
   * mpv development doesn't stand still, and changes to mpv internals as well as
   * to its interface can cause compatibility issues to client API users.
   *
   * The API is versioned (see MPV_CLIENT_API_VERSION), and changes to it are
   * documented in DOCS/client-api-changes.rst. The C API itself will probably
   * remain compatible for a long time, but the functionality exposed by it
   * could change more rapidly. For example, it's possible that options are
   * renamed, or change the set of allowed values.
   *
   * Defensive programming should be used to potentially deal with the fact that
   * options, commands, and properties could disappear, change their value range,
   * or change the underlying datatypes. It might be a good idea to prefer
   * MPV_FORMAT_STRING over other types to decouple your code from potential
   * mpv changes.
   *
   * Also see: DOCS/compatibility.rst
   *
   * Future changes
   * --------------
   *
   * This are the planned changes that will most likely be done on the next major
   * bump of the library:
   *
   *  - remove all symbols that are marked as deprecated
   *  - reassign enum numerical values to remove gaps
   *  - disabling all events by default
    }
  {*
   * The version is incremented on each API change. The 16 lower bits form the
   * minor version number, and the 16 higher bits the major version number. If
   * the API becomes incompatible to previous versions, the major version
   * number is incremented. This affects only C part, and not properties and
   * options.
   *
   * Every API bump is described in DOCS/client-api-changes.rst
   *
   * You can use MPV_MAKE_VERSION() and compare the result with integer
   * relational operators (<, >, <=, >=).
    }

  function LIBMPV_MAKE_VERSION(major, minor: Integer): Integer;
  function LIBMPV_CLIENT_API_VERSION: Integer;

  {*
   * The API user is allowed to "#define MPV_ENABLE_DEPRECATED 0" before
   * including any libmpv headers. Then deprecated symbols will be excluded
   * from the headers. (Of course, deprecated properties and commands and
   * other functionality will still work.)
    }

  const
    MPV_ENABLE_DEPRECATED = 1;

  {*
   * Return the MPV_CLIENT_API_VERSION the mpv source has been compiled with.
    }

  var
    mpv_client_api_version : function:dword;cdecl;

  {*
   * Client context used by the client API. Every client has its own private
   * handle.
    }

  type
    mpv_error = Longint;

  const
  {*
   * List of error codes than can be returned by API functions. 0 and positive
   * return values always mean success, negative values are always errors.
    }
  {*
       * No error happened (used to signal successful operation).
       * Keep in mind that many API functions returning error codes can also
       * return positive values, which also indicate success. API users can
       * hardcode the fact that ">= 0" means success.
        }

      MPV_ERROR_SUCCESS = 0;

  {*
       * The event ringbuffer is full. This means the client is choked, and can't
       * receive any events. This can happen when too many asynchronous requests
       * have been made, but not answered. Probably never happens in practice,
       * unless the mpv core is frozen for some reason, and the client keeps
       * making asynchronous requests. (Bugs in the client API implementation
       * could also trigger this, e.g. if events become "lost".)
        }

      MPV_ERROR_EVENT_QUEUE_FULL = -1;

  {*
       * Memory allocation failed.
        }

      MPV_ERROR_NOMEM = -2;

  {*
       * The mpv core wasn't configured and initialized yet. See the notes in
       * mpv_create().
        }

      MPV_ERROR_UNINITIALIZED = -3;

  {*
       * Generic catch-all error if a parameter is set to an invalid or
       * unsupported value. This is used if there is no better error code.
        }

      MPV_ERROR_INVALID_PARAMETER = -4;

  {*
       * Trying to set an option that doesn't exist.
        }

      MPV_ERROR_OPTION_NOT_FOUND = -5;

  {*
       * Trying to set an option using an unsupported MPV_FORMAT.
        }

      MPV_ERROR_OPTION_FORMAT = -6;

  {*
       * Setting the option failed. Typically this happens if the provided option
       * value could not be parsed.
        }

      MPV_ERROR_OPTION_ERROR = -7;

  {*
       * The accessed property doesn't exist.
        }

      MPV_ERROR_PROPERTY_NOT_FOUND = -8;

  {*
       * Trying to set or get a property using an unsupported MPV_FORMAT.
        }

      MPV_ERROR_PROPERTY_FORMAT = -9;

  {*
       * The property exists, but is not available. This usually happens when the
       * associated subsystem is not active, e.g. querying audio parameters while
       * audio is disabled.
        }

      MPV_ERROR_PROPERTY_UNAVAILABLE = -10;

  {*
       * Error setting or getting a property.
        }

      MPV_ERROR_PROPERTY_ERROR = -11;

  {*
       * General error when running a command with mpv_command and similar.
        }

      MPV_ERROR_COMMAND = -12;

  {*
       * Generic error on loading (usually used with mpv_event_end_file.error).
        }

      MPV_ERROR_LOADING_FAILED = -13;

  {*
       * Initializing the audio output failed.
        }

      MPV_ERROR_AO_INIT_FAILED = -14;

  {*
       * Initializing the video output failed.
        }

      MPV_ERROR_VO_INIT_FAILED = -15;

  {*
       * There was no audio or video data to play. This also happens if the
       * file was recognized, but did not contain any audio or video streams,
       * or no streams were selected.
        }

      MPV_ERROR_NOTHING_TO_PLAY = -16;

  {*
       * When trying to load the file, the file format could not be determined,
       * or the file was too broken to open it.
        }

      MPV_ERROR_UNKNOWN_FORMAT = -17;

  {*
       * Generic error for signaling that certain system requirements are not
       * fulfilled.
        }

      MPV_ERROR_UNSUPPORTED = -18;

  {*
       * The API function which was called is a stub only.
        }

      MPV_ERROR_NOT_IMPLEMENTED = -19;

  {*
       * Unspecified error.
        }

      MPV_ERROR_GENERIC = -20;

  {*
   * Return a string describing the error. For unknown errors, the string
   * "unknown error" is returned.
   *
   * @param error error number, see enum mpv_error
   * @return A static string describing the error. The string is completely
   *         static, i.e. doesn't need to be deallocated, and is valid forever.
    }

  var
    mpv_error_string : function(error:Longint):Pchar;cdecl;

  {*
   * General function to deallocate memory returned by some of the API functions.
   * Call this only if it's explicitly documented as allowed. Calling this on
   * mpv memory not owned by the caller will lead to undefined behavior.
   *
   * @param data A valid pointer returned by the API, or NULL.
    }

  mpv_free : procedure(var data:pointer);cdecl;

  {*
   * Return the name of this client handle. Every client has its own unique
   * name, which is mostly used for user interface purposes.
   *
   * @return The client name. The string is read-only and is valid until the
   *         mpv_handle is destroyed.
    }

  mpv_client_name : function(var ctx:mpv_handle):Pchar;cdecl;

  {*
   * Return the ID of this client handle. Every client has its own unique ID. This
   * ID is never reused by the core, even if the mp v_handle at hand gets destroyed
   * and new handles get allocated.
   *
   * IDs are never 0 or negative.
   *
   * Some mpv APIs (not necessarily all) accept a name in the form "@<id>" in
   * addition of the proper mpv_client_name(), where "<id>" is the ID in decimal
   * form (e.g. "@123"). For example, the "script-message-to" command takes the
   * client name as first argument, but also accepts the client ID formatted in
   * this manner.
   *
   * @return The client ID.
    }

  mpv_client_id : function(var ctx:mpv_handle):int64;cdecl;

  {*
   * Create a new mpv instance and an associated client API handle to control
   * the mpv instance. This instance is in a pre-initialized state,
   * and needs to be initialized to be actually used with most other API
   * functions.
   *
   * Some API functions will return MPV_ERROR_UNINITIALIZED in the uninitialized
   * state. You can call mpv_set_property() (or mpv_set_property_string() and
   * other variants, and before mpv 0.21.0 mpv_set_option() etc.) to set initial
   * options. After this, call mpv_initialize() to start the player, and then use
   * e.g. mpv_command() to start playback of a file.
   *
   * The point of separating handle creation and actual initialization is that
   * you can configure things which can't be changed during runtime.
   *
   * Unlike the command line player, this will have initial settings suitable
   * for embedding in applications. The following settings are different:
   * - stdin/stdout/stderr and the terminal will never be accessed. This is
   *   equivalent to setting the --no-terminal option.
   *   (Technically, this also suppresses C signal handling.)
   * - No config files will be loaded. This is roughly equivalent to using
   *   --config=no. Since libmpv 1.15, you can actually re-enable this option,
   *   which will make libmpv load config files during mpv_initialize(). If you
   *   do this, you are strongly encouraged to set the "config-dir" option too.
   *   (Otherwise it will load the mpv command line player's config.)
   *   For example:
   *      mpv_set_option_string(mpv, "config-dir", "/my/path"); // set config root
   *      mpv_set_option_string(mpv, "config", "yes"); // enable config loading
   *      (call mpv_initialize() _after_ this)
   * - Idle mode is enabled, which means the playback core will enter idle mode
   *   if there are no more files to play on the internal playlist, instead of
   *   exiting. This is equivalent to the --idle option.
   * - Disable parts of input handling.
   * - Most of the different settings can be viewed with the command line player
   *   by running "mpv --show-profile=libmpv".
   *
   * All this assumes that API users want a mpv instance that is strictly
   * isolated from the command line player's configuration, user settings, and
   * so on. You can re-enable disabled features by setting the appropriate
   * options.
   *
   * The mpv command line parser is not available through this API, but you can
   * set individual options with mpv_set_property(). Files for playback must be
   * loaded with mpv_command() or others.
   *
   * Note that you should avoid doing concurrent accesses on the uninitialized
   * client handle. (Whether concurrent access is definitely allowed or not has
   * yet to be decided.)
   *
   * @return a new mpv client API handle. Returns NULL on error. Currently, this
   *         can happen in the following situations:
   *         - out of memory
   *         - LC_NUMERIC is not set to "C" (see general remarks)
    }

  mpv_create : function:Pmpv_handle;cdecl;

  {*
   * Initialize an uninitialized mpv instance. If the mpv instance is already
   * running, an error is returned.
   *
   * This function needs to be called to make full use of the client API if the
   * client API handle was created with mpv_create().
   *
   * Only the following options are required to be set _before_ mpv_initialize():
   *      - options which are only read at initialization time:
   *        - config
   *        - config-dir
   *        - input-conf
   *        - load-scripts
   *        - script
   *        - player-operation-mode
   *        - input-app-events (OSX)
   *      - all encoding mode options
   *
   * @return error code
    }

  mpv_initialize : function(var ctx:mpv_handle):longint;cdecl;

  {*
   * Disconnect and destroy the mpv_handle. ctx will be deallocated with this
   * API call.
   *
   * If the last mpv_handle is detached, the core player is destroyed. In
   * addition, if there are only weak mpv_handles (such as created by
   * mpv_create_weak_client() or internal scripts), these mpv_handles will
   * be sent MPV_EVENT_SHUTDOWN. This function may block until these clients
   * have responded to the shutdown event, and the core is finally destroyed.
    }

  mpv_destroy : procedure(var ctx:mpv_handle);cdecl;

  {*
   * Similar to mpv_destroy(), but brings the player and all clients down
   * as well, and waits until all of them are destroyed. This function blocks. The
   * advantage over mpv_destroy() is that while mpv_destroy() merely
   * detaches the client handle from the player, this function quits the player,
   * waits until all other clients are destroyed (i.e. all mpv_handles are
   * detached), and also waits for the final termination of the player.
   *
   * Since mpv_destroy() is called somewhere on the way, it's not safe to
   * call other functions concurrently on the same context.
   *
   * Since mpv client API version 1.29:
   *  The first call on any mpv_handle will block until the core is destroyed.
   *  This means it will wait until other mpv_handle have been destroyed. If you
   *  want asynchronous destruction, just run the "quit" command, and then react
   *  to the MPV_EVENT_SHUTDOWN event.
   *  If another mpv_handle already called mpv_terminate_destroy(), this call will
   *  not actually block. It will destroy the mpv_handle, and exit immediately,
   *  while other mpv_handles might still be uninitializing.
   *
   * Before mpv client API version 1.29:
   *  If this is called on a mpv_handle that was not created with mpv_create(),
   *  this function will merely send a quit command and then call
   *  mpv_destroy(), without waiting for the actual shutdown.
    }

  mpv_terminate_destroy : procedure(var ctx:mpv_handle);cdecl;

  {*
   * Create a new client handle connected to the same player core as ctx. This
   * context has its own event queue, its own mpv_request_event() state, its own
   * mpv_request_log_messages() state, its own set of observed properties, and
   * its own state for asynchronous operations. Otherwise, everything is shared.
   *
   * This handle should be destroyed with mpv_destroy() if no longer
   * needed. The core will live as long as there is at least 1 handle referencing
   * it. Any handle can make the core quit, which will result in every handle
   * receiving MPV_EVENT_SHUTDOWN.
   *
   * This function can not be called before the main handle was initialized with
   * mpv_initialize(). The new handle is always initialized, unless ctx=NULL was
   * passed.
   *
   * @param ctx Used to get the reference to the mpv core; handle-specific
   *            settings and parameters are not used.
   *            If NULL, this function behaves like mpv_create() (ignores name).
   * @param name The client name. This will be returned by mpv_client_name(). If
   *             the name is already in use, or contains non-alphanumeric
   *             characters (other than '_'), the name is modified to fit.
   *             If NULL, an arbitrary name is automatically chosen.
   * @return a new handle, or NULL on error
    }

  mpv_create_client : function(var ctx:mpv_handle; const name:Pchar):Pmpv_handle;cdecl;

  {*
   * This is the same as mpv_create_client(), but the created mpv_handle is
   * treated as a weak reference. If all mpv_handles referencing a core are
   * weak references, the core is automatically destroyed. (This still goes
   * through normal uninit of course. Effectively, if the last non-weak mpv_handle
   * is destroyed, then the weak mpv_handles receive MPV_EVENT_SHUTDOWN and are
   * asked to terminate as well.)
   *
   * Note if you want to use this like refcounting: you have to be aware that
   * mpv_terminate_destroy() _and_ mpv_destroy() for the last non-weak
   * mpv_handle will block until all weak mpv_handles are destroyed.
    }

  mpv_create_weak_client : function(var ctx:mpv_handle; const name:Pchar):Pmpv_handle;cdecl;

  {*
   * Load a config file. This loads and parses the file, and sets every entry in
   * the config file's default section as if mpv_set_option_string() is called.
   *
   * The filename should be an absolute path. If it isn't, the actual path used
   * is unspecified. (Note: an absolute path starts with '/' on UNIX.) If the
   * file wasn't found, MPV_ERROR_INVALID_PARAMETER is returned.
   *
   * If a fatal error happens when parsing a config file, MPV_ERROR_OPTION_ERROR
   * is returned. Errors when setting options as well as other types or errors
   * are ignored (even if options do not exist). You can still try to capture
   * the resulting error messages with mpv_request_log_messages(). Note that it's
   * possible that some options were successfully set even if any of these errors
   * happen.
   *
   * @param filename absolute path to the config file on the local filesystem
   * @return error code
    }

  mpv_load_config_file : function(var ctx:mpv_handle; filename:Pchar):longint;cdecl;

  {*
   * Return the internal time in nanoseconds. This has an arbitrary start offset,
   * but will never wrap or go backwards.
   *
   * Note that this is always the real time, and doesn't necessarily have to do
   * with playback time. For example, playback could go faster or slower due to
   * playback speed, or due to playback being paused. Use the "time-pos" property
   * instead to get the playback status.
   *
   * Unlike other libmpv APIs, this can be called at absolutely any time (even
   * within wakeup callbacks), as long as the context is valid.
   *
   * Safe to be called from mpv render API threads.
    }

  mpv_get_time_ns : function(var ctx:mpv_handle):int64;cdecl;

  {*
   * Same as mpv_get_time_ns but in microseconds.
   *}

  mpv_get_time_us : function(var ctx:mpv_handle):int64;cdecl;

  {*
   * Data format for options and properties. The API functions to get/set
   * properties and options support multiple formats, and this enum describes
   * them.
    }

  type
    mpv_format = Longint;
    const

  {*
       * Invalid. Sometimes used for empty values. This is always defined to 0,
       * so a normal 0-init of mpv_format (or e.g. mpv_node) is guaranteed to set
       * this it to MPV_FORMAT_NONE (which makes some things saner as consequence).
        }

    MPV_FORMAT_NONE = 0;

  {*
       * The basic type is char*. It returns the raw property string, like
       * using $=property in input.conf (see input.rst).
       *
       * NULL isn't an allowed value.
       *
       * Warning: although the encoding is usually UTF-8, this is not always the
       *          case. File tags often store strings in some legacy codepage,
       *          and even filenames don't necessarily have to be in UTF-8 (at
       *          least on Linux). If you pass the strings to code that requires
       *          valid UTF-8, you have to sanitize it in some way.
       *          On Windows, filenames are always UTF-8, and libmpv converts
       *          between UTF-8 and UTF-16 when using win32 API functions. See
       *          the "Encoding of filenames" section for details.
       *
       * Example for reading:
       *
       *     char *result = NULL;
       *     if (mpv_get_property(ctx, "property", MPV_FORMAT_STRING, &result) < 0)
       *         goto error;
       *     printf("%s\n", result);
       *     mpv_free(result);
       *
       * Or just use mpv_get_property_string().
       *
       * Example for writing:
       *
       *     char *value = "the new value";
       *     // yep, you pass the address to the variable
       *     // (needed for symmetry with other types and mpv_get_property)
       *     mpv_set_property(ctx, "property", MPV_FORMAT_STRING, &value);
       *
       * Or just use mpv_set_property_string().
       *
        }

    MPV_FORMAT_STRING = 1;

  {*
       * The basic type is char*. It returns the OSD property string, like
       * using $property in input.conf (see input.rst). In many cases, this
       * is the same as the raw string, but in other cases it's formatted for
       * display on OSD. It's intended to be human readable. Do not attempt to
       * parse these strings.
       *
       * Only valid when doing read access. The rest works like MPV_FORMAT_STRING.
        }

    MPV_FORMAT_OSD_STRING = 2;

  {*
       * The basic type is int. The only allowed values are 0 ("no")
       * and 1 ("yes").
       *
       * Example for reading:
       *
       *     int result;
       *     if (mpv_get_property(ctx, "property", MPV_FORMAT_FLAG, &result) < 0)
       *         goto error;
       *     printf("%s\n", result ? "true" : "false");
       *
       * Example for writing:
       *
       *     int flag = 1;
       *     mpv_set_property(ctx, "property", MPV_FORMAT_FLAG, &flag);
        }

    MPV_FORMAT_FLAG = 3;

  {*
       * The basic type is int64.
        }

    MPV_FORMAT_INT64 = 4;

  {*
       * The basic type is double.
        }

    MPV_FORMAT_DOUBLE = 5;

  {*
       * The type is mpv_node.
       *
       * For reading, you usually would pass a pointer to a stack-allocated
       * mpv_node value to mpv, and when you're done you call
       * mpv_free_node_contents(&node).
       * You're expected not to write to the data - if you have to, copy it
       * first (which you have to do manually).
       *
       * For writing, you construct your own mpv_node, and pass a pointer to the
       * API. The API will never write to your data (and copy it if needed), so
       * you're free to use any form of allocation or memory management you like.
       *
       * Warning: when reading, always check the mpv_node.format member. For
       *          example, properties might change their type in future versions
       *          of mpv, or sometimes even during runtime.
       *
       * Example for reading:
       *
       *     mpv_node result;
       *     if (mpv_get_property(ctx, "property", MPV_FORMAT_NODE, &result) < 0)
       *         goto error;
       *     printf("format=%d\n", (int)result.format);
       *     mpv_free_node_contents(&result).
       *
       * Example for writing:
       *
       *     mpv_node value;
       *     value.format = MPV_FORMAT_STRING;
       *     value.u.string = "hello";
       *     mpv_set_property(ctx, "property", MPV_FORMAT_NODE, &value);
        }

    MPV_FORMAT_NODE = 6;

  {*
       * Used with mpv_node only. Can usually not be used directly.
        }

    MPV_FORMAT_NODE_ARRAY = 7;

  {*
       * See MPV_FORMAT_NODE_ARRAY.
        }

    MPV_FORMAT_NODE_MAP = 8;

  {*
       * A raw, untyped byte array. Only used only with mpv_node, and only in
       * some very specific situations. (Some commands use it.)
        }

    MPV_FORMAT_BYTE_ARRAY = 9;

  {*
   * Generic data storage.
   *
   * If mpv writes this struct (e.g. via mpv_get_property()), you must not change
   * the data. In some cases (mpv_get_property()), you have to free it with
   * mpv_free_node_contents(). If you fill this struct yourself, you're also
   * responsible for freeing it, and you must not call mpv_free_node_contents().
    }

  type
    Pmpv_node_list = ^mpv_node_list;
    Pmpv_byte_array = ^mpv_byte_array;

    Pmpv_node = ^mpv_node;
    mpv_node =  record
        u :  record
            case Integer of
              {* valid if format==MPV_FORMAT_STRING }
              0 : ( _string : Pchar );
              {* valid if format==MPV_FORMAT_FLAG }
              1 : ( flag : longint );
              {* valid if format==MPV_FORMAT_INT64 }
              2 : ( int64_ : int64 );
              {* valid if format==MPV_FORMAT_DOUBLE }
              3 : ( double_ : double );
              {* valid if format==MPV_FORMAT_NODE_ARRAY or if format==MPV_FORMAT_NODE_MAP }
              4 : ( list : Pmpv_node_list );
              {* valid if format==MPV_FORMAT_BYTE_ARRAY }
              5 : ( ba : Pmpv_byte_array );
            end;

       {*
        * Type of the data stored in this struct. This value rules what members in
        * the given union can be accessed. The following formats are currently
        * defined to be allowed in mpv_node:
        *
        *  MPV_FORMAT_STRING       (u.string)
        *  MPV_FORMAT_FLAG         (u.flag)
        *  MPV_FORMAT_INT64        (u.int64)
        *  MPV_FORMAT_DOUBLE       (u.double_)
        *  MPV_FORMAT_NODE_ARRAY   (u.list)
        *  MPV_FORMAT_NODE_MAP     (u.list)
        *  MPV_FORMAT_BYTE_ARRAY   (u.ba)
        *  MPV_FORMAT_NONE         (no member)
        *
        * If you encounter a value you don't know, you must not make any
        * assumptions about the contents of union u.
         }
        format : mpv_format;
      end;

   {*
    * (see mpv_node)
     }

    mpv_node_list =  record
       {* Number of entries. Negative values are not allowed. }
        num : Longint;
        {*
         * MPV_FORMAT_NODE_ARRAY:
         *  values[N] refers to value of the Nth item
         *
         * MPV_FORMAT_NODE_MAP:
         *  values[N] refers to value of the Nth key/value pair
         *
         * If num > 0, values[0] to values[num-1] (inclusive) are valid.
         * Otherwise, this can be NULL.
          }
        values : Pmpv_node;
        {*
         * MPV_FORMAT_NODE_ARRAY:
         *  unused (typically NULL), access is not allowed
         *
         * MPV_FORMAT_NODE_MAP:
         *  keys[N] refers to key of the Nth key/value pair. If num > 0, keys[0] to
         *  keys[num-1] (inclusive) are valid. Otherwise, this can be NULL.
         *  The keys are in random order. The only guarantee is that keys[N] belongs
         *  to the value values[N]. NULL keys are not allowed.
          }
        keys : PPchar;
      end;

  {*
   * (see mpv_node)
    }

    mpv_byte_array =  record
        {*
         * Pointer to the data. In what format the data is stored is up to whatever
         * uses MPV_FORMAT_BYTE_ARRAY.
         }
        data : pointer;
        {*
         * Size of the data pointed to by ptr.
          }
        size : csize_t;
      end;

  {*
   * Frees any data referenced by the node. It doesn't free the node itself.
   * Call this only if the mpv client API set the node. If you constructed the
   * node yourself (manually), you have to free it yourself.
   *
   * If node->format is MPV_FORMAT_NONE, this call does nothing. Likewise, if
   * the client API sets a node with this format, this function doesn't need to
   * be called. (This is just a clarification that there's no danger of anything
   * strange happening in these cases.)
    }

  var
    mpv_free_node_contents : procedure(var node:mpv_node);cdecl;

  {*
   * Set an option. Note that you can't normally set options during runtime. It
   * works in uninitialized state (see mpv_create()), and in some cases in at
   * runtime.
   *
   * Using a format other than MPV_FORMAT_NODE is equivalent to constructing a
   * mpv_node with the given format and data, and passing the mpv_node to this
   * function.
   *
   * Note: this is semi-deprecated. For most purposes, this is not needed anymore.
   *       Starting with mpv version 0.21.0 (version 1.23) most options can be set
   *       with mpv_set_property() (and related functions), and even before
   *       mpv_initialize(). In some obscure corner cases, using this function
   *       to set options might still be required (see
   *       "Inconsistencies between options and properties" in the manpage). Once
   *       these are resolved, the option setting functions might be fully
   *       deprecated.
   *
   * @param name Option name. This is the same as on the mpv command line, but
   *             without the leading "--".
   * @param format see enum mpv_format.
   * @param[in] data Option value (according to the format).
   * @return error code
    }

  mpv_set_option : function(var ctx:mpv_handle; name:Pchar; format:mpv_format; data:pointer):longint;cdecl;

  {*
   * Convenience function to set an option to a string value. This is like
   * calling mpv_set_option() with MPV_FORMAT_STRING.
   *
   * @return error code
    }

  mpv_set_option_string : function(var ctx:mpv_handle; name:Pchar; data:Pchar):longint;cdecl;

  {*
   * Send a command to the player. Commands are the same as those used in
   * input.conf, except that this function takes parameters in a pre-split
   * form.
   *
   * The commands and their parameters are documented in input.rst.
   *
   * Does not use OSD and string expansion by default (unlike mpv_command_string()
   * and input.conf).
   *
   * @param[in] args NULL-terminated list of strings. Usually, the first item
   *                 is the command, and the following items are arguments.
   * @return error code
    }

  mpv_command : function(var ctx:mpv_handle; args:PPchar):longint;cdecl;

  {*
   * Same as mpv_command(), but allows passing structured data in any format.
   * In particular, calling mpv_command() is exactly like calling
   * mpv_command_node() with the format set to MPV_FORMAT_NODE_ARRAY, and
   * every arg passed in order as MPV_FORMAT_STRING.
   *
   * Does not use OSD and string expansion by default.
   *
   * The args argument can have one of the following formats:
   *
   * MPV_FORMAT_NODE_ARRAY:
   *      Positional arguments. Each entry is an argument using an arbitrary
   *      format (the format must be compatible to the used command). Usually,
   *      the first item is the command name (as MPV_FORMAT_STRING). The order
   *      of arguments is as documented in each command description.
   *
   * MPV_FORMAT_NODE_MAP:
   *      Named arguments. This requires at least an entry with the key "name"
   *      to be present, which must be a string, and contains the command name.
   *      The special entry "_flags" is optional, and if present, must be an
   *      array of strings, each being a command prefix to apply. All other
   *      entries are interpreted as arguments. They must use the argument names
   *      as documented in each command description. Some commands do not
   *      support named arguments at all, and must use MPV_FORMAT_NODE_ARRAY.
   *
   * @param[in] args mpv_node with format set to one of the values documented
   *                 above (see there for details)
   * @param[out] result Optional, pass NULL if unused. If not NULL, and if the
   *                    function succeeds, this is set to command-specific return
   *                    data. You must call mpv_free_node_contents() to free it
   *                    (again, only if the command actually succeeds).
   *                    Not many commands actually use this at all.
   * @return error code (the result parameter is not set on error)
    }

  mpv_command_node : function(var ctx:mpv_handle; var args:mpv_node; var result:mpv_node):cint;cdecl;

  {*
   * This is essentially identical to mpv_command() but it also returns a result.
   *
   * Does not use OSD and string expansion by default.
   *
   * @param[in] args NULL-terminated list of strings. Usually, the first item
   *                 is the command, and the following items are arguments.
   * @param[out] result Optional, pass NULL if unused. If not NULL, and if the
   *                    function succeeds, this is set to command-specific return
   *                    data. You must call mpv_free_node_contents() to free it
   *                    (again, only if the command actually succeeds).
   *                    Not many commands actually use this at all.
   * @return error code (the result parameter is not set on error)
    }

  mpv_command_ret : function(var ctx:mpv_handle; args:PPchar; var result:mpv_node):integer;cdecl;

  {*
   * Same as mpv_command, but use input.conf parsing for splitting arguments.
   * This is slightly simpler, but also more error prone, since arguments may
   * need quoting/escaping.
   *
   * This also has OSD and string expansion enabled by default.
    }

  mpv_command_string : function(var ctx:mpv_handle; args:Pchar):longint;cdecl;

  {*
   * Same as mpv_command, but run the command asynchronously.
   *
   * Commands are executed asynchronously. You will receive a
   * MPV_EVENT_COMMAND_REPLY event. This event will also have an
   * error code set if running the command failed. For commands that
   * return data, the data is put into mpv_event_command.result.
   *
   * The only case when you do not receive an event is when the function call
   * itself fails. This happens only if parsing the command itself (or otherwise
   * validating it) fails, i.e. the return code of the API call is not 0 or
   * positive.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param reply_userdata the value mpv_event.reply_userdata of the reply will
   *                       be set to (see section about asynchronous calls)
   * @param args NULL-terminated list of strings (see mpv_command())
   * @return error code (if parsing or queuing the command fails)
    }

  mpv_command_async : function(var ctx:mpv_handle; reply_userdata:cuint64; args:PPchar):longint;cdecl;

  {*
   * Same as mpv_command_node(), but run it asynchronously. Basically, this
   * function is to mpv_command_node() what mpv_command_async() is to
   * mpv_command().
   *
   * See mpv_command_async() for details.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param reply_userdata the value mpv_event.reply_userdata of the reply will
   *                       be set to (see section about asynchronous calls)
   * @param args as in mpv_command_node()
   * @return error code (if parsing or queuing the command fails)
    }

  mpv_command_node_async : function(var ctx:mpv_handle; reply_userdata:uint64; args:mpv_node):cint;cdecl;

  {*
   * Signal to all async requests with the matching ID to abort. This affects
   * the following API calls:
   *
   *      mpv_command_async
   *      mpv_command_node_async
   *
   * All of these functions take a reply_userdata parameter. This API function
   * tells all requests with the matching reply_userdata value to try to return
   * as soon as possible. If there are multiple requests with matching ID, it
   * aborts all of them.
   *
   * This API function is mostly asynchronous itself. It will not wait until the
   * command is aborted. Instead, the command will terminate as usual, but with
   * some work not done. How this is signaled depends on the specific command (for
   * example, the "subprocess" command will indicate it by "killed_by_us" set to
   * true in the result). How long it takes also depends on the situation. The
   * aborting process is completely asynchronous.
   *
   * Not all commands may support this functionality. In this case, this function
   * will have no effect. The same is true if the request using the passed
   * reply_userdata has already terminated, has not been started yet, or was
   * never in use at all.
   *
   * You have to be careful of race conditions: the time during which the abort
   * request will be effective is _after_ e.g. mpv_command_async() has returned,
   * and before the command has signaled completion with MPV_EVENT_COMMAND_REPLY.
   *
   * @param reply_userdata ID of the request to be aborted (see above)
    }

  mpv_abort_async_command : procedure(var ctx:mpv_handle; reply_userdata:uint64);cdecl;

  {*
   * Set a property to a given value. Properties are essentially variables which
   * can be queried or set at runtime. For example, writing to the pause property
   * will actually pause or unpause playback.
   *
   * If the format doesn't match with the internal format of the property, access
   * usually will fail with MPV_ERROR_PROPERTY_FORMAT. In some cases, the data
   * is automatically converted and access succeeds. For example, MPV_FORMAT_INT64
   * is always converted to MPV_FORMAT_DOUBLE, and access using MPV_FORMAT_STRING
   * usually invokes a string parser. The same happens when calling this function
   * with MPV_FORMAT_NODE: the underlying format may be converted to another
   * type if possible.
   *
   * Using a format other than MPV_FORMAT_NODE is equivalent to constructing a
   * mpv_node with the given format and data, and passing the mpv_node to this
   * function. (Before API version 1.21, this was different.)
   *
   * Note: starting with mpv 0.21.0 (client API version 1.23), this can be used to
   *       set options in general. It even can be used before mpv_initialize()
   *       has been called. If called before mpv_initialize(), setting properties
   *       not backed by options will result in MPV_ERROR_PROPERTY_UNAVAILABLE.
   *       In some cases, properties and options still conflict. In these cases,
   *       mpv_set_property() accesses the options before mpv_initialize(), and
   *       the properties after mpv_initialize(). These conflicts will be removed
   *       in mpv 0.23.0. See mpv_set_option() for further remarks.
   *
   * @param name The property name. See input.rst for a list of properties.
   * @param format see enum mpv_format.
   * @param[in] data Option value.
   * @return error code
    }

  mpv_set_property : function(var ctx:mpv_handle; name:Pchar; format:mpv_format; data:pointer):longint;cdecl;

  {*
   * Convenience function to set a property to a string value.
   *
   * This is like calling mpv_set_property() with MPV_FORMAT_STRING.
    }

  mpv_set_property_string : function(var ctx:mpv_handle; const name:Pchar; const data:Pchar):longint;cdecl;

  {*
   * Convenience function to delete a property.
   *
   * This is equivalent to running the command "del [name]".
   *
   * @param name The property name. See input.rst for a list of properties.
   * @return error code
   *}

  mpv_del_property : function(var ctx:mpv_handle; const name:Pchar):longint;cdecl;

  {*
   * Set a property asynchronously. You will receive the result of the operation
   * as MPV_EVENT_SET_PROPERTY_REPLY event. The mpv_event.error field will contain
   * the result status of the operation. Otherwise, this function is similar to
   * mpv_set_property().
   *
   * Safe to be called from mpv render API threads.
   *
   * @param reply_userdata see section about asynchronous calls
   * @param name The property name.
   * @param format see enum mpv_format.
   * @param[in] data Option value. The value will be copied by the function. It
   *                 will never be modified by the client API.
   * @return error code if sending the request failed
    }

  mpv_set_property_async : function(var ctx:mpv_handle; reply_userdata:cuint64; name:Pchar; format:mpv_format; data:pointer):longint;cdecl;

  {*
   * Read the value of the given property.
   *
   * If the format doesn't match with the internal format of the property, access
   * usually will fail with MPV_ERROR_PROPERTY_FORMAT. In some cases, the data
   * is automatically converted and access succeeds. For example, MPV_FORMAT_INT64
   * is always converted to MPV_FORMAT_DOUBLE, and access using MPV_FORMAT_STRING
   * usually invokes a string formatter.
   *
   * @param name The property name.
   * @param format see enum mpv_format.
   * @param[out] data Pointer to the variable holding the option value. On
   *                  success, the variable will be set to a copy of the option
   *                  value. For formats that require dynamic memory allocation,
   *                  you can free the value with mpv_free() (strings) or
   *                  mpv_free_node_contents() (MPV_FORMAT_NODE).
   * @return error code
    }

  mpv_get_property : function(var ctx:mpv_handle; name:Pchar; format:mpv_format; data:pointer):longint;cdecl;

  {*
   * Return the value of the property with the given name as string. This is
   * equivalent to mpv_get_property() with MPV_FORMAT_STRING.
   *
   * See MPV_FORMAT_STRING for character encoding issues.
   *
   * On error, NULL is returned. Use mpv_get_property() if you want fine-grained
   * error reporting.
   *
   * @param name The property name.
   * @return Property value, or NULL if the property can't be retrieved. Free
   *         the string with mpv_free().
    }

  mpv_get_property_string : function(var ctx:mpv_handle; name:Pchar):Pchar;cdecl;

  {*
   * Return the property as "OSD" formatted string. This is the same as
   * mpv_get_property_string, but using MPV_FORMAT_OSD_STRING.
   *
   * @return Property value, or NULL if the property can't be retrieved. Free
   *         the string with mpv_free().
    }

  mpv_get_property_osd_string : function(var ctx:mpv_handle; name:Pchar):Pchar;cdecl;

  {*
   * Get a property asynchronously. You will receive the result of the operation
   * as well as the property data with the MPV_EVENT_GET_PROPERTY_REPLY event.
   * You should check the mpv_event.error field on the reply event.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param reply_userdata see section about asynchronous calls
   * @param name The property name.
   * @param format see enum mpv_format.
   * @return error code if sending the request failed
    }

  mpv_get_property_async : function(var ctx:mpv_handle; reply_userdata:cuint64; name:Pchar; format:mpv_format):longint;cdecl;

  {*
   * Get a notification whenever the given property changes. You will receive
   * updates as MPV_EVENT_PROPERTY_CHANGE. Note that this is not very precise:
   * for some properties, it may not send updates even if the property changed.
   * This depends on the property, and it's a valid feature request to ask for
   * better update handling of a specific property. (For some properties, like
   * ``clock``, which shows the wall clock, this mechanism doesn't make too
   * much sense anyway.)
   *
   * Property changes are coalesced: the change events are returned only once the
   * event queue becomes empty (e.g. mpv_wait_event() would block or return
   * MPV_EVENT_NONE), and then only one event per changed property is returned.
   *
   * You always get an initial change notification. This is meant to initialize
   * the user's state to the current value of the property.
   *
   * Normally, change events are sent only if the property value changes according
   * to the requested format. mpv_event_property will contain the property value
   * as data member.
   *
   * Warning: if a property is unavailable or retrieving it caused an error,
   *          MPV_FORMAT_NONE will be set in mpv_event_property, even if the
   *          format parameter was set to a different value. In this case, the
   *          mpv_event_property.data field is invalid.
   *
   * If the property is observed with the format parameter set to MPV_FORMAT_NONE,
   * you get low-level notifications whether the property _may_ have changed, and
   * the data member in mpv_event_property will be unset. With this mode, you
   * will have to determine yourself whether the property really changed. On the
   * other hand, this mechanism can be faster and uses less resources.
   *
   * Observing a property that doesn't exist is allowed. (Although it may still
   * cause some sporadic change events.)
   *
   * Keep in mind that you will get change notifications even if you change a
   * property yourself. Try to avoid endless feedback loops, which could happen
   * if you react to the change notifications triggered by your own change.
   *
   * Only the mpv_handle on which this was called will receive the property
   * change events, or can unobserve them.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param reply_userdata This will be used for the mpv_event.reply_userdata
   *                       field for the received MPV_EVENT_PROPERTY_CHANGE
   *                       events. (Also see section about asynchronous calls,
   *                       although this function is somewhat different from
   *                       actual asynchronous calls.)
   *                       If you have no use for this, pass 0.
   *                       Also see mpv_unobserve_property().
   * @param name The property name.
   * @param format see enum mpv_format. Can be MPV_FORMAT_NONE to omit values
   *               from the change events.
   * @return error code (usually fails only on OOM or unsupported format)
    }

  mpv_observe_property : function(var mpv:mpv_handle; reply_userdata:cuint64; name:Pchar; format:mpv_format):longint;cdecl;

  {*
   * Undo mpv_observe_property(). This will remove all observed properties for
   * which the given number was passed as reply_userdata to mpv_observe_property.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param registered_reply_userdata ID that was passed to mpv_observe_property
   * @return negative value is an error code, >=0 is number of removed properties
   *         on success (includes the case when 0 were removed)
    }

  mpv_unobserve_property : function(var mpv:mpv_handle; registered_reply_userdata:cuint64):longint;cdecl;

  type
    mpv_event_id =  Longint;

  const
  {*
       * Nothing happened. Happens on timeouts or sporadic wakeups.
        }

      MPV_EVENT_NONE = 0;

  {*
       * Happens when the player quits. The player enters a state where it tries
       * to disconnect all clients. Most requests to the player will fail, and
       * the client should react to this and quit with mpv_destroy() as soon as
       * possible.
        }

      MPV_EVENT_SHUTDOWN = 1;

  {*
       * See mpv_request_log_messages().
        }

      MPV_EVENT_LOG_MESSAGE = 2;

  {*
       * Reply to a mpv_get_property_async() request.
       * See also mpv_event and mpv_event_property.
        }

      MPV_EVENT_GET_PROPERTY_REPLY = 3;

  {*
       * Reply to a mpv_set_property_async() request.
       * (Unlike MPV_EVENT_GET_PROPERTY, mpv_event_property is not used.)
        }

      MPV_EVENT_SET_PROPERTY_REPLY = 4;

  {*
       * Reply to a mpv_command_async() or mpv_command_node_async() request.
       * See also mpv_event and mpv_event_command.
        }

      MPV_EVENT_COMMAND_REPLY = 5;

  {*
       * Notification before playback start of a file (before the file is loaded).
       * See also mpv_event and mpv_event_start_file.
        }

      MPV_EVENT_START_FILE = 6;

  {*
       * Notification after playback end (after the file was unloaded).
       * See also mpv_event and mpv_event_end_file.
        }

      MPV_EVENT_END_FILE = 7;

  {*
       * Notification when the file has been loaded (headers were read etc.), and
       * decoding starts.
        }

      MPV_EVENT_FILE_LOADED = 8;

  {*
       * Idle mode was entered. In this mode, no file is played, and the playback
       * core waits for new commands. (The command line player normally quits
       * instead of entering idle mode, unless --idle was specified. If mpv
       * was started with mpv_create(), idle mode is enabled by default.)
       *
       * @deprecated This is equivalent to using mpv_observe_property() on the
       *             "idle-active" property. The event is redundant, and might be
       *             removed in the far future. As a further warning, this event
       *             is not necessarily sent at the right point anymore (at the
       *             start of the program), while the property behaves correctly.
        }

      MPV_EVENT_IDLE = 11;

  {*
       * Sent every time after a video frame is displayed. Note that currently,
       * this will be sent in lower frequency if there is no video, or playback
       * is paused - but that will be removed in the future, and it will be
       * restricted to video frames only.
       *
       * @deprecated Use mpv_observe_property() with relevant properties instead
       *             (such as "playback-time").
        }

      MPV_EVENT_TICK = 14;

  {*
       * Triggered by the script-message input command. The command uses the
       * first argument of the command as client name (see mpv_client_name()) to
       * dispatch the message, and passes along all arguments starting from the
       * second argument as strings.
       * See also mpv_event and mpv_event_client_message.
        }

      MPV_EVENT_CLIENT_MESSAGE = 16;

  {*
       * Happens after video changed in some way. This can happen on resolution
       * changes, pixel format changes, or video filter changes. The event is
       * sent after the video filters and the VO are reconfigured. Applications
       * embedding a mpv window should listen to this event in order to resize
       * the window if needed.
       * Note that this event can happen sporadically, and you should check
       * yourself whether the video parameters really changed before doing
       * something expensive.
        }

      MPV_EVENT_VIDEO_RECONFIG = 17;

  {*
       * Similar to MPV_EVENT_VIDEO_RECONFIG. This is relatively uninteresting,
       * because there is no such thing as audio output embedding.
        }

      MPV_EVENT_AUDIO_RECONFIG = 18;

  {*
       * Happens when a seek was initiated. Playback stops. Usually it will
       * resume with MPV_EVENT_PLAYBACK_RESTART as soon as the seek is finished.
        }

      MPV_EVENT_SEEK = 20;

  {*
       * There was a discontinuity of some sort (like a seek), and playback
       * was reinitialized. Usually happens on start of playback and after
       * seeking. The main purpose is allowing the client to detect when a seek
       * request is finished.
        }

      MPV_EVENT_PLAYBACK_RESTART = 21;

  {*
       * Event sent due to mpv_observe_property().
       * See also mpv_event and mpv_event_property.
        }

      MPV_EVENT_PROPERTY_CHANGE = 22;

  {*
       * Happens if the internal per-mpv_handle ringbuffer overflows, and at
       * least 1 event had to be dropped. This can happen if the client doesn't
       * read the event queue quickly enough with mpv_wait_event(), or if the
       * client makes a very large number of asynchronous calls at once.
       *
       * Event delivery will continue normally once this event was returned
       * (this forces the client to empty the queue completely).
        }

      MPV_EVENT_QUEUE_OVERFLOW = 24;

  {*
       * Triggered if a hook handler was registered with mpv_hook_add(), and the
       * hook is invoked. If you receive this, you must handle it, and continue
       * the hook with mpv_hook_continue().
       * See also mpv_event and mpv_event_hook.
        }

      MPV_EVENT_HOOK = 25;
  { Internal note: adjust INTERNAL_EVENT_BASE when adding new events. }

  {*
   * Return a string describing the event. For unknown events, NULL is returned.
   *
   * Note that all events actually returned by the API will also yield a non-NULL
   * string with this function.
   *
   * @param event event ID, see see enum mpv_event_id
   * @return A static string giving a short symbolic name of the event. It
   *         consists of lower-case alphanumeric characters and can include "-"
   *         characters. This string is suitable for use in e.g. scripting
   *         interfaces.
   *         The string is completely static, i.e. doesn't need to be deallocated,
   *         and is valid forever.
    }

  var
    mpv_event_name : function(event:mpv_event_id):Pchar;cdecl;

  type
    Pmpv_event_property = ^mpv_event_property;
    mpv_event_property = record
        {*
         * Name of the property.
          }
        name : Pchar;
        {*
         * Format of the data field in the same struct. See enum mpv_format.
         * This is always the same format as the requested format, except when
         * the property could not be retrieved (unavailable, or an error happened),
         * in which case the format is MPV_FORMAT_NONE.
          }
        format : mpv_format;
        {*
         * Received property value. Depends on the format. This is like the
         * pointer argument passed to mpv_get_property().
         *
         * For example, for MPV_FORMAT_STRING you get the string with:
         *
         *    char *value = *(char **)(event_property->data);
         *
         * Note that this is set to NULL if retrieving the property failed (the
         * format will be MPV_FORMAT_NONE).
          }
        data : pointer;
      end;

  {*
   * Numeric log levels. The lower the number, the more important the message is.
   * MPV_LOG_LEVEL_NONE is never used when receiving messages. The string in
   * the comment after the value is the name of the log level as used for the
   * mpv_request_log_messages() function.
   * Unused numeric values are unused, but reserved for future use.
    }

    mpv_log_level = integer;
    const
      MPV_LOG_LEVEL_NONE = 0;   {/ "no"    - disable absolutely all messages }
      MPV_LOG_LEVEL_FATAL = 10; {/ "fatal" - critical/aborting errors }
      MPV_LOG_LEVEL_ERROR = 20; {/ "error" - simple errors }
      MPV_LOG_LEVEL_WARN = 30;  {/ "warn"  - possible problems }
      MPV_LOG_LEVEL_INFO = 40;  {/ "info"  - informational message }
      MPV_LOG_LEVEL_V = 50;     {/ "v"     - noisy informational message }
      MPV_LOG_LEVEL_DEBUG = 60; {/ "debug" - very noisy technical information }
      MPV_LOG_LEVEL_TRACE = 70; {/ "trace" - extremely noisy }

  type
    pmpv_event_log_message = ^_mpv_event_log_message;
    _mpv_event_log_message = record
       {*
        * The module prefix, identifies the sender of the message. As a special
        * case, if the message buffer overflows, this will be set to the string
        * "overflow" (which doesn't appear as prefix otherwise), and the text
        * field will contain an informative message.
         }
        prefix : Pchar;
        {*
         * The log level as string. See mpv_request_log_messages() for possible
         * values. The level "no" is never used here.
          }
        level : Pchar;
        {*
         * The log message. It consists of 1 line of text, and is terminated with
         * a newline character. (Before API version 1.6, it could contain multiple
         * or partial lines.)
          }
        text : Pchar;
        {*
         * The same contents as the level field, but as a numeric ID.
         * Since API version 1.6.
         }
        log_level : mpv_log_level;
      end;

    {/ Since API version 1.9. }
    mpv_end_file_reason = integer;
    const
      {*
       * The end of file was reached. Sometimes this may also happen on
       * incomplete or corrupted files, or if the network connection was
       * interrupted when playing a remote file. It also happens if the
       * playback range was restricted with --end or --frames or similar.
        }
      MPV_END_FILE_REASON_EOF = 0;
      {*
       * Playback was stopped by an external action (e.g. playlist controls).
        }
      MPV_END_FILE_REASON_STOP = 2;
      {*
       * Playback was stopped by the quit command or player shutdown.
        }
      MPV_END_FILE_REASON_QUIT = 3;
      {*
       * Some kind of error happened that lead to playback abort. Does not
       * necessarily happen on incomplete or broken files (in these cases, both
       * MPV_END_FILE_REASON_ERROR or MPV_END_FILE_REASON_EOF are possible).
       *
       * mpv_event_end_file.error will be set.
        }
      MPV_END_FILE_REASON_ERROR = 4;
      {*
       * The file was a playlist or similar. When the playlist is read, its
       * entries will be appended to the playlist after the entry of the current
       * file, the entry of the current file is removed, and a MPV_EVENT_END_FILE
       * event is sent with reason set to MPV_END_FILE_REASON_REDIRECT. Then
       * playback continues with the playlist contents.
       * Since API version 1.18.
        }
      MPV_END_FILE_REASON_REDIRECT = 5;

  type
    {/ Since API version 1.108. }
    Pmpv_event_start_file = ^_mpv_event_start_file;
    _mpv_event_start_file = record
        {*
         * Playlist entry ID of the file being loaded now.
          }
        playlist_entry_id : int64;
      end;

    Pmpv_event_end_file = ^_mpv_event_end_file;
    _mpv_event_end_file = record
        {*
         * Corresponds to the values in enum mpv_end_file_reason.
         *
         * Unknown values should be treated as unknown.
          }
        reason : integer; // mpv_end_file_reason;
        {*
         * If reason==MPV_END_FILE_REASON_ERROR, this contains a mpv error code
         * (one of MPV_ERROR_...) giving an approximate reason why playback
         * failed. In other cases, this field is 0 (no error).
         * Since API version 1.9.
          }
        error : integer;
        {*
         * Playlist entry ID of the file that was being played or attempted to be
         * played. This has the same value as the playlist_entry_id field in the
         * corresponding mpv_event_start_file event.
         * Since API version 1.108.
          }
        playlist_entry_id : int64;
        {*
         * If loading ended, because the playlist entry to be played was for example
         * a playlist, and the current playlist entry is replaced with a number of
         * other entries. This may happen at least with MPV_END_FILE_REASON_REDIRECT
         * (other event types may use this for similar but different purposes in the
         * future). In this case, playlist_insert_id will be set to the playlist
         * entry ID of the first inserted entry, and playlist_insert_num_entries to
         * the total number of inserted playlist entries. Note this in this specific
         * case, the ID of the last inserted entry is playlist_insert_id+num-1.
         * Beware that depending on circumstances, you may observe the new playlist
         * entries before seeing the event (e.g. reading the "playlist" property or
         * getting a property change notification before receiving the event).
         * Since API version 1.108.
          }
        playlist_insert_id : int64;
        {*
         * See playlist_insert_id. Only non-0 if playlist_insert_id is valid. Never
         * negative.
         * Since API version 1.108.
          }
        playlist_insert_num_entries : integer;
      end;
  {*
       * Arbitrary arguments chosen by the sender of the message. If num_args > 0,
       * you can access args[0] through args[num_args - 1] (inclusive). What
       * these arguments mean is up to the sender and receiver.
       * None of the valid items are NULL.
        }

    Pmpv_event_client_message = ^_mpv_event_client_message;
    _mpv_event_client_message = record
        num_args : integer;
        args : PPchar;
      end;

    Pmpv_event_hook = ^_mpv_event_hook;
    _mpv_event_hook = record
        {*
         * The hook name as passed to mpv_hook_add().
          }
        name : Pchar;
        {*
         * Internal ID that must be passed to mpv_hook_continue().
          }
        id : uint64;
      end;

  { Since API version 1.102. }
    Pmpv_event_command = ^mpv_event_command;
    mpv_event_command = record
        {*
         * Result data of the command. Note that success/failure is signaled
         * separately via mpv_event.error. This field is only for result data
         * in case of success. Most commands leave it at MPV_FORMAT_NONE. Set
         * to MPV_FORMAT_NONE on failure.
          }
        result : mpv_node;
      end;

    Pmpv_event = ^mpv_event;
    mpv_event = record
        {*
         * One of mpv_event. Keep in mind that later ABI compatible releases might
         * add new event types. These should be ignored by the API user.
          }
        event_id : mpv_event_id;
        {*
         * This is mainly used for events that are replies to (asynchronous)
         * requests. It contains a status code, which is >= 0 on success, or < 0
         * on error (a mpv_error value). Usually, this will be set if an
         * asynchronous request fails.
         * Used for:
         *  MPV_EVENT_GET_PROPERTY_REPLY
         *  MPV_EVENT_SET_PROPERTY_REPLY
         *  MPV_EVENT_COMMAND_REPLY
          }
        error : integer;
        {*
         * If the event is in reply to a request (made with this API and this
         * API handle), this is set to the reply_userdata parameter of the request
         * call. Otherwise, this field is 0.
         * Used for:
         *  MPV_EVENT_GET_PROPERTY_REPLY
         *  MPV_EVENT_SET_PROPERTY_REPLY
         *  MPV_EVENT_COMMAND_REPLY
         *  MPV_EVENT_PROPERTY_CHANGE
         *  MPV_EVENT_HOOK
          }
        reply_userdata : uint64;
        {*
         * The meaning and contents of the data member depend on the event_id:
         *  MPV_EVENT_GET_PROPERTY_REPLY:     mpv_event_property*
         *  MPV_EVENT_PROPERTY_CHANGE:        mpv_event_property*
         *  MPV_EVENT_LOG_MESSAGE:            mpv_event_log_message*
         *  MPV_EVENT_CLIENT_MESSAGE:         mpv_event_client_message*
         *  MPV_EVENT_START_FILE:             mpv_event_start_file* (since v1.108)
         *  MPV_EVENT_END_FILE:               mpv_event_end_file*
         *  MPV_EVENT_HOOK:                   mpv_event_hook*
         *  MPV_EVENT_COMMAND_REPLY*          mpv_event_command*
         *  other: NULL
         *
         * Note: future enhancements might add new event structs for existing or new
         *       event types.
          }
        data : pointer;
      end;

  {*
   * Convert the given src event to a mpv_node, and set *dst to the result. *dst
   * is set to a MPV_FORMAT_NODE_MAP, with fields for corresponding mpv_event and
   * mpv_event.data/mpv_event_* fields.
   *
   * The exact details are not completely documented out of laziness. A start
   * is located in the "Events" section of the manpage.
   *
   * *dst may point to newly allocated memory, or pointers in mpv_event. You must
   * copy the entire mpv_node if you want to reference it after mpv_event becomes
   * invalid (such as making a new mpv_wait_event() call, or destroying the
   * mpv_handle from which it was returned). Call mpv_free_node_contents() to free
   * any memory allocations made by this API function.
   *
   * Safe to be called from mpv render API threads.
   *
   * @param dst Target. This is not read and fully overwritten. Must be released
   *            with mpv_free_node_contents(). Do not write to pointers returned
   *            by it. (On error, this may be left as an empty node.)
   * @param src The source event. Not modified (it's not const due to the author's
   *            prejudice of the C version of const).
   * @return error code (MPV_ERROR_NOMEM only, if at all)
    }

  var
    mpv_event_to_node : function(dst:Pmpv_node; src:Pmpv_event):integer;cdecl;

  {*
   * Enable or disable the given event.
   *
   * Some events are enabled by default. Some events can't be disabled.
   *
   * (Informational note: currently, all events are enabled by default, except
   *  MPV_EVENT_TICK.)
   *
   * Safe to be called from mpv render API threads.
   *
   * @param event See enum mpv_event_id.
   * @param enable 1 to enable receiving this event, 0 to disable it.
   * @return error code
    }

  mpv_request_event : function(var ctx:mpv_handle; event:mpv_event_id; enable:longint):longint;cdecl;

  {*
   * Enable or disable receiving of log messages. These are the messages the
   * command line player prints to the terminal. This call sets the minimum
   * required log level for a message to be received with MPV_EVENT_LOG_MESSAGE.
   *
   * @param min_level Minimal log level as string. Valid log levels:
   *                      no fatal error warn info v debug trace
   *                  The value "no" disables all messages. This is the default.
   *                  An exception is the value "terminal-default", which uses the
   *                  log level as set by the "--msg-level" option. This works
   *                  even if the terminal is disabled. (Since API version 1.19.)
   *                  Also see mpv_log_level.
   * @return error code
    }

  mpv_request_log_messages : function(var ctx:mpv_handle; min_level:Pchar):longint;cdecl;

  {*
   * Wait for the next event, or until the timeout expires, or if another thread
   * makes a call to mpv_wakeup(). Passing 0 as timeout will never wait, and
   * is suitable for polling.
   *
   * The internal event queue has a limited size (per client handle). If you
   * don't empty the event queue quickly enough with mpv_wait_event(), it will
   * overflow and silently discard further events. If this happens, making
   * asynchronous requests will fail as well (with MPV_ERROR_EVENT_QUEUE_FULL).
   *
   * Only one thread is allowed to call this on the same mpv_handle at a time.
   * The API won't complain if more than one thread calls this, but it will cause
   * race conditions in the client when accessing the shared mpv_event struct.
   * Note that most other API functions are not restricted by this, and no API
   * function internally calls mpv_wait_event(). Additionally, concurrent calls
   * to different mpv_handles are always safe.
   *
   * As long as the timeout is 0, this is safe to be called from mpv render API
   * threads.
   *
   * @param timeout Timeout in seconds, after which the function returns even if
   *                no event was received. A MPV_EVENT_NONE is returned on
   *                timeout. A value of 0 will disable waiting. Negative values
   *                will wait with an infinite timeout.
   * @return A struct containing the event ID and other data. The pointer (and
   *         fields in the struct) stay valid until the next mpv_wait_event()
   *         call, or until the mpv_handle is destroyed. You must not write to
   *         the struct, and all memory referenced by it will be automatically
   *         released by the API on the next mpv_wait_event() call, or when the
   *         context is destroyed. The return value is never NULL.
    }

  mpv_wait_event : function(var ctx:mpv_handle; timeout:double):Pmpv_event;cdecl;

  {*
   * Interrupt the current mpv_wait_event() call. This will wake up the thread
   * currently waiting in mpv_wait_event(). If no thread is waiting, the next
   * mpv_wait_event() call will return immediately (this is to avoid lost
   * wakeups).
   *
   * mpv_wait_event() will receive a MPV_EVENT_NONE if it's woken up due to
   * this call. But note that this dummy event might be skipped if there are
   * already other events queued. All what counts is that the waiting thread
   * is woken up at all.
   *
   * Safe to be called from mpv render API threads.
    }

  mpv_wakeup : procedure(var ctx:mpv_handle);cdecl;

  {*
   * Set a custom function that should be called when there are new events. Use
   * this if blocking in mpv_wait_event() to wait for new events is not feasible.
   *
   * Keep in mind that the callback will be called from foreign threads. You
   * must not make any assumptions of the environment, and you must return as
   * soon as possible (i.e. no long blocking waits). Exiting the callback through
   * any other means than a normal return is forbidden (no throwing exceptions,
   * no longjmp() calls). You must not change any local thread state (such as
   * the C floating point environment).
   *
   * You are not allowed to call any client API functions inside of the callback.
   * In particular, you should not do any processing in the callback, but wake up
   * another thread that does all the work. The callback is meant strictly for
   * notification only, and is called from arbitrary core parts of the player,
   * that make no considerations for reentrant API use or allowing the callee to
   * spend a lot of time doing other things. Keep in mind that it's also possible
   * that the callback is called from a thread while a mpv API function is called
   * (i.e. it can be reentrant).
   *
   * In general, the client API expects you to call mpv_wait_event() to receive
   * notifications, and the wakeup callback is merely a helper utility to make
   * this easier in certain situations. Note that it's possible that there's
   * only one wakeup callback invocation for multiple events. You should call
   * mpv_wait_event() with no timeout until MPV_EVENT_NONE is reached, at which
   * point the event queue is empty.
   *
   * If you actually want to do processing in a callback, spawn a thread that
   * does nothing but call mpv_wait_event() in a loop and dispatches the result
   * to a callback.
   *
   * Only one wakeup callback can be set.
   *
   * @param cb function that should be called if a wakeup is required
   * @param d arbitrary userdata passed to cb
    }

type

  mpv_callback = procedure(d:pointer);cdecl;

var

  mpv_set_wakeup_callback : procedure(var ctx:mpv_handle; cb:mpv_callback; d:pointer);cdecl;

  {*
   * Block until all asynchronous requests are done. This affects functions like
   * mpv_command_async(), which return immediately and return their result as
   * events.
   *
   * This is a helper, and somewhat equivalent to calling mpv_wait_event() in a
   * loop until all known asynchronous requests have sent their reply as event,
   * except that the event queue is not emptied.
   *
   * In case you called mpv_suspend() before, this will also forcibly reset the
   * suspend counter of the given handle.
    }

  mpv_wait_async_requests : procedure(var ctx:mpv_handle);cdecl;

  {*
   * A hook is like a synchronous event that blocks the player. You register
   * a hook handler with this function. You will get an event, which you need
   * to handle, and once things are ready, you can let the player continue with
   * mpv_hook_continue().
   *
   * Currently, hooks can't be removed explicitly. But they will be implicitly
   * removed if the mpv_handle it was registered with is destroyed. This also
   * continues the hook if it was being handled by the destroyed mpv_handle (but
   * this should be avoided, as it might mess up order of hook execution).
   *
   * Hook handlers are ordered globally by priority and order of registration.
   * Handlers for the same hook with same priority are invoked in order of
   * registration (the handler registered first is run first). Handlers with
   * lower priority are run first (which seems backward).
   *
   * See the "Hooks" section in the manpage to see which hooks are currently
   * defined.
   *
   * Some hooks might be reentrant (so you get multiple MPV_EVENT_HOOK for the
   * same hook). If this can happen for a specific hook type, it will be
   * explicitly documented in the manpage.
   *
   * Only the mpv_handle on which this was called will receive the hook events,
   * or can "continue" them.
   *
   * @param reply_userdata This will be used for the mpv_event.reply_userdata
   *                       field for the received MPV_EVENT_HOOK events.
   *                       If you have no use for this, pass 0.
   * @param name The hook name. This should be one of the documented names. But
   *             if the name is unknown, the hook event will simply be never
   *             raised.
   * @param priority See remarks above. Use 0 as a neutral default.
   * @return error code (usually fails only on OOM)
    }

  mpv_hook_add : function(var ctx:mpv_handle; reply_userdata:uint64; const name:Pchar; priority:integer):integer;cdecl;

  {*
   * Respond to a MPV_EVENT_HOOK event. You must call this after you have handled
   * the event. There is no way to "cancel" or "stop" the hook.
   *
   * Calling this will will typically unblock the player for whatever the hook
   * is responsible for (e.g. for the "on_load" hook it lets it continue
   * playback).
   *
   * It is explicitly undefined behavior to call this more than once for each
   * MPV_EVENT_HOOK, to pass an incorrect ID, or to call this on a mpv_handle
   * different from the one that registered the handler and received the event.
   *
   * @param id This must be the value of the mpv_event_hook.id field for the
   *           corresponding MPV_EVENT_HOOK.
   * @return error code
    }

  mpv_hook_continue : function(var ctx:mpv_handle; id:uint64):integer;cdecl;

  {*
   * Return a UNIX file descriptor referring to the read end of a pipe. This
   * pipe can be used to wake up a poll() based processing loop. The purpose of
   * this function is very similar to mpv_set_wakeup_callback(), and provides
   * a primitive mechanism to handle coordinating a foreign event loop and the
   * libmpv event loop. The pipe is non-blocking. It's closed when the mpv_handle
   * is destroyed. This function always returns the same value (on success).
   *
   * This is in fact implemented using the same underlying code as for
   * mpv_set_wakeup_callback() (though they don't conflict), and it is as if each
   * callback invocation writes a single 0 byte to the pipe. When the pipe
   * becomes readable, the code calling poll() (or select()) on the pipe should
   * read all contents of the pipe and then call mpv_wait_event(c, 0) until
   * no new events are returned. The pipe contents do not matter and can just
   * be discarded. There is not necessarily one byte per readable event in the
   * pipe. For example, the pipes are non-blocking, and mpv won't block if the
   * pipe is full. Pipes are normally limited to 4096 bytes, so if there are
   * more than 4096 events, the number of readable bytes can not equal the number
   * of events queued. Also, it's possible that mpv does not write to the pipe
   * once it's guaranteed that the client was already signaled. See the example
   * below how to do it correctly.
   *
   * Example:
   *
   *  int pipefd = mpv_get_wakeup_pipe(mpv);
   *  if (pipefd < 0)
   *      error();
   *  while (1) 
   *      struct pollfd pfds[1] = 
   *           .fd = pipefd, .events = POLLIN ,
   *      ;
   *      // Wait until there are possibly new mpv events.
   *      poll(pfds, 1, -1);
   *      if (pfds[0].revents & POLLIN) 
   *          // Empty the pipe. Doing this before calling mpv_wait_event()
   *          // ensures that no wakeups are missed. It's not so important to
   *          // make sure the pipe is really empty (it will just cause some
   *          // additional wakeups in unlikely corner cases).
   *          char unused[256];
   *          read(pipefd, unused, sizeof(unused));
   *          while (1) 
   *              mpv_event *ev = mpv_wait_event(mpv, 0);
   *              // If MPV_EVENT_NONE is received, the event queue is empty.
   *              if (ev->event_id == MPV_EVENT_NONE)
   *                  break;
   *              // Process the event.
   *              ...
   *          
   *      
   *  
   *
   * @deprecated this function will be removed in the future. If you need this
   *             functionality, use mpv_set_wakeup_callback(), create a pipe
   *             manually, and call write() on your pipe in the callback.
   *
   * @return A UNIX FD of the read end of the wakeup pipe, or -1 on error.
   *         On MS Windows/MinGW, this will always return -1.
    }

  mpv_get_wakeup_pipe : function(var ctx:mpv_handle):integer;cdecl;

// -----------------------------------------------------------------------------

procedure Free_libMPV;
function Load_libMPV(const AFileName: String = ''): Integer;

function IsLibMPV_Loaded: Boolean;
function IsLibMPV_Installed(const AFileName: String = ''): Integer;

var
  hLibMPV: TLibHandle;

// -----------------------------------------------------------------------------

implementation

uses
  SysUtils, dynlibs;

{$IFDEF UNIX}
function setlocale(category: cint; locale: pchar): pchar; cdecl; external 'c' name 'setlocale';
{$ENDIF}

// -----------------------------------------------------------------------------

function LIBMPV_MAKE_VERSION(major, minor: Integer): Integer;
begin
  Result := ((major shl 16) or minor) or 0;
end;

// -----------------------------------------------------------------------------

function LIBMPV_CLIENT_API_VERSION: Integer;
begin
  Result := LIBMPV_MAKE_VERSION(2, 2);
end;

// -----------------------------------------------------------------------------

function TryLoadLibMPV: TLibHandle;
var
  i: Byte;
begin
  Result := dynlibs.NilHandle;

  for i := Low(LIBMPV_DLL_VER) to High(LIBMPV_DLL_VER) do
  begin
    {$IFDEF WINDOWS}
    Result := LoadLibrary(LIBMPV_DLL_NAME + LIBMPV_DLL_VER[i] + '.dll');
    {$ELSE}
    {$IFDEF DARWIN}
    Result := LoadLibrary(LIBMPV_DLL_NAME + LIBMPV_DLL_VER[i] + '.dylib');
    {$ELSE}
    Result := LoadLibrary(LIBMPV_DLL_NAME + '.so' + LIBMPV_DLL_VER[i]);
    {$ENDIF DARWIN}
    {$ENDIF WINDOWS}

    if Result <> dynlibs.NilHandle then
      Break;
  end;
end;

// -----------------------------------------------------------------------------

procedure Free_libMPV;
begin
  if (hLibMPV <> dynlibs.NilHandle) and UnloadLibrary(hLibMPV) then
    hLibMPV := dynlibs.NilHandle;

  mpv_client_api_version := NIL;
  mpv_error_string := NIL;
  mpv_free := NIL;
  mpv_client_name := NIL;
  mpv_client_id := NIL;
  mpv_create := NIL;
  mpv_initialize := NIL;
  mpv_destroy := NIL;
  mpv_terminate_destroy := NIL;
  mpv_create_client := NIL;
  mpv_create_weak_client := NIL;
  mpv_load_config_file := NIL;
  mpv_get_time_us := NIL;
  mpv_free_node_contents := NIL;
  mpv_set_option := NIL;
  mpv_set_option_string := NIL;
  mpv_command := NIL;
  mpv_command_node := NIL;
  mpv_command_ret := NIL;
  mpv_command_string := NIL;
  mpv_command_async := NIL;
  mpv_command_node_async := NIL;
  mpv_abort_async_command := NIL;
  mpv_set_property := NIL;
  mpv_set_property_string := NIL;
  mpv_set_property_async := NIL;
  mpv_get_property := NIL;
  mpv_get_property_string := NIL;
  mpv_get_property_osd_string := NIL;
  mpv_get_property_async := NIL;
  mpv_observe_property := NIL;
  mpv_unobserve_property := NIL;
  mpv_event_name := NIL;
  mpv_event_to_node := NIL;
  mpv_request_event := NIL;
  mpv_request_log_messages := NIL;
  mpv_wait_event := NIL;
  mpv_wakeup := NIL;
  mpv_set_wakeup_callback := NIL;
  mpv_wait_async_requests := NIL;
  mpv_hook_add := NIL;
  mpv_hook_continue := NIL;
  mpv_get_wakeup_pipe := NIL;
end;

// -----------------------------------------------------------------------------

function Load_libMPV(const AFileName: String = ''): Integer;
begin
  if IsLibMPV_Loaded then Exit(MPV_ERROR_SUCCESS);

  Result := MPV_ERROR_GENERIC;

  if AFileName.IsEmpty then
    hLibMPV := TryLoadLibMPV
  else
    hLibMPV := LoadLibrary(AFileName);

  if (hLibMPV = dynlibs.NilHandle) then Exit;

  Pointer(mpv_client_api_version) := GetProcAddress(hLibMPV,'mpv_client_api_version');
  Pointer(mpv_error_string) := GetProcAddress(hLibMPV,'mpv_error_string');
  Pointer(mpv_free) := GetProcAddress(hLibMPV,'mpv_free');
  Pointer(mpv_client_name) := GetProcAddress(hLibMPV,'mpv_client_name');
  Pointer(mpv_client_id) := GetProcAddress(hLibMPV,'mpv_client_id');
  Pointer(mpv_create) := GetProcAddress(hLibMPV,'mpv_create');
  Pointer(mpv_initialize) := GetProcAddress(hLibMPV,'mpv_initialize');
  Pointer(mpv_destroy) := GetProcAddress(hLibMPV,'mpv_destroy');
  Pointer(mpv_terminate_destroy) := GetProcAddress(hLibMPV,'mpv_terminate_destroy');
  Pointer(mpv_create_client) := GetProcAddress(hLibMPV,'mpv_create_client');
  Pointer(mpv_create_weak_client) := GetProcAddress(hLibMPV,'mpv_create_weak_client');
  Pointer(mpv_load_config_file) := GetProcAddress(hLibMPV,'mpv_load_config_file');
  Pointer(mpv_get_time_us) := GetProcAddress(hLibMPV,'mpv_get_time_us');
  Pointer(mpv_free_node_contents) := GetProcAddress(hLibMPV,'mpv_free_node_contents');
  Pointer(mpv_set_option) := GetProcAddress(hLibMPV,'mpv_set_option');
  Pointer(mpv_set_option_string) := GetProcAddress(hLibMPV,'mpv_set_option_string');
  Pointer(mpv_command) := GetProcAddress(hLibMPV,'mpv_command');
  Pointer(mpv_command_node) := GetProcAddress(hLibMPV,'mpv_command_node');
  Pointer(mpv_command_ret) := GetProcAddress(hLibMPV,'mpv_command_ret');
  Pointer(mpv_command_string) := GetProcAddress(hLibMPV,'mpv_command_string');
  Pointer(mpv_command_async) := GetProcAddress(hLibMPV,'mpv_command_async');
  Pointer(mpv_command_node_async) := GetProcAddress(hLibMPV,'mpv_command_node_async');
  Pointer(mpv_abort_async_command) := GetProcAddress(hLibMPV,'mpv_abort_async_command');
  Pointer(mpv_set_property) := GetProcAddress(hLibMPV,'mpv_set_property');
  Pointer(mpv_set_property_string) := GetProcAddress(hLibMPV,'mpv_set_property_string');
  Pointer(mpv_set_property_async) := GetProcAddress(hLibMPV,'mpv_set_property_async');
  Pointer(mpv_get_property) := GetProcAddress(hLibMPV,'mpv_get_property');
  Pointer(mpv_get_property_string) := GetProcAddress(hLibMPV,'mpv_get_property_string');
  Pointer(mpv_get_property_osd_string) := GetProcAddress(hLibMPV,'mpv_get_property_osd_string');
  Pointer(mpv_get_property_async) := GetProcAddress(hLibMPV,'mpv_get_property_async');
  Pointer(mpv_observe_property) := GetProcAddress(hLibMPV,'mpv_observe_property');
  Pointer(mpv_unobserve_property) := GetProcAddress(hLibMPV,'mpv_unobserve_property');
  Pointer(mpv_event_name) := GetProcAddress(hLibMPV,'mpv_event_name');
  Pointer(mpv_event_to_node) := GetProcAddress(hLibMPV,'mpv_event_to_node');
  Pointer(mpv_request_event) := GetProcAddress(hLibMPV,'mpv_request_event');
  Pointer(mpv_request_log_messages) := GetProcAddress(hLibMPV,'mpv_request_log_messages');
  Pointer(mpv_wait_event) := GetProcAddress(hLibMPV,'mpv_wait_event');
  Pointer(mpv_wakeup) := GetProcAddress(hLibMPV,'mpv_wakeup');
  Pointer(mpv_set_wakeup_callback) := GetProcAddress(hLibMPV,'mpv_set_wakeup_callback');
  Pointer(mpv_wait_async_requests) := GetProcAddress(hLibMPV,'mpv_wait_async_requests');
  Pointer(mpv_hook_add) := GetProcAddress(hLibMPV,'mpv_hook_add');
  Pointer(mpv_hook_continue) := GetProcAddress(hLibMPV,'mpv_hook_continue');
  Pointer(mpv_get_wakeup_pipe) := GetProcAddress(hLibMPV,'mpv_get_wakeup_pipe');

  if not Assigned(mpv_client_api_version) or
     not Assigned(mpv_error_string) or
     not Assigned(mpv_free) or
     not Assigned(mpv_client_name) or
     not Assigned(mpv_client_id) or
     not Assigned(mpv_create) or
     not Assigned(mpv_initialize) or
     not Assigned(mpv_destroy) or
     not Assigned(mpv_terminate_destroy) or
     not Assigned(mpv_create_weak_client) or
     not Assigned(mpv_load_config_file) or
     not Assigned(mpv_get_time_us) or
     not Assigned(mpv_free_node_contents) or
     not Assigned(mpv_set_option) or
     not Assigned(mpv_set_option_string) or
     not Assigned(mpv_command) or
     not Assigned(mpv_command_node) or
     not Assigned(mpv_command_ret) or
     not Assigned(mpv_command_string) or
     not Assigned(mpv_command_async) or
     not Assigned(mpv_command_node_async) or
     not Assigned(mpv_abort_async_command) or
     not Assigned(mpv_set_property) or
     not Assigned(mpv_set_property_string) or
     not Assigned(mpv_set_property_async) or
     not Assigned(mpv_get_property) or
     not Assigned(mpv_get_property_string) or
     not Assigned(mpv_get_property_osd_string) or
     not Assigned(mpv_get_property_async) or
     not Assigned(mpv_observe_property) or
     not Assigned(mpv_unobserve_property) or
     not Assigned(mpv_event_name) or
     not Assigned(mpv_event_to_node) or
     not Assigned(mpv_request_event) or
     not Assigned(mpv_request_log_messages) or
     not Assigned(mpv_wait_event) or
     not Assigned(mpv_wakeup) or
     not Assigned(mpv_set_wakeup_callback) or
     not Assigned(mpv_wait_async_requests) or
     not Assigned(mpv_hook_add) or
     not Assigned(mpv_hook_continue) or
     not Assigned(mpv_get_wakeup_pipe) then
  begin
    Free_libMPV;
    Exit(MPV_ERROR_UNSUPPORTED);
  end;

  Result := MPV_ERROR_SUCCESS;
end;

// -----------------------------------------------------------------------------

function IsLibMPV_Loaded: Boolean;
begin
  Result := hLibMPV <> dynlibs.NilHandle;
end;

// -----------------------------------------------------------------------------

function IsLibMPV_Installed(const AFileName: String = ''): Integer;
var
  FHandle: Pmpv_handle;
begin
  Result := MPV_ERROR_GENERIC;

  if IsLibMPV_Loaded then
    Exit(MPV_ERROR_SUCCESS);

  if Load_libMPV(AFileName) = MPV_ERROR_SUCCESS then
    try
      FHandle := mpv_create();
      if not Assigned(FHandle) then
        Exit(MPV_ERROR_UNSUPPORTED);

      try
        if mpv_initialize(FHandle^) <> MPV_ERROR_SUCCESS then
          Exit(MPV_ERROR_UNINITIALIZED);
      finally
        mpv_terminate_destroy(FHandle^);
      end;

      Result := MPV_ERROR_SUCCESS;
    finally
      FHandle := NIL;
      Free_libMPV;
    end;
end;

// -----------------------------------------------------------------------------

initialization
  {$IFDEF UNIX}
  setlocale(1, 'C');
  {$ENDIF}
  hLibMPV := dynlibs.NilHandle;

// -----------------------------------------------------------------------------

finalization

// -----------------------------------------------------------------------------

end.