GstSyncServer: GStreamer Sync Server Reference Manual

GstSyncServer

GstSyncServer — Provides a server object to publish information that clients on a network can use to play a stream in a synchronised manner.

Functions

GstSyncServer *	gst_sync_server_new ()
gboolean	gst_sync_server_start ()
void	gst_sync_server_stop ()
void	gst_sync_server_set_stopped ()
void	gst_sync_server_set_paused ()
GVariant *	gst_sync_server_playlist_new ()
GVariant *	gst_sync_server_playlist_set_tracks ()
GVariant *	gst_sync_server_playlist_set_current_track ()
void	gst_sync_server_playlist_get_tracks ()
void	gst_sync_server_playlist_free_tracks ()
guint64	gst_sync_server_playlist_get_current_track ()

Properties

gchar *	control-address	Read / Write
gint	control-port	Read / Write
GObject *	control-server	Read / Write
guint64	latency	Read / Write
GVariant *	playlist	Read / Write
guint64	stream-start-delay	Read / Write

Signals

void	end-of-playlist	Run First
void	end-of-stream	Run First

Types and Values

GstSyncServer

Object Hierarchy

    GObject
    ╰── GstSyncServer

Description

The GstSyncServer object provides API to start a server on one device on a network that other devices (using GstSyncClient) can communicate with to play a stream such that all devices are playing the same stream at the same time.

It also provides API to control these clients and perform tasks such as switching the currently playing stream, pausing/unpausing, etc.

GstSyncServer itself does not implement the network transport for controlling the client, but defers that to an object that implements the GstSyncControlServer interface. A default TCP-based implementation is provided with this library, however.

The stream(s) to play are configured using the “playlist” property, which takes a GVariant that can be constructed using gst_sync_server_playlist_new() and manipulated by related functions.

Functions

gst_sync_server_new ()

GstSyncServer *
gst_sync_server_new (const gchar *control_addr,
                     gint control_port);

Creates a new GstSyncServer object that will listen on the given network address/port pair once started.

Parameters

control_addr	The network address that the server should listen on
control_port	The network port that the server should listen on

Returns

A new GstSyncServer object.

[transfer full]

gst_sync_server_start ()

gboolean
gst_sync_server_start (GstSyncServer *server,
                       GError **error);

Starts the GstSyncServer so that clients can connect and start synchronised playback.

Parameters

server	The GstSyncServer object
error	If non-NULL, will be set to the appropriate GError if starting the server fails.

Returns

TRUE on success, and FALSE if the server could not be started.

gst_sync_server_stop ()

void
gst_sync_server_stop (GstSyncServer *server);

Disconnects all existing clients and stops listening for new clients.

Parameters

server

The GstSyncServer object

gst_sync_server_set_stopped ()

void
gst_sync_server_set_stopped (GstSyncServer *server,
                             gboolean stopped);

Stops or restarts playback of the current stream on all connected clients.

Parameters

server	The GstSyncServer object
stopped	Whether the stream should be stopped (or restarted)

gst_sync_server_set_paused ()

void
gst_sync_server_set_paused (GstSyncServer *server,
                            gboolean paused);

Pauses or unpauses playback of the current stream on all connected clients.

Parameters

server	The GstSyncServer object
paused	Whether the stream should be paused or unpaused

gst_sync_server_playlist_new ()

GVariant *
gst_sync_server_playlist_new (gchar **uris,
                              guint64 *durations,
                              guint64 n_tracks,
                              guint64 current_track);

Creates a playlist object from the given uris, durations and current track.

Parameters

uris	A list of string URIs representing the playlist.	[array length=n_tracks]
durations	A list of durations corresponding to each URI (set to GST_CLOCK_TIME_NONE if unknown).	[array length=n_tracks]
n_tracks	The number of tracks in `uris` and `durations` .
current_track	The current track to play

Returns

The playlist as a GVariant

gst_sync_server_playlist_set_tracks ()

GVariant *
gst_sync_server_playlist_set_tracks (GVariant *playlist,
                                     gchar **uris,
                                     guint64 *durations,
                                     guint64 n_tracks);

Changes the track list in the given playlist and returns a new playlist.

Parameters

playlist	The playlist.	[transfer full]
uris	A list of string URIs representing the playlist.	[array length=n_tracks]
durations	A list of durations corresponding to each URI (set to GST_CLOCK_TIME_NONE if unknown).	[array length=n_tracks]
n_tracks	The number of tracks in `uris` and `durations` .

Returns

The new playlist as a GVariant.

[transfer full]

gst_sync_server_playlist_set_current_track ()

GVariant *
gst_sync_server_playlist_set_current_track
                               (GVariant *playlist,
                                guint64 current_track);

Changes the currently playing track in the given playlist and returns a new playlist.

Parameters

playlist	The playlist.	[transfer full]
current_track	The current track to play

Returns

The new playlist as a GVariant.

[transfer full]

gst_sync_server_playlist_get_tracks ()

void
gst_sync_server_playlist_get_tracks (GVariant *playlist,
                                     gchar ***uris,
                                     guint64 **durations,
                                     guint64 *n_tracks);

Returns the set of tracks and their corresponding durations, if available. Use gst_sync_server_playlist_free_tracks() to free uris and durations .

Parameters

playlist	The playlist
uris	A list of string URIs representing the playlist.	[out callee-allocates][array length=n_tracks]
durations	A list of durations corresponding to each URI in `uris` (set to GST_CLOCK_TIME_NONE if duration for a stream is unknown).	[out callee-allocates][array length=n_tracks]
n_tracks	The number of tracks returned in `uris` and `durations` .	[out caller-allocates]

gst_sync_server_playlist_free_tracks ()

void
gst_sync_server_playlist_free_tracks (gchar **uris,
                                      guint64 *durations,
                                      guint64 n_tracks);

Frees the URIs and durations (allocated by gst_sync_server_playlist_get_tracks().

Parameters

uris	A list of string URIs representing the playlist.	[array length=n_tracks]
durations	A list of durations corresponding to each URI.	[array length=n_tracks]
n_tracks	The number of tracks in `uris` and `durations` .

gst_sync_server_playlist_get_current_track ()

guint64
gst_sync_server_playlist_get_current_track
                               (GVariant *playlist);

Parameters

playlist

The playlist

Returns

The currently streaming track

Types and Values

GstSyncServer

typedef struct _GstSyncServer GstSyncServer;

Property Details

The `“control-address”` property

  “control-address”          gchar *

The network address for the control server to listen on.

Flags: Read / Write

Default value: NULL

The `“control-port”` property

  “control-port”             gint

The network port for the control server to listen on.

Flags: Read / Write

Allowed values: [0,65535]

Default value: 0

The `“control-server”` property

  “control-server”           GObject *

The implementation of the control protocol that should be used to communicate with clients. This object must implement the GstSyncControlServer interface. If set to NULL, a built-in TCP implementation is used.

Flags: Read / Write

The `“latency”` property

  “latency”                  guint64

The pipeline latency that clients should use. This should be large enough to account for any buffering that is expected (network related for HTTP/RTP/... streams, and worst-case audio device latency).

Flags: Read / Write

Default value: 300000000

The `“playlist”` property

  “playlist”                 GVariant *

A GVariant tuple of the current track index and an array of playlist entries. Each playlist entry, in turn, is a tuple of a URI and its duration. Unknown durations can be set to 0, which might cause a small (network-dependent) delay in swiching tracks.

See gst_sync_server_playlist_new() and related functions for easy manipulation of these playlists.

Flags: Read / Write

Allowed values: GVariant<(ta(st))>

Default value: NULL

The `“stream-start-delay”` property

  “stream-start-delay”       guint64

The amount of time to wait between streams before starting. This allows for devices which take different amounts of time to load the data (either due to network delays or differing storage speeds) to start smoothly at the same time when switching streams.

Flags: Read / Write

Default value: 500000000

Signal Details

The `“end-of-playlist”` signal

void
user_function (GstSyncServer *arg0,
               gpointer       user_data)

Emitted when the currently all the songs in the playlist have finished playing.

Parameters

user_data

user data set when the signal handler was connected.

Flags: Run First

The `“end-of-stream”` signal

void
user_function (GstSyncServer *arg0,
               gpointer       user_data)

Emitted when the currently playing URI reaches the end of the stream. This is called for each stream in the current playlist.

Parameters

user_data

user data set when the signal handler was connected.

Flags: Run First

GstSyncServer

Functions

Properties

Signals

Types and Values

Object Hierarchy

Description

Functions

gst_sync_server_new ()

Parameters

Returns

gst_sync_server_start ()

Parameters

Returns

gst_sync_server_stop ()

Parameters

gst_sync_server_set_stopped ()

Parameters

gst_sync_server_set_paused ()

Parameters

gst_sync_server_playlist_new ()

Parameters

Returns

gst_sync_server_playlist_set_tracks ()

Parameters

Returns

gst_sync_server_playlist_set_current_track ()

Parameters

Returns

gst_sync_server_playlist_get_tracks ()

Parameters

gst_sync_server_playlist_free_tracks ()

Parameters

gst_sync_server_playlist_get_current_track ()

Parameters

Returns

Types and Values

GstSyncServer

Property Details

The “control-address” property

The “control-port” property

The “control-server” property

The “latency” property

The “playlist” property

The “stream-start-delay” property

Signal Details

The “end-of-playlist” signal

Parameters

The “end-of-stream” signal

Parameters

The `“control-address”` property

The `“control-port”` property

The `“control-server”` property

The `“latency”` property

The `“playlist”` property

The `“stream-start-delay”` property

The `“end-of-playlist”` signal

The `“end-of-stream”` signal