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| void | gst_init () |
| gboolean | gst_init_check () |
| GOptionGroup * | gst_init_get_option_group () |
| gboolean | gst_is_initialized () |
| void | gst_deinit () |
| void | gst_version () |
| gchar * | gst_version_string () |
| gboolean | gst_segtrap_is_enabled () |
| void | gst_segtrap_set_enabled () |
| gboolean | gst_registry_fork_is_enabled () |
| void | gst_registry_fork_set_enabled () |
| gboolean | gst_update_registry () |
GStreamer is a framework for constructing graphs of various filters (termed elements here) that will handle streaming media. Any discrete (packetizable) media type is supported, with provisions for automatically determining source type. Formatting/framing information is provided with a powerful negotiation framework. Plugins are heavily used to provide for all elements, allowing one to construct plugins outside of the GST library, even released binary-only if license require (please don't). GStreamer covers a wide range of use cases including: playback, recording, editing, serving streams, voice over ip and video calls.
The GStreamer library should be initialized with
gst_init() before it can be used. You should pass pointers to the main argc
and argv variables so that GStreamer can process its own command line
options, as shown in the following example.
Example 1. Initializing the gstreamer library
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int main (int argc, char *argv[]) { // initialize the GStreamer library gst_init (&argc, &argv); ... } |
It's allowed to pass two NULL pointers to gst_init() in case you don't want
to pass the command line args to GStreamer.
You can also use GOption to initialize your own parameters as shown in the next code fragment:
Example 2. Initializing own parameters when initializing gstreamer
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static gboolean stats = FALSE; ... int main (int argc, char *argv[]) { GOptionEntry options[] = { {"tags", 't', 0, G_OPTION_ARG_NONE, &tags, N_("Output tags (also known as metadata)"), NULL}, {NULL} }; ctx = g_option_context_new ("[ADDITIONAL ARGUMENTS]"); g_option_context_add_main_entries (ctx, options, GETTEXT_PACKAGE); g_option_context_add_group (ctx, gst_init_get_option_group ()); if (!g_option_context_parse (ctx, &argc, &argv, &err)) { g_print ("Error initializing: %s\n", GST_STR_NULL (err->message)); exit (1); } g_option_context_free (ctx); ... } |
Use gst_version() to query the library version at runtime or use the
GST_VERSION_* macros to find the version at compile time. Optionally
gst_version_string() returns a printable string.
The gst_deinit() call is used to clean up all internal resources used
by GStreamer. It is mostly used in unit tests
to check for leaks.
void gst_init (int *argc,char **argv[]);
Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.
Unless the plugin registry is disabled at compile time, the registry will be
loaded. By default this will also check if the registry cache needs to be
updated and rescan all plugins if needed. See gst_update_registry() for
details and section
for how to disable automatic registry updates.
This function will terminate your program if it was unable to initialize
GStreamer for some reason. If you want your program to fall back,
use gst_init_check() instead.
WARNING: This function does not work in the same way as corresponding
functions in other glib-style libraries, such as gtk_init(). In
particular, unknown command line options cause this function to
abort program execution.
gboolean gst_init_check (int *argc,char **argv[],GError **err);
Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.
This function will return FALSE if GStreamer could not be initialized
for some reason. If you want your program to fail fatally,
use gst_init() instead.
argc |
pointer to application's argc. |
[inout][allow-none] |
argv |
pointer to application's argv. |
[inout][array length=argc][allow-none] |
err |
pointer to a GError to which a message will be posted on error |
GOptionGroup *
gst_init_get_option_group (void);
Returns a GOptionGroup with GStreamer's argument specifications. The group is set up to use standard GOption callbacks, so when using this group in combination with GOption parsing methods, all argument parsing and initialization is automated.
This function is useful if you want to integrate GStreamer with other
libraries that use GOption (see g_option_context_add_group() ).
If you use this function, you should make sure you initialise the GLib threading system as one of the very first things in your program (see the example at the beginning of this section).
[skip]
gboolean
gst_is_initialized (void);
Use this function to check if GStreamer has been initialized with gst_init()
or gst_init_check().
void
gst_deinit (void);
Clean up any resources created by GStreamer in gst_init().
It is normally not needed to call this function in a normal application as the resources will automatically be freed when the program terminates. This function is therefore mostly used by testsuites and other memory profiling tools.
After this call GStreamer (including this method) should not be used anymore.
void gst_version (guint *major,guint *minor,guint *micro,guint *nano);
Gets the version number of the GStreamer library.
gchar *
gst_version_string (void);
This function returns a string that is useful for describing this version of GStreamer to the outside world: user agent strings, logging, ...
gboolean
gst_segtrap_is_enabled (void);
Some functions in the GStreamer core might install a custom SIGSEGV handler to better catch and report errors to the application. Currently this feature is enabled by default when loading plugins.
Applications might want to disable this behaviour with the
gst_segtrap_set_enabled() function. This is typically done if the application
wants to install its own handler without GStreamer interfering.
void
gst_segtrap_set_enabled (gboolean enabled);
Applications might want to disable/enable the SIGSEGV handling of
the GStreamer core. See gst_segtrap_is_enabled() for more information.
gboolean
gst_registry_fork_is_enabled (void);
By default GStreamer will perform scanning and rebuilding of the registry file using a helper child process.
Applications might want to disable this behaviour with the
gst_registry_fork_set_enabled() function, in which case new plugins
are scanned (and loaded) into the application process.
void
gst_registry_fork_set_enabled (gboolean enabled);
Applications might want to disable/enable spawning of a child helper process
when rebuilding the registry. See gst_registry_fork_is_enabled() for more
information.
gboolean
gst_update_registry (void);
Forces GStreamer to re-scan its plugin paths and update the default plugin registry.
Applications will almost never need to call this function, it is only
useful if the application knows new plugins have been installed (or old
ones removed) since the start of the application (or, to be precise, the
first call to gst_init()) and the application wants to make use of any
newly-installed plugins without restarting the application.
Applications should assume that the registry update is neither atomic nor thread-safe and should therefore not have any dynamic pipelines running (including the playbin and decodebin elements) and should also not create any elements or access the GStreamer registry while the update is in progress.
Note that this function may block for a significant amount of time.