GstCaps Capabilities of pads GstCaps is used to attach capabilities to a pad. Capabilities are made of a mime-type and a set of properties. GstCaps can be named and chained into a list, which is then a GstCaps on its own. GstCaps are created with gst_caps_new(), which takes a name, a mime type and a pointer to a #GstProps. A convenience macro with a cleaner syntax is available to create a caps with GST_CAPS_NEW(). The following example shows how to create a GstCaps. GstCaps *caps; caps = gst_caps_new ( "my_caps", /* capability name */ "audio/raw", /* mime type */ gst_props_new ( /* properties */ "format", GST_PROPS_STRING ("float"), "layout", GST_PROPS_INT (5), NULL)); The following code example is equivalent to the above example: GstCaps *caps; caps = GST_CAPS_NEW ( "my_caps", /* capability name */ "audio/raw", /* mime type */ "format", GST_PROPS_STRING ("float"), "channels", GST_PROPS_INT (5) ); GstCaps are refcounted with gst_caps_ref() and gst_caps_unref(). GstCaps can be chained with the gst_caps_append(), gst_caps_prepend() and gst_caps_chain() functions. Use gst_caps_get_by_name() to get a named caps structure from a chained list. To get the properties of a caps structure the functions gst_caps_get_boolean(), gst_caps_get_fourcc_int(), gst_caps_get_int(), gst_caps_get_string(), gst_caps_get_float(), which all take a property name as an argument. The properties of the caps structure can be modified with gst_caps_set, which takes a list of key value pairs in the #GstProps syntax as shown by this example: GstCaps *caps; .... gst_caps_set (caps, "format", GST_PROPS_STRING ("int"), NULL); gst_caps_set (caps, "channels", GST_PROPS_INT (20), NULL); before modifying a GstCaps, it is a good idea to make a copy if it first with gst_caps_copy_on_write(). This will copy the GstCaps if the refcount is >1. If you need a unique instance of a GstCaps you can use the convenient GST_CAPS_FACTORY() macro as shown below. GST_CAPS_FACTORY (my_caps, GST_CAPS_NEW ( "caps1", "audio/raw", "format", GST_PROPS_STRING ("float"), "channels", GST_PROPS_INT (5) ), GST_CAPS_NEW ( "caps2", "audio/raw", "format", GST_PROPS_STRING ("int"), "channels", GST_PROPS_INT (5) ) ) void some_function (void) { GstCaps *caps = GST_CAPS_GET (my_caps); ... } #GstProps, #GstPad The GType of the caps boxed type, for use in GValues. A convenience macro to create a new GstCaps structure. @name: the name of the caps structure @type: the mime type of the caps structure @a...: the properties of this caps stucture. A convenience macro to create a GstCaps factory. @factoryname: the name of the factory @a...: the caps to create with this factory, usualy specified with GST_CAPS_NEW() A convenience macro to get a GstCaps from the given capsfactory. @fact: the factory to use. Check if the GstCaps is chained. @caps: the caps to query Check if the GstCaps has fixed properties, ie. it has no ranges or lists. @caps: the caps to query @name: the name of the capability, for the application @id: the typeid of the capability @refcount: a refcounter for this caps structure @fixed: a boolean indicating that this caps structure is fixed @properties: the properties of the capability @next: a pointer to the next caps. @name: @mime: @props: @Returns: @name: @id: @props: @Returns: @caps: @caps: @Returns: @caps: @Returns: @caps: @Returns: @caps: @Returns: @caps: @Returns: @caps: @Varargs: @Returns: @caps: @capstoadd: @Returns: @caps: @capstoadd: @Returns: @caps: @name: @caps: @Returns: @caps: @type_id: @caps: @Returns: @caps: @mime: @caps: @Returns: @caps: @props: @Returns: @caps: @Returns: @fromcaps: @tocaps: @Returns: Check if the GstCaps has a property with the given name @caps: the caps to query @name: the name of the property Check if the GstCaps has a fixed property with the given name @caps: the caps to query @name: the name of the property Check if the GstCaps has a property with the given type @caps: the caps to query @name: the name of the property @type: @caps: @Returns: Set a property of a caps structure. @caps: the caps structure to modify @name: the name of the property to change @args...: the new value of the property Get key/value pairs from the given GstCaps. @caps: the caps to get the values from @name: the name of the first key @args...: a pointer to the variable that can hold the result followed by more key/value pairs. @caps1: @caps2: @Returns: Get the value of the named property as a boolean. @caps: the caps to query @name: the name of the property to get @res: a pointer to a gboolean to store the result @caps: @name: @Returns: Get the value of the named property as a fourcc. @caps: the caps to query @name: the name of the property to get @res: a pointer to a guint32 to store the fourcc value Get the value of the named property as an int. @caps: the caps to query @name: the name of the property to get @res: a pointer to a gint to store the value Get the value of the named property as a string. @caps: the caps to query @name: the name of the property to get @res: a pointer to a gchar* to store the string Get the value of the named property as a float. @caps: the caps to query @name: the name of the property to get @res: a pointer to a gfloat to store the result @caps: @parent: @Returns: @parent: @Returns: @caps: @label: