TypeFindFactory

class TypeFindFactory(**properties: Any)

Superclasses: PluginFeature, Object, InitiallyUnowned, Object

These functions allow querying information about registered typefind functions. How to create and register these functions is described in the section <link linkend=”gstreamer-Writing-typefind-functions”> “Writing typefind functions”</link>.

The following example shows how to write a very simple typefinder that identifies the given data. You can get quite a bit more complicated than that though.

typedef struct {
  guint8 *data;
  guint size;
  guint probability;
  GstCaps *data;
} MyTypeFind;
static void
my_peek (gpointer data, gint64 offset, guint size)
{
  MyTypeFind *find = (MyTypeFind *) data;
  if (offset >= 0 && offset + size <= find->size) {
    return find->data + offset;
  }
  return NULL;
}
static void
my_suggest (gpointer data, guint probability, GstCaps *caps)
{
  MyTypeFind *find = (MyTypeFind *) data;
  if (probability > find->probability) {
    find->probability = probability;
    gst_caps_replace (&find->caps, caps);
  }
}
static GstCaps *
find_type (guint8 *data, guint size)
{
  GList *walk, *type_list;
  MyTypeFind find = {data, size, 0, NULL};
  GstTypeFind gst_find = {my_peek, my_suggest, &find, };
  walk = type_list = gst_type_find_factory_get_list ();
  while (walk) {
    GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (walk->data);
    walk = g_list_next (walk)
    gst_type_find_factory_call_function (factory, &gst_find);
  }
  g_list_free (type_list);
  return find.caps;
};

Methods

class TypeFindFactory

call_function(find: TypeFind) → None

Calls the TypeFindFunction associated with this factory.

Parameters:

find – a properly setup TypeFind entry. The get_data and suggest_type members must be set.

get_caps() → Caps | None

Gets the Caps associated with a typefind factory.

get_extensions() → list[str] | None

Gets the extensions associated with a TypeFindFactory. The returned array should not be changed. If you need to change stuff in it, you should copy it using strdupv(). This function may return None to indicate a 0-length list.

get_list() → list[TypeFindFactory]

Gets the list of all registered typefind factories. You must free the list using list_free().

The returned factories are sorted by highest rank first, and then by factory name.

Free-function: gst_plugin_feature_list_free

has_function() → bool

Check whether the factory has a typefind function. Typefind factories without typefind functions are a last-effort fallback mechanism to e.g. assume a certain media type based on the file extension.