TypeFindFactory

These functions allow querying information about registered typefind functions.

How to create and register these functions is described in the section "Writing typefind functions".

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;
  };