static void gstCBfilterPadAdded(GstElement *filter, GstPad *pad, gpointer user_data); /* for id3demux */
static void gstCBnewPad(GstElement *decodebin, GstPad *pad, gboolean last, gpointer data); /* for decodebin */
static void gstCBunknownType(GstElement *decodebin, GstPad *pad, GstCaps *l, gpointer data);
static void gstCBfilterPadAdded(GstElement *filter, GstPad *pad, gpointer user_data); /* for id3demux */
static void gstCBnewPad(GstElement *decodebin, GstPad *pad, gboolean last, gpointer data); /* for decodebin */
static void gstCBunknownType(GstElement *decodebin, GstPad *pad, GstCaps *l, gpointer data);