a timeout in nanoseconds, or GST_CLOCK_TIME_NONE to wait forever
message types to take into account, GST_MESSAGE_ANY for any type
a GstMessage matching the filter in types, or NULL if no matching message was found on the bus until the timeout expired. The message is taken from the bus and needs to be unreffed with gst_message_unref() after usage. MT safe. [transfer full]
Get a message from the bus whose type matches the message type mask types, waiting up to the specified timeout (and discarding any messages that do not match the mask provided). If timeout is 0, this function behaves like gst_bus_pop_filtered(). If timeout is GST_CLOCK_TIME_NONE, this function will block forever until a matching message was posted on the bus.