Hi, I'm writing a custom plugin ( the plugin is the combined of videorate and capsfilter) to adjust fps at run-time by changing "caps" property of capsfilter element. But to make the new fps get effect, I need to change pipeline state to PAUSED, change "caps" property and then change pipeline state to PLAYING. Here's the result: - using gst_element_set_state(), gst-launch told that I should not change state inside element thread, post a GstMessage. - post a GstMessage, then I got this error: ** (gst-launch-0.10:7370): WARNING **: Old state = 4, current state = 0, next state = 0, new state = 2 ** (gst-launch-0.10:7370): WARNING **: Old state = 4, current state = 0, next state = 0, new state = 4 (gst-launch-0.10:7370): GLib-GObject-WARNING **: invalid unclassed pointer in cast to `GstMessage' (gst-launch-0.10:7370): GLib-GObject-WARNING **: invalid unclassed pointer in cast to `GstMessage' (gst-launch-0.10:7370): GStreamer-CRITICAL **: gst_value_set_mini_object: assertion `mini_object == NULL || GST_IS_MINI_OBJECT (mini_object)' failed Caught SIGSEGV accessing address 0x18 Killed So is there any one got an idea for me? Thanks -- Cheers ! trungnt