How to use splitmuxsink in a dynamic pipeline

Question

What is the correct way of using splitmuxsink in a dynamic pipeline?

Previously I have used filesink to record (no problem what so ever) but there is requirement to save the file in segments so I have tried to use splitmuxsink in dynamic pipeline(there is async time in recording). In doing so I have faced two problems

1. when I tried to stop the recording, I use a idle pad to block the recording queue and launch a callback function to do steps to delink the recording branch (send eos, set elements in recording bin to NULL, then dequeue the bin). I have set a downstream data probe to notify me that the eos has reached the splitmuxsink sink before I tried to do step 2..(set elemets to null)

   However, the end result is that i still have an empty last file (o bytes). It seem that the pipe is not yet closed or having some problem. I did a workaround to split the video immediately when the record stop (though I lost a few frames)

   How should one stop in a dynamic branch?

2. When I tried to create the recording bin when i start the recording(utilizing the pad-added signal when a pad is created to connect the recording bin). Previously I have created the recording bin in normal sequence (not creating them during the glib loop that I have created). The previous step work ok but the present step has the splitmuxsink's filesink in a locked state

   How should I workaround this? What causes the lock state?

Here is my code

/// create record bin
static void
pad-added(GstElement * self,
               GstPad * new_pad,
               gpointer user_data)
{
    char* pad_name = gst_pad_get_name(new_pad);
    if(g_str_equal(pad_name,"src"))
    {

        //RECORD records;
        records.recording    = gst_bin_new("recording");
        records.queue       = gst_element_factory_make("queue","queue");
        records.enc         = gst_element_factory_make("vpuenc_h264","enc");
        records.parser       = gst_element_factory_make("h264parse","parser");
        records.sink        = gst_element_factory_make("splitmuxsink","sink");


        // Add it to the main pipeline
        gst_bin_add_many(GST_BIN(records.recording),
                                 records.queue,
                                 records.enc,
                                 records.parser,
                                 records.sink,NULL);

        // link up the recording elements queue
        gst_element_link_many(records.queue,
                                  records.enc,
                                  records.parser,
                                  records.sink,NULL)
    
        
        g_object_set(G_OBJECT(records.fsink),
                     //"location","video_%d.mp4",
                     "max-size-time", (guint64) 10L * GST_SECOND,
                     "async-handling", TRUE,
                     "async-finalize", TRUE,
                     NULL);

        records.queue_sink_pad = gst_element_get_static_pad (records.queue, "sink");
        records.ghost_pad = gst_ghost_pad_new ("sink", records.queue_sink_pad);
        gst_pad_set_active(records.ghost_pad, TRUE);

        gst_element_add_pad(GST_ELEMENT(records.recording),records.ghost_pad);

        g_signal_connect (records.sink, "format-location",
                         (GCallback)format_location_callback,
                         &records);
        
    }
}

gboolean cmd_loop()
{
   // other cmd not shown here

   if(RECORD)
   {
      //create tee sink pad
      // this step will trigger the pad-added function
      tee_sink_pad = gst_element_get_request_pad (tee,"src");

      // ....other function
   }
} 

int main()
{
   // add the pad-added signal response
   g_signal_connect(tee, "pad-added", G_CALLBACK(pad-added), NULL);

  // use to construct the loop (cycle every 1s)
   GSource* source = g_timeout_source_new(1000);

   // set function to watch for command 
   g_source_set_callback(source,
                          (GSourceFunc)cmd_loop,
                          NULL,
                          NULL);
}