gstreamer : encountered a general stream error - gstreamer

Question

Now I'm trying to play mp4 files.
After trying to play mp4 file to demux, a stream error occurs.
My code is below, please let me know if there are any problems.
Any advises? Thank you
error -> encountered a general stream error
int main(int argc, char* argv[]){
GMainLoop *loop;
GstElement *pipeline, *vsource, *demux, *vqueue, *ssource, *muxer, *filesink;
GstElement *vplay, *conv;
//GstBin *recording;
GstBus *bus;
GstPad *srcpad, *sinkpad;
guint bus_watch_id;
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);
pipeline = gst_pipeline_new("Live Recording");
vsource = gst_element_factory_make("filesrc","v-file-source");
demux = gst_element_factory_make("qtdemux","v-file-demux");
vqueue = gst_element_factory_make("queue2","v-file-queue");
vplay = gst_element_factory_make("autovideosink","play");
conv = gst_element_factory_make("videoconvert","converter");
if(!pipeline)
g_print("no pipe\n");
if(!vsource)
g_print("no video source\n");
if(!demux)
g_print("no video demux\n");
if(!vqueue)
g_print("no video queue\n");
if(!vplay)
g_print("no video play\n");
if(!conv)
g_print("no conv");
g_object_set (G_OBJECT (vsource), "location", "./sample.mp4", NULL);
bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));
bus_watch_id = gst_bus_add_watch(bus, bus_call, loop);
gst_object_unref(bus);
gst_bin_add_many(GST_BIN(pipeline),vsource,demux,vqueue, conv, vplay,NULL);
if(!gst_element_link(vsource, demux)){
g_print("no link");
}
if(!gst_element_link_many(vqueue, conv, vplay,NULL)){
g_print("no link many");
}
g_print("now play\n");
g_signal_connect (demux, "pad-added", G_CALLBACK (on_pad_added), vqueue);
gst_element_set_state(pipeline, GST_STATE_PLAYING);
g_main_loop_run(loop);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref(GST_OBJECT(pipeline));
g_source_remove(bus_watch_id);
g_main_loop_unref(loop);
return 0;
}