GStreamer connection to VLC using GstRTSP library - gstreamer

Question

I am trying to write a C application to connect with VLC RTSP (via RTP) stream and save frames as images.
I use the GStreamer RTSP library: https://gstreamer.freedesktop.org/documentation/gst-plugins-base-rtsp-1.0/index.html?gi-language=c
I have written some simple code presented below, but the app wait for the message from the VLC. I am not sure if it is a good way to connect but I am in stuck now. Maybe I should send something first to VLC but I do not know what and how to do this. Could anyone help or point some resources/examples how to use GStreamer RTSP?
#include <gstreamer-1.0/gst/rtsp/rtsp.h>
#include <stdio.h>
int main()
{
GstRTSPUrl *gstUrl = NULL;
const char* url = "rtsp://10.30.1.163:8554/test.sdp";
if(gst_rtsp_url_parse(url, &gstUrl) == GST_RTSP_OK) {
printf("URL PARSE");
GstRTSPConnection *gstRTSPConnection = NULL;
if(gst_rtsp_connection_create(gstUrl, &gstRTSPConnection) == GST_RTSP_OK) {
printf("Connection created\n");
GstRTSPMessage *message = NULL;
gst_rtsp_message_new(&message);
GstRTSPResult result = gst_rtsp_connection_connect_with_response(gstRTSPConnection, NULL, message);
if(result == GST_RTSP_ETIMEOUT){
printf("Timeout\n");
} else if(result == GST_RTSP_OK) {
printf("Connected\n");
printf("%s\n", gst_rtsp_connection_get_ip(gstRTSPConnection));
printf("Is tunelled: %d\n", gst_rtsp_connection_is_tunneled(gstRTSPConnection));
gst_rtsp_connection_receive(gstRTSPConnection, message, NULL);
}
}
}
return 0;
}

Answer 1

Ok. I will handle this. The issue was I need to first send some message to the server according to RTSP protocol. The solution below (with some dump messages):
#include <gstreamer-1.0/gst/rtsp/rtsp.h>
#include <stdio.h>
int main()
{
GstRTSPUrl *gstUrl = NULL;
const char* url = "rtsp://10.30.1.163:8554";
if(gst_rtsp_url_parse(url, &gstUrl) == GST_RTSP_OK) {
printf("URL PARSE");
GstRTSPConnection *gstRTSPConnection = NULL;
if(gst_rtsp_connection_create(gstUrl, &gstRTSPConnection) == GST_RTSP_OK) {
printf("Connection created\n");
GstRTSPMessage *message = NULL;
gst_rtsp_message_new(&message);
GstRTSPResult result = gst_rtsp_connection_connect_with_response(gstRTSPConnection, NULL, message);
if(result == GST_RTSP_ETIMEOUT){
printf("Timeout\n");
} else if(result == GST_RTSP_OK) {
printf("Connected\n");
printf("%s\n", gst_rtsp_connection_get_ip(gstRTSPConnection));
printf("Is tunelled: %d\n", gst_rtsp_connection_is_tunneled(gstRTSPConnection));
gst_rtsp_message_new(&message);
gst_rtsp_message_init_request(message, GST_RTSP_DESCRIBE, "rtsp://10.30.1.163:8554/test.sdp");
gst_rtsp_message_add_header(message, GST_RTSP_HDR_CSEQ, "1");
printf("Message Type %d", gst_rtsp_message_get_type(message));
gst_rtsp_message_dump(message);
if(gst_rtsp_connection_send(gstRTSPConnection, message, NULL) == GST_RTSP_OK){
printf("Message sent");
}else {
printf("Message not sent");
}
gst_rtsp_connection_receive(gstRTSPConnection, message, NULL);
gst_rtsp_message_dump(message);
}
}
}
return 0;
}