ros_rtsp/src/image2rtsp.cpp

#include <string>
#include <stdio.h>
#include <nodelet/nodelet.h>
#include <pluginlib/class_list_macros.h>
#include <gst/gst.h>
#include <gst/app/gstappsrc.h>
#include <gst/rtsp-server/rtsp-server.h>
#include <ros/ros.h>
#include "sensor_msgs/Image.h"
#include <sensor_msgs/image_encodings.h>
#include <image2rtsp.h>


using namespace std;
using namespace image2rtsp;


void Image2RTSPNodelet::onInit() {
	string pipeline, mountpoint, bitrate, caps;
	string pipeline_tail =  " key-int-max=30 ! video/x-h264, profile=baseline ! rtph264pay name=pay0 pt=96 )"; // Gets completed based on rosparams below

	NODELET_DEBUG("Initializing image2rtsp nodelet...");

	if (getenv((char*)"GST_DEBUG") == NULL) {
		// set GST_DEBUG to warning if unset
		putenv((char*)"GST_DEBUG=*:2");
	}

	appsrc = NULL;
	ros::NodeHandle& nh = getPrivateNodeHandle();

	video_mainloop_start();
	rtsp_server = rtsp_server_create();

	// Get the parameters from the rosparam server
	XmlRpc::XmlRpcValue streams;
	nh.getParam("streams", streams);
	ROS_ASSERT(streams.getType() == XmlRpc::XmlRpcValue::TypeStruct);

	ROS_INFO("Number of RTSP streams: %d", streams.size());

	// Go through and parse each stream
	for(XmlRpc::XmlRpcValue::ValueStruct::const_iterator it = streams.begin(); it != streams.end(); ++it) 
	{
		XmlRpc::XmlRpcValue stream = streams[it->first];
    	ROS_INFO_STREAM("Found stream: " << (std::string)(it->first) << " ==> " << stream);
		
		// Convert to string for ease of use
		mountpoint = static_cast<std::string>(stream["mountpoint"]);
		bitrate = std::to_string(static_cast<int>(stream["bitrate"]));
		caps = static_cast<std::string>(stream["caps"]);

		// uvc camera?
		if (stream["type"]=="cam")
		{
			pipeline = "( v4l2src device=" + static_cast<std::string>(stream["source"]) + " ! videoconvert ! videoscale ! " + caps + " ! x264enc tune=zerolatency bitrate=" + bitrate + pipeline_tail;

			rtsp_server_add_url(mountpoint.c_str(), pipeline.c_str(), NULL);
		}
		// ROS Image topic?
		else if (stream["type"]=="topic")
		{
			/* Keep record of number of clients connected to each topic.
			* so we know to stop subscribing when no-one is connected. */
			num_of_clients[mountpoint] = 0;

			// Setup the full pipeline
			pipeline = "( appsrc name=imagesrc do-timestamp=true min-latency=0 max-latency=0 max-bytes=1000 is-live=true ! videoconvert ! videoscale ! " + caps + " ! x264enc tune=zerolatency bitrate=" + bitrate + pipeline_tail;

			// Add the pipeline to the rtsp server
			rtsp_server_add_url(mountpoint.c_str(), pipeline.c_str(), (GstElement **)&appsrc);
		}
		else
		{
			ROS_ERROR("Undefined stream type. Check your stream_setup.yaml file.");
		}
	}
}

/* Modified from https://github.com/ProjectArtemis/gst_video_server/blob/master/src/server_nodelet.cpp */
GstCaps* Image2RTSPNodelet::gst_caps_new_from_image(const sensor_msgs::Image::ConstPtr &msg)
{
	// http://gstreamer.freedesktop.org/data/doc/gstreamer/head/pwg/html/section-types-definitions.html
	static const ros::M_string known_formats = {{
		{sensor_msgs::image_encodings::RGB8, "RGB"},
		{sensor_msgs::image_encodings::RGB16, "RGB16"},
		{sensor_msgs::image_encodings::RGBA8, "RGBA"},
		{sensor_msgs::image_encodings::RGBA16, "RGBA16"},
		{sensor_msgs::image_encodings::BGR8, "BGR"},
		{sensor_msgs::image_encodings::BGR16, "BGR16"},
		{sensor_msgs::image_encodings::BGRA8, "BGRA"},
		{sensor_msgs::image_encodings::BGRA16, "BGRA16"},
		{sensor_msgs::image_encodings::MONO8, "GRAY8"},
		{sensor_msgs::image_encodings::MONO16, "GRAY16_LE"},
	}};

	if (msg->is_bigendian) {
		ROS_ERROR("GST: big endian image format is not supported");
		return nullptr;
	}

	auto format = known_formats.find(msg->encoding);
	if (format == known_formats.end()) {
		ROS_ERROR("GST: image format '%s' unknown", msg->encoding.c_str());
		return nullptr;
	}

	return gst_caps_new_simple("video/x-raw",
			"format", G_TYPE_STRING, format->second.c_str(),
			"width", G_TYPE_INT, msg->width,
			"height", G_TYPE_INT, msg->height,
			"framerate", GST_TYPE_FRACTION, 10, 1,	// 0/1 = dynamic
			nullptr);
}


void Image2RTSPNodelet::imageCallback(const sensor_msgs::Image::ConstPtr& msg) {
	GstBuffer *buf;

	GstCaps *caps;
	char *gst_type, *gst_format=(char *)"";

	// g_print("Image encoding: %s\n", msg->encoding.c_str());

	if (appsrc != NULL) {
		// Set caps from message
		caps = gst_caps_new_from_image(msg);
		gst_app_src_set_caps(appsrc, caps);

		buf = gst_buffer_new_allocate(nullptr, msg->data.size(), nullptr);
		gst_buffer_fill(buf, 0, msg->data.data(), msg->data.size());
		GST_BUFFER_FLAG_SET(buf, GST_BUFFER_FLAG_LIVE);

		gst_app_src_push_buffer(appsrc, buf);
	}
}


void Image2RTSPNodelet::url_connected(string url) {
	std::string mountpoint, source;

	NODELET_INFO("Client connected: %s", url.c_str());
	ros::NodeHandle& nh = getPrivateNodeHandle();

	// Get the parameters from the rosparam server
	XmlRpc::XmlRpcValue streams;
	nh.getParam("streams", streams);
	ROS_ASSERT(streams.getType() == XmlRpc::XmlRpcValue::TypeStruct);

	// Go through and parse each stream
	for(XmlRpc::XmlRpcValue::ValueStruct::const_iterator it = streams.begin(); it != streams.end(); ++it) 
	{
		XmlRpc::XmlRpcValue stream = streams[it->first];
		mountpoint = static_cast<std::string>(stream["mountpoint"]);
		source = static_cast<std::string>(stream["source"]);

		// Check which stream the client has connected to
		if (url==mountpoint) {

			if (num_of_clients[url]==0) {
				// Subscribe to the ROS topic
				sub = nh.subscribe(source, 10, &Image2RTSPNodelet::imageCallback, this);
			}
			num_of_clients[url]++;
		}
	}
}

void Image2RTSPNodelet::url_disconnected(string url) {
	std::string mountpoint;

	NODELET_INFO("Client disconnected: %s", url.c_str());
	ros::NodeHandle& nh = getPrivateNodeHandle();

	// Get the parameters from the rosparam server
	XmlRpc::XmlRpcValue streams;
	nh.getParam("streams", streams);
	ROS_ASSERT(streams.getType() == XmlRpc::XmlRpcValue::TypeStruct);

	// Go through and parse each stream
	for(XmlRpc::XmlRpcValue::ValueStruct::const_iterator it = streams.begin(); it != streams.end(); ++it) 
	{
		XmlRpc::XmlRpcValue stream = streams[it->first];
		mountpoint = static_cast<std::string>(stream["mountpoint"]);

		// Check which stream the client has disconnected from
		if (url==mountpoint) {
			if (num_of_clients[url] > 0) num_of_clients[url]--;
			if (num_of_clients[url] == 0) {
				// No-one else is connected. Stop the subscription.
				sub.shutdown();
				appsrc = NULL;
			}
		}
	}
}

void Image2RTSPNodelet::print_info(char *s) {
	NODELET_INFO(s);
}

void Image2RTSPNodelet::print_error(char *s) {
	NODELET_ERROR(s);
}

PLUGINLIB_EXPORT_CLASS(image2rtsp::Image2RTSPNodelet, nodelet::Nodelet)