Welcome!

Eclipse Authors: Elizabeth White, Liz McMillan, XebiaLabs Blog, Ken Fogel, Sematext Blog

Blog Feed Post

Extreme HTML5 Video Interactivity: Sending WebSocket Messages with Popcorn.js

One of our most popular demos at Kaazing is using a Web browser on a smartphone to control a physical toy truck from continents away. The truck has a Raspberry Pi attached to it, connecting to a WebSocket server, and listening to control command messages: drive forward or backward, turn left or right, or turn headlight on and off. You can learn more about the project in our Remote Controlling a Car over the Web. Ingredients: Smartphone, WebSocket, and Raspberry Pi blog post.

The most interesting way to demonstrate the truck is by having a remote person control the truck, and join in over a video conference. Here’s the recording of us doing just this. Fast forward to 4:08 for the truck demo.

Now, there are certain circumstances, when running Skype, or other live video chat apps is not an option. You may be off the grid, or simply not have anybody handy controlling your truck remotely.

To address this challenge, we wanted to create a self-contained environment where the same dialog and experience can be presented, but without all the above mentioned dependencies. To achieve this, we decided to record a video of someone operating the remote control that the presenter could use as the “Skyped-in” portion of the presentation. There are a number of ways we could hack this, for example by pretending to control the car by emulating the controls in the room. How cool would it be to instead have the recorded video actually trigger the remote controls using WebSocket messages? Instead of a real person controlling the car in real time, we could have the video control the car in real time.

First, we recorded the video. In the video, David Witherspoon operates the remote control. (Aside: David is a software engineer at Kaazing who, along with colleague Prashant Khanal, was instrumental in dreaming up and building the truck). David followed the script of the dialog very precisely. Knowing the script was not sufficient, we had to do it with exact timing, as it was specified to be run during the actual demo.

After processing the video, I embedded it in a web page, and overlaid the video with a live video feed of the presenter’s laptop camera. This is an important step to make the experience more realistic; after all, every video conference does this.

Here’s the HTML code:

	<head>
		<script src="http://popcornjs.org/code/dist/popcorn-complete.min.js"></script>
		<script src="http://demo.kaazing.com/lib/client/javascript/StompJms.js"></script>
		<script>document.addEventListener( "DOMContentLoaded", function() {doConnect();}, false );</script>
		<link rel="stylesheet" href="css/truck.css"</style>
	</head>
	<body>
		<video id="selfVideo" autoplay width="256"></video>
		<video id="truckVideo" width="1024">
			<!-- <source src="videos/PeterTruck.mp4" type="video/mp4"> -->
			<source src="http://localhost/videos/DavidTruck.mp4" type="video/mp4">
		</video>
	</body>
	<script src="js/truck.js"></script>	

And here is the JavaScript code:

var errorCallback = function(e) {
console.log('Reeeejected!', e);
};

// Not showing vendor prefixes.
navigator.getUserMedia  = navigator.getUserMedia ||
              navigator.webkitGetUserMedia ||
              navigator.mozGetUserMedia ||
              navigator.msGetUserMedia;

var video = document.getElementById ("selfVideo");

if (navigator.getUserMedia) {
  navigator.getUserMedia({audio: false, video: true}, function(stream) {
    video.src = window.URL.createObjectURL(stream);
  }, errorCallback);
} else {
  video.src = 'somevideo.webm'; // fallback.
}

The simple CSS snippet ensures that the presenter’s “self” video overlays the remote person’s (recorded) video.

#selfVideo
	{position:fixed;
	top:30px;
	left:30px;}

Also, browsers are required to prompt for permission before Web apps can start using the built-in camera. First, you have to select Allow, for the “little video” in the top left corner to appear. Here’s what the permission request bar looks like in Chrome:

usecamera

And here’s the end result:

popcornvideo

Whenever my actor friend in the main video uses his remote control, we must trigger a corresponding WebSocket message. The messages are sent by the Web app hosting the video at the exact time when the control is touched in the video. I used popcorn.js, an open source media library, to get the timing right:

Popcorn.js is an HTML5 media framework written in JavaScript for filmmakers, web developers, and anyone who wants to create time-based interactive media on the web. Popcorn.js is part of Mozilla’s Popcorn project.

I created an array with the timing and the messages that needed to be sent. The timing is measured in seconds.

var davidTruckMsgs = [
[33,"frontlight;on"],
[35,"frontlight;off"],
[36,"frontlight;on"],
[38,"frontlight;off"],
[42,"steering;right : thrust;off"],
[43,"steering;left : thrust;off"],
[44,"steering;right: thrust;off"],
[45,"steering;left : thrust;off"],
[48,"steering;off : thrust;forward"],
[50,"steering;off : thrust;backward"],
[51,"steering;off : thrust;forward"],
[52,"steering;off : thrust;backward"],
[86,"steering;left : thrust;forward"]
];

Then, we have to schedule the WebSocket messages, as defined in the array specified above. Note: The above array is called davidTruckMsgs, and down below we iterate over the truckMsgs array. As you can see in the completed source code, I have multiple arrays for various videos/actors. Whichever is the one used at the moment is referenced as truckMsgs later on.

for (var truckMsg in truckMsgs) {
  var obj = truckMsgs[truckMsg];
  pop.cue( obj[0], makeCallback( obj ) );
}
pop.play();

The makeCallback function invokes the actual logic sending the WebSocket message. If you’re wondering why this is all needed in the first place, check out this question on Stack Overflow.

function makeCallback(obj) {
    return function() {
    	doSend(session.createTextMessage(obj[1]));
    };
}

For usability, I added pause/continue functionality whenever the main video is clicked. This gives the presenter more control, allowing him/her to preload the page with the main video paused on it.

vid = document.getElementById ("truckVideo");
vid.addEventListener ('click', function() {
     vid.paused ? vid.play() : vid.pause();
});

For the WebSocket communication we used the JMS edition of the Kaazing WebSocket Gateway, allowing us to leverage simple pub/sub messaging concepts. With the help of popcorn.js, from the HTML5 web app we publish WebSocket messages to a so called topic, and whoever is interested in (read: subscribed to) it will receive it.

This way the video is driving the truck, simply by having the WebSocket messages sent out properly timed to the pre-recorded video.

Here’s the end result. Isn’t it awesome?

You can see the entire source code on github.


Read the original blog entry...

More Stories By Kaazing Blog

Kaazing is helping define the future of the event-driven enterprise by accelerating the Web for the Internet of Things.

@ThingsExpo Stories
"We work in the area of Big Data analytics and Big Data analytics is a very crowded space - you have Hadoop, ETL, warehousing, visualization and there's a lot of effort trying to get these tools to talk to each other," explained Mukund Deshpande, head of the Analytics practice at Accelerite, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Cloud Expo, Inc. has announced today that Andi Mann returns to 'DevOps at Cloud Expo 2016' as Conference Chair The @DevOpsSummit at Cloud Expo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited t...
IoT offers a value of almost $4 trillion to the manufacturing industry through platforms that can improve margins, optimize operations & drive high performance work teams. By using IoT technologies as a foundation, manufacturing customers are integrating worker safety with manufacturing systems, driving deep collaboration and utilizing analytics to exponentially increased per-unit margins. However, as Benoit Lheureux, the VP for Research at Gartner points out, “IoT project implementers often ...
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, provided an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profession...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
When people aren’t talking about VMs and containers, they’re talking about serverless architecture. Serverless is about no maintenance. It means you are not worried about low-level infrastructural and operational details. An event-driven serverless platform is a great use case for IoT. In his session at @ThingsExpo, Animesh Singh, an STSM and Lead for IBM Cloud Platform and Infrastructure, will detail how to build a distributed serverless, polyglot, microservices framework using open source tec...
Connected devices and the industrial internet are growing exponentially every year with Cisco expecting 50 billion devices to be in operation by 2020. In this period of growth, location-based insights are becoming invaluable to many businesses as they adopt new connected technologies. Knowing when and where these devices connect from is critical for a number of scenarios in supply chain management, disaster management, emergency response, M2M, location marketing and more. In his session at @Th...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
"delaPlex is a software development company. We do team-based outsourcing development," explained Mark Rivers, COO and Co-founder of delaPlex Software, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
The idea of comparing data in motion (at the sensor level) to data at rest (in a Big Data server warehouse) with predictive analytics in the cloud is very appealing to the industrial IoT sector. The problem Big Data vendors have, however, is access to that data in motion at the sensor location. In his session at @ThingsExpo, Scott Allen, CMO of FreeWave, discussed how as IoT is increasingly adopted by industrial markets, there is going to be an increased demand for sensor data from the outermos...
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
Presidio has received the 2015 EMC Partner Services Quality Award from EMC Corporation for achieving outstanding service excellence and customer satisfaction as measured by the EMC Partner Services Quality (PSQ) program. Presidio was also honored as the 2015 EMC Americas Marketing Excellence Partner of the Year and 2015 Mid-Market East Partner of the Year. The EMC PSQ program is a project-specific survey program designed for partners with Service Partner designations to solicit customer feedbac...
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
There are several IoTs: the Industrial Internet, Consumer Wearables, Wearables and Healthcare, Supply Chains, and the movement toward Smart Grids, Cities, Regions, and Nations. There are competing communications standards every step of the way, a bewildering array of sensors and devices, and an entire world of competing data analytics platforms. To some this appears to be chaos. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Bradley Holt, Developer Advocate a...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...