Webcasting - Reach out Mobile platform

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ATI Chennai: Web Casting Solution to Mobile platform /i-pad / Tablet / Smart TV


  • Webcast is a media presentation distributed over the Internet using streaming media technology to dissseminate a single source content si,ultaneously to many listeners/viewers. A webcast may either be distributed live or on demand. Essentially, webcasting is broadcasting over the Internet.
  • Webcasting is used extensively in the commercial sector for
    • Investor relations presentations (such as in Annual General Meetings)
    • e-learning (to transmit seminars) and for related communications activities.

However, webcasting does not bear much, if any, relationship to web conferencing, which is designed for many-to-many interaction or webinar - bi-directional interaction with text chat.

What Are Some of the Challenges That a Webcast Can Face?

  • Your presentation can be boring, confusing, or just badly prepared.
  • Your delivery can fail as:
    • Viewers at the office can have a very different experience than users at home or on the road.
    • Users can have trouble viewing on mobile devices.
    • Your broadcast can have low quality.
    • Your broadcast can look great—until the feed drops or pauses to buffer.
    • Your broadcast can be high quality and reliable, but cause bottlenecks that slow down or stop everything else in your network.
    • You can exceed the maximum number of concurrent users on your plan.
    • You can produce a great event, but then have trouble transitioning the webcast from live to VOD because your video solution is siloed across multiple use cases and departments.
    • You can have a great recording that no one can find or access.

Commercial Webcast Service Providers

  • There are many key players for providing the webcast services and web conferencing in the market on payment basis.
  • Open Source Tools (free) are also available with limited features.

Webcasting vs. Web Conferencing

  • Vendors and end users alike have trouble in differentiating between webcasting and web conferencing.


  • A webcast is like a broadcast. It is usually one person, or multiple people giving a presentation. There is no interaction from the online audience who can be listening or watching video of the webcast. The best example is to think of it like a radio/TV station broadcast over the internet or a television.
  • Ideal for engaging larger online audiences and is a “one-to-many” (one speaker—or panel of speakers - presenting to many attendees) broadcast over the internet which can accommodate thousands of simultaneous viewers.

Benefits of a Webcast include

  • Repeatability: It can be played over multiple times on demand.
  • Shareability: The first audience isn’t the only audience. Because webcasts can be repeated, attendees can share the cast with friends or colleagues.
  • No scheduling of attendees necessary.
  • Webcasts can be to larger audiences and can be recorded and replayed



  • Online web conferencing allows for interaction between presenters and attendees. Different settings can be enabled to allow conference members to take turns speaking and sharing information.
  • Ideal for smaller, “few to few ” collaborative (interactive) meetings where most, if not all participants are communicating

Benefits of Web Conferences

  • Closed, intimate setting
  • Controlled environment (limited audience)
  • Time saver


ATI Chennai Infrastructure

  • ATI Chennai has been already equipped with a Server and necessary software for Distance Learning Programme (DLP)

ATI Chennai Cloud

  • An indigenous Cloud Data Centre deployed inb Open Source.
  • Fully Secured with Military Grade Open source firewall
  • Can be Deployed with Windows, DOS, Linux (Debian, CentOS, etc) and be virtualised with shared and dedicated kernel

Distance Learning Programme

  • ATI Chennai Media Server running on our Cloud acts as an Interactive Media Server which connects 10 Central Funded Institutes (CFI - ATIs/CSTARI/NVTI) as HUB (to decimate the contents in regional language) and 193 Govt ITI's across the country as Spokes in a interactive manner (two way communication) through internet.
  • Since many places, internet connectivity are not really reliable, Hence the department is on the way for implementation of Satellite Interactive Terminal (DTH) around 688 districts across the country and also a DTH channel for SKILL INDIA TV and the project is expected to complete by Dec 2017.



  • The Interactive Media Server has been powered by Aview software developed Amrita e-Learning Lab, Kerala (MHRD Project)
  • The Interaction can be visualized only through Desktop/Laptop computer which supports Adobe Flash Player.
  • Now-a-days, most of the students have smart phone with 3G/4G/WIFI network capability.
  • If we stream the live lectures and the e-learning content to the mobile devices also means, can reach the students much more.
  • Interaction can be enabled through text chat via free SMS through a toll-free number or social media like 'Whatsapp.
  • Hence, efforts has been made to configure the exiting DLP server ingenuously by our-self as Webcasting service as additional feature to reach-out mobile user.

ATI Chennai Webcast Service Initiative

Components of Webcast Service

  • To enable a webcasting service, it requires three major components apart from server hardware

1. Live Streaming Media Encoder
Encoding software allows you to capture content, including your desktop, camera, microphone, and more, and send it to the Media server to be streamed to all your clients.
In our case: we used Adobe Live Flash Encoder for video and audio source and OBS studio for Desktop sharing(free tools).

2. Streaming Media Server
Media Server is a hub which receives video/audio data from the live encoder through Real Time Messaging Protocol (RTMP) and in turn it can send and receive data to and from the connected users with the web player (normally web browser which supports flash playback) installed in the client system Most of the case the communication protocol used is RTMP which requires adobe flash player.
Media Server used : Adobe Media Server 5.0 professional

3. Web player
Normally any desktop browser like Mozilla Firefox, Google Chrome which supports adobe flash player plug-in

Web archi.jpg

Mobile Webcasting

Constrains in Mobile webcast

  • The Real Time Media Protocol (RTMP) used by Adobe Media Server renders in Flash mode and requires Flash for playback. Mobile devices don’t natively support Flash, that is why we can't play on mobile unless specific player is installed as APP on the mobile.
  • Streaming video on mobile devices remains one of the most challenging and frustrating experiences for viewers and broadcasters alike.
  • Moreover RTMP packets may have difficulties getting through certain firewalls which used special TCP/UPD port:1935.
  • Major advantage of RTMP is very low latency time in the order milli second

HLS streaming for Mobile

  • When HTTP Live Streaming (HLS)[3] was introduced, the goal was simple: easily stream live and on-demand video content to devices with a variety of bandwidth connections.
  • Adaptive streaming is a process that adjusts the quality of a video delivered to a web page based on changing network conditions to ensure the best possible viewer experience.
  • Adaptive streaming is the marquee feature of HLS, and while Adobe’s RTMP can offer similar capabilities in Flash, desktop browsers like Chrome and Firefox can play HLS streams using a player like the JW Player.
  • Adaptive streaming may be the single most important capability for delivering the optimum quality of service to a diverse range of viewers because of wide variation in internet bandwidth 3G/4G-LTE/WIFI etc.


  • HLS is enhanced further by native implementations found within Safari and iOS, which makes streaming to mobile devices even easier.
  • While HTTP Live Streaming was designed to deal efficiently with multiple quality streams, it wasn’t built for delivering video quickly. Practically speaking, HLS introduces at least 20 seconds of latency (often more!) in the streams.
  • HLS requires three segments in queue before it will allow playback, and the segments are divided by the keyframes in the video. The only way to create a super low latency stream (let’s say under one second) with HLS is to encode the video going out with a keyframe happening every 250 ms. The HLS playlist moving-window would be four items long with a segment duration of quarter of a second. This would of course create high bandwidth video, add to the number of HTTP calls happening (at least four per second), and put additional load on the server.
  • Another advantage of use for HLS steaming in mobile device is No Specific APP is required for mobile device as the HLS being the native implementation in the browser of mobile phones. So the streaming video/audio in the HLS can be directly displayed /played in the Mobile.

Trasnsport stream.jpg

Mobile Webcast Implementation

  • The Adobe Media Server with Apache web server built-in installed has been configured to enable HLS streaming with adaptive bit rating at three different rates.


Adobe Media Server Configuration File Details

  • The adaptive bit rating configuration file has been generated using the Tools pre-installed in the Adobe Media Server "F4M configurator" file. The sample config file at three different bitrate 150,500 and 1000 kpbs.
  • Save the file as 'liveevent.m3u8' in the webroot folder.

Note : replace the term "streamkey" with the actual streamkey used for streaming

  • Adobe Live Media Encoder used to stream the video/audio has been configured to stream the data using 3 different bit rate (say. 150,500,1000)


  • To facilitate our streaming service deployment in the browser, The HLS media player by http://www.vodobox.com has been used (as embedded code in the index.html) which can adapt itself automatically with any current Web environment. The video content is playable on computers, smartphones and tablets simultaneously with a same browser.
  • For Desktop Mirroring, OBS Studio has been used as streaming encoder.


  • We can directly stream the live video/audio from Mobile itself using native camera and mic with any RTMP Streamer Apps available in the Apple Store or Google Play store directly to our Adobe Media Server installed on the ATI Cloud with the streaming url rtmp://live.atichennai.org.in/livepkgr and with a streaming key [for streaming key, contact SysAdmin @ jp_ati@vsnl.net].

Mobile stream.jpg

  • The main drawback of webcast is unidirectional i.e One to Many - One presentor and multiple viewer. But viewer can't interact with the presentor.
  • To enable text chat feature during question answer time, Social media app, Whatsapp can be used for chating. Whatsapp.jpg


Test Results

The Process has been tested in various mobile devices like iphone, Android (different version), IPad, Notebook, Smart Tv, Laptop and Desktop etc in different geographical region and different network connection.

  • The quality of audio and video seems to be very good.
  • But the initial loading time for caching the video takes 7-10 sec
  • The latency observed was around 30 sec due to HLS protocol.
  • By keeping all the recorded videos of live session and e-Learning content, through Video-on-Demand (VOD) like "youtube, "we can allow the ITI students to access the content at any time (Learn from Home).

Mobile tab.JPG

Live jp.jpg

Reference Links

  1. Prerequisites for Live Streaming
  2. How to Setup Private RTMP Encoder using nginx opensource
  3. Technical Info on HLS Live Streaming
  4. Setting up Live Streaming using Nginx on ubuntu
  5. What Adobe Media Server can do - faq
  6. Overview of HDP and HLS Streaming with steps
  7. Adobe Live Encoder Setup
  8. Details on Flash Live Encoder Steps
  9. Youtube tutorial on mulitbit Streaming
  10. Configuring HDS and HLS Streaming
  11. Apple Notes of HLS streaming
  12. Media Cleaning Up after streaming is over
  13. Application shutdown on un-publishing the live event
  14. Multiplatform player from http://vodobox.com
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