Streaming Digital Media for E-Learning 3: Using a Dedicated Media Server

According to Adobe, organizations use streaming media for corporate communications, electronic learning, and sales & marketing.

In a learning context, streaming media technology is a central component of

• Delivering remote presentations to employees, customers, and partners
• Delivering asynchronous (on-demand) just-in-time training
  Providing delta training to upskill workers
• Enhancing professional development via VLEs/PLEs and mentoring programs
• Capturing tacit knowledge from experts for distribution to their colleagues
• Conducting pre-sales demos
• Providing customer service

According to the eLearning Guild (Marks, 2002) e-learning using streaming media can save you money, increase learner participation, and improve motivation and focus (p.2).

So let's take a closer look at content delivery via a streaming media server. When using a streaming media server approach, the initial production, post-production, and content encoding steps are undertaken in the same manner as for progressive downloading and HTTP streaming. However, at the distribution stage, the compressed media file is placed on a specialized streaming media server. A Web page with a reference to the media file is placed on a regular HTTP server 'front end' web page .

The rest of the streaming media server delivery process differs significantly from the web server approach. In contrast to the HTTP/TCP methodology used in web server streaming, the digital media file data is actively and intelligently sent to the client. This means that the media server delivers the content at the data rate associated with the compressed audio and video streams. The server and the client communicated during the content delivery process, and the streaming media server can respond to any feedback from the client (see Figure 1).

Figure 1 UDP and RTP/RTSP protocols

While streaming media servers can use the HTTP/TCP protocols used by Web servers, they can also use specialized protocols such as the User Datagram Protocol (UDP) and Real Time Streaming Protocol (RTSP) to greatly enhance the quality of the streamed content and ultimately the users' media access experience.

UDP is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages called datagrams to other hosts on an Internet Protocol (IP) network without requiring prior communications to set up special transmission channels or data paths.

Unlike TCP, UDP is a fast, lightweight protocol. This makes UDP an ideal protocol for transmitting real-time digital media data, which can tolerate some lost packets. Instead of the blind retransmission scheme employed by TCP, streaming media servers' resend feature ensures that the server only retransmits lost packets that can be sent to the client in time to get played.

Like UDP, the Real Time Streaming Protocol (RTSP) takes advantage of streaming by breaking data into many packets, sized according to the bandwidth available between client and server. When enough packets have been received by the client, the user's software can begin viewing the content: typically one packet is played, while subsequent packets are decompressed and downloaded. The advantage of RTSP is that it enables the user to start viewing multimedia content almost immediately. Both live data feeds and stored clips can be used as the sources of the content. The transmission of streaming data itself is not a task of the RTSP protocol; most RTSP servers use the Real-time Transport Protocol (RTP) for media stream delivery, though some vendors implement proprietary transport protocols. The RTSP server from adobe Systems, for example, also features their proprietary RTMP stream transport protocol.

RTSP has been called a "network remote control" for multimedia servers, in that the user can typically play, pause, rewind, scrub through (rewind and fast-forward), record, and stop playback via client interactions with the streaming server. Examples of media server products using this approach include:

• Flash Media Server family
• Microsoft Windows Media Services
• Apple Darwin Streaming Server
• RealMedia Helix Server

In a sense, RTSP is more of a framework than a protocol. It's meant to control multiple delivery sessions, provide a way to choose delivery channels such as UDP, TCP and IP-multicast. The delivery mechanisms are based solely on RTP. RTSP has been designed sit on top of RTP to facilitate both control and synchronous delivery of content.
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References:

Adobe Dynamics Group (2001). A Streaming Media Primer. [Internet] Available from: http://www.adobe.com/products/aftereffects/pdfs/AdobeStr.pdf Accessed 4 July 2009

Marks, R.B. (2002). Learning Styles and Streaming Media. The eLearning Developers Journal, October. [Internet] Available from: http://www.elearningguild.com/articles/abstracts/index.cfm?id=43&action=viewonly [Subscription Required). Accessed 3 July 2009.

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Streaming Digital Media for E-Learning 2: Delivering Content via a Web Server

Deploying streaming media content with the web server approach is very similar to the download-and-play model I described in yesterday's post: it's a pull technology.

Using this paradigm, the initial request for data originates from the client, and then is responded to by the server. When using digital media, uncompressed audio and video is first compressed into a single, muxed (multiplexed) media file for delivery over the Internet or a network at a specific bit rate. The media file is then placed on a regular web server. A web page containing the media file's URL is also created and placed on the same web server. When the link on the web page is clicked on, a client-side player (such a Windows Media Player or QuickTime Player) downloads and plays the requested media file.

In the context of e-learning, it's pretty standard for a video demo (for example) to be stored and progressively streamed from a Moodle LMS running on an Apache such as Apache server (see Figure 1)

Figure 1. Demonstration: Uploading a WMV file to Moodle, and playback via HTTP streaming in Windows Media Player
[Click to play the demo]

From a user's perspective, this process looks and feels identical a download-and-play case use case. From a technical point of view, the difference lies in how the client functions.

Unlike the download-and-play model, the client player starts actually starts playing the streamed digital media file while it's being downloaded. This is possible because the content is cached: a process of collecting the first part of a media file before playing. This small 'buffer' of information allows the content to continue playing even during periods of high network congestion. With this delivery method, the client retrieves data as fast as the Web server, network and client will allow, regardless of the quality of the compressed stream. Only certain media file formats support this type of progressive playback including Microsoft's Windows Media format (WMV) and Apple's QuickTime (MOV).

Web server streaming uses the Hyper Text Transport Protocol (HTTP), the standard Web protocol used by all Web servers and Web browsers for communication between the server and the client. HTTP operates on top of the Transmission Control Protocol (TCP), which handles all the data transfers.

It's useful to remember that HTTP/TCP is optimized for asynchronous, static applications, such as displaying static Web pages, and file transfer; this can affect the distribution and delivery of motion-based, asynchronous ('on-demand') content. Users may experience interruptions, 'glitches,' and temporary loss of playback because to the limitations of the HTTP and TCP protocols when handling multimedia content.

More...

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Streaming Media for E-Learning: A Primer

I'm preparing a series of blog articles on the topic E-Learning Using Collaboration Platforms. In the series I will discuss:

• Collaboration Platform Technology
• Synchronous Delivery
• Asynchronous Delivery
  
• Overview of Products on the Market
  
• Production Considerations
  
• What works (and what doesn't work)
  
• The Online Instructor
  
• Mentoring
• Integrating Collaboration Solutions and Other E-Learning Channels

This is an area of technology in education that I'm especially interested in, so I'm really looking forward to bringing this set of blog posts to you here on the E-Learning Curve Blog. As the series is still under development, there's an opportunity to request an article on an aspect of this topic that you might like to see covered: let me know and I'll see what I can do.

In the meantime, I thought I'd give you a 'heads up' by discussing some of the fundamentals surrounding using collaboration solutions: streaming media.

Until about five years ago, Web-based audio and video - or digital - media was primarily a download-and-play technology. Users had to download an entire media file before it could be played back. If you're over 30, you'll remember those postage stamp-sized video clips (usually in ASF or MOV format) that took forever to load over your dial-up connection (and were hardly worth the wait). Because digital media files are usually very large and take a long time to download, the only content found on the Web was short, low motion clips. Even these files could take 20 minutes or longer to download.

How video used to look and sound – Marc J. Rosenberg discusses personalized learning
[Click to play video]

With the increasing availability of high-speed internet access, streaming digital media has become more prevalent. In the consumer market, this has led to the rise in popularity of services like YouTube, and the current emergence of video-on-demand (VOD) solutions like Hulu, as well as ustream and for lifecasting and live video streaming of events online.

Streaming media works almost instantaneously: other than a short delay before the requested file starts to play, you don't have to wait to start watching, no matter if the file lasts thirty seconds or thirty minutes in duration.

Broadly speaking, there are two way of delivering streaming digital media content over the Web. The first method uses a standard HTTP Web server to deliver the audio and video data to a media player. The second approach uses a separate streaming media server designed specifically to stream digital media. Using a streaming server is more efficient and flexible, provides a better user experience, and is more secure than HTTP streaming.

Both approaches have their advantages and disadvantages, and I will begin to look at these tomorrow.

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Rapid E-Learning Production - Supporting Applications

As we know, Rapid E-Learning is subject matter expert-centric, based on authoring or developing content with easy-to-use, ubiquitous platforms like PowerPoint & Flash, and enables content to be developed in a matter of days, not than weeks or months. Rapid e-learning does not mean taking liberties with well-established content development processes.

Rather, it is an approach to content development that enables SMEs to author content quickly and efficiently, typically using learning professionals as coaches and assistants in the process.

The two tenets of rapid e-learning are:

1. Ease of development
2. Short development time frames

The key to successful rapid e-learning is having tools and templates that make it easy for practically any expert to quickly create effective learning materials.

However, rapid content authoring is only part of the story. The end-to-end content design, development, delivery, management and maintenance cycle demands a broad range of skills (I talked about some of these here), and a number of computer applications to support and leverage these steps of the e-learning development process.

In my never-ending pursuit of enhancing performance when using the Rapid E-Learning methodology, I regularly assess new applications, tools, and utilities to assess their value in my learning and development content production procedures. Here are the applications I’m going to evaluate over the next few months. Of course, I’ll blog my views on them over that period of time. Interestingly, only a few of these apps are 'pure' e-learning development tools; the others I intend to use to facilitate aspects of the content development process, rather than to actually develop learning materials.

Serena Prototype Composer 2009
Serena Prototype Composer is an application planning, modeling and prototyping environment for non-technical users to visually define their application needs, including business processes, activities, user interfaces, requirements, and data. Models can be derived from existing resources such as Web applications and can be published as running prototypes as well as Microsoft Word specifications.

WebCAT
The Web Category Analysis Tool is an open source utility that allows designers and usability engineer to test a proposed or existing website or CMS/LMS ontology or categorization scheme. This enables knowledge managers (and instructional designers) to determine how well taxonomies, categories and learning content objects are understood by users. WebCAT is a variation on the traditional card sorting paradigm, where users are guided to generate a category tree or even a folksonomy.

Stanza Desktop
Stanza Desktop is an e-book publishing tool, designed for generate digital publications, including electronic books, newspapers, PDFs, and general Web content for a range of hardware platforms. It supports HTML, PDF, Microsoft Word, and Rich Text Format reading, as well as all the major e-book standards: unprotected Amazon Kindle and Mobipocket, Microsoft LIT, Palm doc, and the International Digital Publishing Forum's new EPUB Open eBook standard. According to the developers, Stanza is designed to to make reading on your Macintosh, PC or mobile device an “enjoyable and hassle-free” experience.

iWebkit
iWebKit is a GNU-licensed file package and content framework designed to enable those without the time or the programming skills to use the iPhone SDK to create iPhone and iPod Touch compatible websites and webapps. According to the developers, the kit is accessible to anyone - even people without any html knowledge. and is simple to understand thanks to the included tutorials. We’ll see.

Microsoft Learning Content Development System
The Microsoft Learning Content Development System (LCDS) is a free-to-use tool that enables the developers to create interactive, online courses. The LCDS allows anyone to publish e-learning courses by completing the easy-to-use LCDS forms that seamlessly generate highly customized content, interactive activities, quizzes, games, assessments, animations, demos, and other multimedia.

PowerManual
PowerManual addresses the needs of presenters, trainers and anyone who uses PowerPoint on a regular basis. PowerManual enables you to produce high quality documents in a range of formats, including Word, PDF and HTML.PowerManual enables the creation of cover pages, logos, custom headers and footers, document pagination, on-the-fly slide updating, as well as PowerPoint slidestack management.

As I said, I'll be reviewing the apps, testing and reporting on their functionality, ease-of-use, suitability of purpose, adaptability to e-learning, and so on. I’d like to hear your opinions: do you already use some or all of these tools? What do you think of them? Are you going to evaluate them yourself, based on my suggestion? Are there any other tools in the same space that are more effective?

Let me know what you think by commenting in the space below.

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