Defining Standards for Web Media Delivery: A Case Study

For eleven years, CCNMTL has provided cutting-edge media services for courses and projects at Columbia University. Our media services initially relied heavily on streaming media (via RealMedia and QuickTime servers), but we have come to favor downloadable media (in the form of HTML5 and Flash-based platforms). In either case, many production requests have been handled on an ad hoc basis using a set of loose guidelines, which lead to arbitrary decisions about frame size, bandwidth use, and encoding formats based on the exigencies of the project or task at hand.

We knew we needed a comprehensive set of guidelines in order to maintain a high level of service and flexibilityAs the demand for media production services has grown, we knew we needed a comprehensive set of guidelines in order to maintain a high level of service and flexibility. In the fall of 2009, CCNMTL's digital media staff began to review existing practices with the goal of assembling a set of guidelines that would stabilize our media production decisions and provide reasoned structure to our media delivery practices.

Of course, determining a consistent set of production and delivery practices is always challenging when media formats and features within web browsers and mobile devices are changing constantly, so special attention was given to create flexible and extensible guidelines that worked over time and across platforms and devices.

Requirements and Models for Effective Media Delivery

Our staff considered a wide range of sources and references during the review, including:

  • web standards and best practices adopted by academic and commercial media groups
  • forecasts of web media technologies directions based on staff's extensive expertise
  • video encoding profiles and file formats used in previous CCNMTL projects
  • existing media platforms such as iTunes U and YouTube

As we developed a platform for Columbia-hosted course and project media delivery, we hoped to emulate platforms like iTunes U and YouTube because they are available to Columbia faculty and they have raised users' expectations about easy-to-use environments that feature simple playback and sharing options as well as tools to embed, tag, and comment on media.

Our guidelines also aimed to address three major technical questions:

  • What are our use cases? How can those be categorized?
  • Which media format best fits each use case?
  • What in-browser player best accommodates these formats?

First, we developed three distinct categories of use which allowed us to minimize the number of media formats we produce and highlight cases where media format requirements converge. For example, since the same media format can be used in both a web page and a podcast, we have one fewer specification to define.

Category/Type of media requestExamples
Basic mediaMedia embedded on a public web page, public-facing project environment, or course web page; Media available via RSS (podcast);
Media intended to be hosted on iTunes U or YouTube.
Secure mediaMedia embedded on a private web page or private project site; Media that has copyright restrictions, but is being used in a course site under fair use.
Time-based mediaMedia contained in a playlist or that depends on timed annotations or chapters.

Second, we needed guidelines to define an individual media format and file type to be used depending on the use case. Our staff reviewed many media formats, media file types, and their related (in)compatibilities.

We found that MPEG-4-based file types (encoded with an H.264 format profile) provide the appropriate match for "basic" media requests. MP4 can be used on web pages using a variety of methods and it is supported by RSS specifications and most media platforms. MPEG-4 media is also currently supported on all modern mobile operating systems.

However, "secure" and "time-based" media require more precise compatibility between web servers and accompanying web software. In these latter categories we chose Adobe's Flash Video (.flv) file type despite the fact that Flash video is incompatible with many mobile devices.

Third, the guidelines define media plug-ins and media player elements with which to view the media. Currently, media players that use the Adobe Flash plug-in are the standard for browser-based media. Both MPEG-4 and FLV media formats can be viewed using Flash-based media players within the browser. We chose to support a popular, open source media player called Flowplayer (http://flowplayer.org/).

Since we hope to achieve a solution that will simultaneously cover as many use case categories as possible, we are experimenting with the HTML5 video tag. This development will allow us to support all browsers and mobile devices via one format and player.

With this in mind, our staff adapted an existing media embed code (http://camendesign.com/code/video_for_everybody) that provides support for both Flash and HTML5 depending on the playback environment. We adjusted this delivery technique further so that it also meets the needs of each type of media request. For instance, when a basic media request that uses MPEG-4 is viewed in a standard web browser, playback is provided using Flash-based media player. Alternatively, when the MPEG-4 media is viewed in a mobile browser, HTML5 provides the media playback features. Because some mobile systems only support HTML, secure and time-based media (e.g. Flash-based media) are not supported. However, the entire embed script can be updated centrally as new capabilities are added to desktop and mobile systems.

New Guidelines and Next Steps

So, our standards now support an updated set of media formats and plug-ins while also providing the capacity to refine support for both over time. In sum, our guidelines now provide a steady foundation for:

  • sustainable media standards that simplify production decisions
  • media that is compatible with numerous platforms with minimal duplication of effort
  • versatile media player support that addresses most requirements and is "future-proof"
Types of media requests: supported formats, file types, and plug-ins:


If the request is for:

Basic media

Secure media

Time-based media

and the intended playback environment is:

Web browser; Mobile device; RSS

Web browser only

Web browser only

then the media format used is:

MPEG-4

(H.264 encoding)

Flash Video

(Sorenson or On2 encoding)

Flash Video

(Sorenson or On2 encoding)

and the media file type used is:

.MP4 container

.FLV container

.FLV container

media playback plug-in supported:

Flash and HTML5

Flash

Flash

Because the population we serve at Columbia is diverse and our educational partners continue to grow outside of the University, it is important that the media formats used within our services are reliable regardless of the computing platform or web browser environment. It is also important to us that access to our wide range of educational resources are not encumbered by technical nuances. To insure continued improvements, CCNMTL plans to continually evaluate and refine these guidelines based on the strategic framework we developed to form them.

Our staff also recognizes that the challenge of improving and standardizing video services is one shared by many media and technology groups in education. Over time, we will continue to look to and collaborate with our peer institutions in determining and sharing the best practices and extensions of these standards.