High-Definition Video on the Internet from Akamai

HDTV is defined by the industry to be video with significantly high pixel resolution of 1080i, 1080p or 720p. With the world increasingly moving to HD, Akamai’s delivery of HD content is in direct response to a growing consumer audience for large, long-format files thanks to the evolution of broadband and the demands of businesses when it comes to software downloads. 

Broadband subscribers are guaranteed to have a faster download, and enjoy a quality HD experience, when downloading content from servers nearby the request.  With servers distributed in over 750 cities, Akamai addresses these technology requirements with its unique edge delivery model that reduces latency to levels necessary for a quality HD experience.  Because distance matters for high-quality large files, all content, whether it is frequently or rarely requested, must be served closest to the end user.  Akamai’s unique technology automatically and instantly spreads popular content on-demand for better scalability.

In addition, many large HD videos are not always watched in their entirety.  It is therefore optimal to locally cache only the portion of a file that is most requested by end users, which on average is the beginning of the file or movie.  This partial caching of HD video enables both popular and less popular, long-tail content to be served from the edge to guarantee optimal performance.

To realize this same vision and fidelity in the online world, a 2-hour feature-length movie would need to be encoded at a bit rate of at least 6-8 Mbps, which would result in the file being a size of 5-8 GB.  This presents numerous technical challenges to deliver such a high-quality, large file.  For instance, delivering a file encoded at 6 Mbps to an audience of one Nielsen ratings point (1,102,000 households) would require 6.6 Terabits of sustained bandwidth, and that doesn’t even take into account latency and network congestion.

The availability of very large, last-mile bandwidth connections does not always mean that an end user will be able to completely leverage that access.  A critical factor to enable high bit rate delivery of very large HD files is the proximity of the end-user to the server sending the file.  As the distance from the server becomes greater, throughput dramatically decreases.  Even a seemingly small distance can result in lost throughput due to lower throughput, higher packet loss, and increased latency.  

As an example, the only way to achieve 10 to 20 Mbps throughput for typical PC end-users is if the server is less than 20 milliseconds away.  The more latency, the longer it takes to download the file, which interrupts the viewing experience and results in a poor end-user experience.  Compared with other centralized models, the results that Akamai’s network offers high quality content are unmatched on a global scale.