Streaming Gets Smarter: Evaluating the Adaptive Streaming Technologies
For whatever reason, practically speaking, it appears that the benefit of cache servers is so unquantifiable that it is irrelevant. That is, while Flash streaming may be priced at a premium at some CDNs, this seems to relate more to technology license fees (discussed next) rather than any sense that RTMP is inherently less efficient than HTTP.
The sole exception may be Akamai, which is charging less for HTTP video delivery than non-HTTP streaming, including RTMP and other streaming protocols, according to an Oct. 3, 2008, post on Dan Rayburn’s Business of Video blog ("Why Is Akamai Charging More for Streaming Video Delivery Versus HTTP Delivery?"). However, Rayburn writes, "I don’t know of any other CDN in the market that is pricing video delivery this way and as a result, I see Akamai not winning a lot of new deals in the market."
I’m not dismissing the value of caching; in particular, for massive live event distribution such as the Obama inauguration, the efficiencies could be enormous. However, it doesn’t appear that these efficiencies translate into a direct cost benefit. Obviously, if you’re in the process of choosing between an HTTP and RTMP technology, pricing distribution using the different technologies with several CDNs would provide definitive input.
What about the QOS argument? Unfortunately, while serving cached data should provide a better experience than data delivered via the internet, it’s very challenging to quantify. In any event, the fact that Flash is used by multiple three-letter networks dictates against the conclusion that RTMP automatically translates to reduced QOS.
The Waning CDN Flash Tax
Finally, the third theoretical advantage of HTTP streaming is that it doesn’t require a persistent connection between the server and player, so you don’t need a streaming server to communicate with each viewer—any traditional web server will do. In contrast, RTMP streaming does require a persistent connection between server and player, meaning more streaming servers are required to reach the same number of customers. Since Adobe and its competitors charge for the Flash Media Server required for dynamic streaming, this increases the cost of streaming Flash over the other technologies.
Note that both Microsoft and Move require some server-based technology, but only a central server with plain-Jane HTTP servers interfacing with the clients and distributing the video data. Apple’s new adaptive bitrate streaming schema requires no Apple-related server technology at all.
Of course, for large companies acquiring servers for their own use, Adobe’s December 2007 price reduction from $5,000 to $995 for a dynamic-streaming-capable Flash Media Server dramatically lowered the pain levels associated with Flash streaming. While Adobe’s pricing structure with CDNs is more closely guarded, it’s clear that the premium many CDNs charged for Flash delivery is dropping in price and starting to disappear entirely, though the data is a bit dated, unfortunately.
Specifically, in a blog post dated Oct. 6, 2008 ("Most CDNs Still Charging More to Deliver Flash Streaming"), Rayburn reported that, for those CDNs that did charge extra, the premium was about "a penny per GB," which translated to about "an extra $1,000 a month for every 100TB of transfer."
In addition, Rayburn wrote, "The good news from all of this is that EdgeCast, Velocix, and Level 3 no longer charge any license fee for Flash streaming. Last year, all CDNs charged a license fee of some kind, so the fact that three CDNs in the FVSS [Flash Video Streaming Service] program are no longer charging customers for Flash streaming is a good thing. Over time, I expect more CDNs will join them in doing away with the license fee as they get more traffic on their networks and ramp up their services."
The True Cost of RTMP Streaming
The RTMP concept of a streaming server required for each viewer prompts scary thoughts of companies such as Akamai (not one of the CDNs I spoke with) being forced to buy or license a Flash Media Server for each of its reported 48,000 edge servers or simply choosing not to buy the servers and having inadequate resources to match Flash demand. However, in speaking with the two CDNs mentioned earlier, I learned that the server-related cost of supporting Flash was much less than anticipated.
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31 Dec 2010