Kamis, 22 Desember 2011

About HTML5

About HTML5 - Let’s start with HTML5, which has one potential show stopper for many houses of worship: the lack of a live capability. Apple has a proprietary technology called HTTP Live Streaming that you can use to deliver to iDevices and Macs but not Windows computers. So if live video is a requirement, HTML5 is out—at least for the time being.

If on-demand video is your sole requirement, HTML5 is a tale of two marketplaces: desktops and mobile. By way of background, HTML5-compatible browsers don’t require plug-ins like Flash or Silverlight to play web video. Instead, they rely on players that are actually incorporated into and shipped with the browser. Integrating video into a webpage for HTML5 playback uses a simple tag rather than a complicated text string to call a plug-in.

Today, the installed base of HTML5-compatible browsers on desktop computer is only around 60 percent, which makes it an incomplete solution, particularly for houses of worship whose older parishioners may be technology laggards who don’t quickly upgrade to new browsers. However, in the link that you use to display your video, it’s simple to query the browser used by the viewer to test for HTML5-playback capabilities. If the viewer’s browser is HTML5-compatible, the video will play in the HTML5 player. If not, you can code the page to “fall back” to the existing Flash Player or other plug-in, which will then load and play normally. While this sounds complicated, Flash fallback is totally transparent to the viewer and occurs in just a millisecond or two.

Why HTML5 first? Because as we’ll see in a moment, this is a very solid strategy for supporting Apple and Android devices. However, before jumping in, keep in mind that HTML5 is not as mature as Flash in several important respects. First, it lacks true streaming, or the ability to meter out video as it’s played, which is more efficient than progressive download. HTML5 also can’t adaptively stream or dynamically distribute multiple streams to your target viewers to best suit their connection speed and CPU power. It’s these two issues that the aforementioned DASH standard hopes to address.

However, the DASH standard doesn’t address HTML5’s biggest implementation hurdle, which is that all HTML5 browsers don’t support a single compression technology or codec. Specifically, Microsoft’s Internet Explorer 9 and Apple Safari include an HTML5 player for the H.264 codec, while Mozilla Firefox and the Opera browser support only Google’s open-source codec, WebM. Today, Google Chrome browser includes both codecs, but Google has stated that they intend to remove the H.264 codec sometime in the future. It’s actually a bit worse than this sounds because Firefox version 3.6, which is still more than 5 percent of the installed base of desktop browsers, only supports a third codec, Ogg Theora.

To fully support the universe of HTML5-compatible browsers, you’d have to encode files in three formats and still fall back to Flash for viewers without HTML5-compatible browsers. Or you could just continue to solely support Flash and wait a year or two (or more) until the penetration rate of HTML5 browsers exceeds 95 percent, and then reevaluate.

If your only concern was desktop players, this might be a good strategy. Include mobile in the equation, however, and creating an HTML5 player with fallback to Flash might be a great strategy for your on-demand streams.

About HTML5 Rating: 4.5 Diposkan Oleh: Unknown

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