By Nathan Willis on April 01, 2008 (11:30:00 AM)
PILTDOWN, UK - High definition HTML is coming to a site near you -- whether you will see it is another matter. An addition to the HTML5 working draft specification was approved by the World Wide Web Consortium (W3C) working group over the weekend, including several new HTML elements and attributes designed to support output on high definition displays. But due to patent protection, open source Web browsers may not be allowed to implement a significant portion of the standard.
The W3C's HTML working group added the extension set to its Second Public Working Draft of the spec, published Sunday. The HD extension introduces one new head-level HTML/XHTML element, three block-level elements, four global attributes (which can be used with existing elements), and three additional attributes unique to the previously-approved
element.
, the HD HTML extensions are not related to the video element codec controversy from last December, in which representatives from Apple and Nokia objected to the inclusion of the open and patent-free Vorbis and Theora codecs to the HTML5 spec. According to the published draft, the high definition HTML additions will permit designers and Web app developers to "design rich media sites that take better advantage of high-resolution display technology" and the "improved visual and auditory capabilities" of modern hardware, including both high-def, deep color PC monitors and non-PC displays like home theater.
, which specifies the height and width of the document, using relative or absolute units, or as a percentage of the containing window. The draft spec states that a browser should re-size the window to display the correct resolution if possible, and must scale the document to fit if the specified resolution is larger than is physically available. The element can optionally indicate whether the display of the document should be interlaced or progressive, a feature not likely to impact Web pages viewed on traditional PC and laptop displays, all of which are progressive-scan.
, , and . Content enclosed within a ... tag pair can be rendered inline in the page or, when possible, piped to another display -- whether a physical device or another software program. A ... block can contain its own head elements, like resolution.
element is similar in the sense that it delimits content to be send to another display, but an block cannot be rendered in-line. The example given in the spec specifically lists as a case which could take advantage of the High-bandwidth Digital Content Protection (HDCP)-capable copy attribute to prevent display of its contents on unauthorized devices.
element is essentially a duplicate of the requires colorspace=, dynrange=, and gamut= attributes, without which it may not display properly on the page.
s or links.
element gains an additional three element-specific attributes in addition to those above. The trailer= attribute allows the specification of an external file or URI to be used as a video trailer for the full-length content of the element. The encoding= element refers not to the codec used, but to the color model of the enclosed video -- YUV, YPbPr, YCbCr, YIQ, or unknown. The ticket= element can be any of the literal strings "free," "rental," "temporary," or "purchase." The "rental" and "purchase" values are meant to function in concert with an authorization method such as the copy attribute; in the absence of an authorization method, the specification says that the User agent (i.e., browser) "shall not" display the content. A fourth element-specific attribute, intermission= was proposed, but failed to pass.
and tags.
element and floating-point values for block level content and CSS elements are a substantial upgrade over today's HTML. All high-resolution displays -- including the HDTV formats of today and the in-progress formats still years from reaching the market -- will benefit from the ability to accurately place content on the screen to sub-pixel resolution. Sharper fonts, sharper graphics, and sharper auto-generated JavaScript content.
can send commands to operate remote-controlled home theater components, dim room lighting, and mute other audio devices and telephones. Because the protocols involved are open, free software browsers could be the first to implement these features.
No comments:
Post a Comment