2011年3月10日
By 迈克尔•戴尔开放媒体开发者，维基媒体
专题文章

HTML5视频导航

HTML5 has quickly transitioned from an ad hoc standards process into a widely adopted and highly visible platform for delivering rich media web experiences. We will look at key developments that shaped the HTML5 platform and how HTML5 is playing an increasingly critical role in organizations' online media presence. We will also highlight many practical and technical resources to help navigate HTML5 video for use in your organization or software platform. 最后，我们来看看2011年我们可以期待的发展.

HTML5，一段简短的历史:在乔布斯之前

Much has been said about Steve Jobs' "crusade" against Adobe as the primary mover of an entire online video industry toward reluctantly supporting a non-Flash platform. 事实上, the shift is part of a much broader industry transition toward commoditization of core web technologies that started before Jobs became one of its biggest advocates.

为了理解HTML5的迅速普及，我们有必要回顾一下它的历史. 马克·皮尔格林的书探究HTML5 提供了一些很好的见解. 总结, in 2004 at the W3C (World Wide Web Consortium) workshop on Web Applications and Compound Documents, Mozilla和歌剧合作概述了他们对HTML未来扩展的愿景. The meeting established that the W3C was not going to put any resources into extending HTML.

因此，一个独立的组织， WHATWG，有… 竞争的愿景为HTML的未来扩展建立了. This separate organization offered greater flexibility and an open process that was more agreeable to innovative evolution of the web application platform.

Among many other extensions to HTML, the video tag was proposed as part of the WHATWG efforts. 歌剧 was the first browser to ship experimental video tag support in November 2007. 随着HTML5开始引起业界的兴趣, the issue of a standard codec for the video tag became a highly contentious issue in the standard process. 另一个W3C研讨会，网络视频，发生在2007年12月. 在那里, open web video advocates argued that the HTML5 spec should specify a royalty-free baseline codec. 最终, 所有相关方无法就单一编解码器达成一致, 所以HTML5规范最终变成了编解码器无关的. (更多的 detail about codecs can be found in the practical guides included in this article.)

2008年年中, kaltura和Mozilla基金会, 耶鲁信息社会项目, 参与文化基金会成立开放视频联盟该组织帮助推动在线视频的开放标准. 该联盟每年举办一次公开视频会议. 大约在这个时候, 创作 also began working on a project to develop open collaborative video tools for Wikipedia based on the emerging HTML5 video specification.

HTML5起步

2010年1月, YouTube开始支持HTML5视频播放器, as by this time all the major browsers except Internet Explorer were shipping HTML5 video support.

2010年5月, 谷歌 announced the WebM project with the aim of gaining industry support for a royalty-free codec for the HTML5 standard.

2010年4月，史蒂夫·乔布斯在一篇文章中发表了他对Flash的看法公开信, which served as a clear industry marker that supporting HTML5 was going to be critical for reaching the hugely popular iOS devices and, 可能比其他任何事件都要多, 引发了整个行业的采纳.

大约在同一时间，微软表达了对HTML5平台的承诺. A 微软 general manager later went on to say, "The future of the web is HTML5."

因此，视频平台提供商做出了反应. Soon, many video platforms and video sharing sites began to flesh out their HTML5 support options.

创作了 Html5video.org, an industry resource for HTML5 video-related 信息 and home of 创作's open source collaboration with Wikimedia and Mozilla that delivers a robust, 高质量HTML5库. 最后, 2010年末, Adobe announced its entrance into the HTML5 playing field with its HTML5 Video Player widget based on 创作's HTML5 library.

就现实世界的采用而言，所有这些发展意味着什么? 2010年1月, the percentage of online video that was available via HTML5 was about 10%. 同年十月, 54%的在线视频支持HTML5, MeFeedia的一份报告称. 2011年，HTML5的应用将更加普及.

HTML5和Flash

One way of understanding the HTML5 platform is in terms of differentiation from the Flash Platform. 以下是两者之间的一些主要区别:

•单一供应商vs. many vendors-Within the Flash Platform, a single vendor (Adobe) controls the platform. 与HTML5, 许多不同的浏览器制造商(苹果), 谷歌, Mozilla, 歌剧, 微软, and more) support the standard to varying degrees across numerous desktop browser versions. Each company also has a mobile version(s) of its browser along with other mobile vendors (BlackBerry, 棕榈, Nokia) with various software versions across devices and mobile network carriers; this makes for a huge compatibility matrix. 一方面，一方面, HTML5是一个复杂的平台, 但另一方面, it contributes to a fast pace of innovation with interest and investment from a wide range of powerful forces in the industry.
• No DRM-Unlike with Flash or other media platforms, there are no cross-browser DRM solutions. 有一些技巧可以使复制内容稍微困难一些. 但总的来说，HTML5目前并不适合限制版权的内容. 这一情况预计将在2011年和未来得到改善.
•目前没有细粒度的网络控制, 在客户机上进行网络管理是很困难的, 也没有跨浏览器的自适应流媒体解决方案. (苹果iOS设备确实支持苹果的HTTP 在线直播.)
• Integrated solutions for advertising not as widely supported as in Flash-This is another area that is expected to greatly improve in 2011.
• Generally not as easy to plug and play third-party components with player frameworks-在那里 is no top-down OSMF (Adobe's Open Source Media Framework) that makes it easy to adapt plug-ins to players.
It's important to note that even given the above limitations, HTML5 has some advantages:
•结合更快的JavaScript引擎, CSS3, 以及现代浏览器的其他功能, rich interfaces can be built around HTML5 and can be leveraged across numerous platforms and devices.
• Numerous open source JavaScript libraries have emerged to help bridge gaps in HTML5 implementations.
• Forward-thinking content distribution companies such as Netflix have already started adopting HTML5 for their user interfaces and working to address the limitations of the video tag for distribution of their media content.
•HTML5将继续存在，并继续创造巨大的行业动力. It's hard to find an active browser vendor or mobile software platform that is not going to support HTML5.

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