https://www.w3.org/ - 2017年9月18日，为进一步实现促使Web成为媒体和娱乐一流平台这一目标，万维网联盟（World Wide Web Consortium，W3C）今天正式发布加密媒体扩展（Encrypted Media Extensions，EME）推荐标准（Web标准）。EME是一个应用编程接口（API），允许无插件播放Web浏览器中受保护（加密的）内容，它可以无缝地作用于所有主要的平台。W3C的媒体资源扩展标准（Media Source Extensions, MSE）提供传送媒体视频的API，而EME提供了处理加密内容的API。MES和EME的组合式当今最常见的做法，允许Web开发人员在不使用各类浏览器专用插件的情况下也可以通过Web提供商业级高品质的视频。
W3C全球项目负责人Philippe Le Hégaret表示：“在诸如Google, Microsoft, Netflix, Mozilla, Apple, CableLabs, Adobe等主要的公司和组织之间，作为W3C各会员组织间通力合作的一项直接结果，EME不但早已被广泛采用，而且在众多Web浏览器上也已进行了重大实现”。
在Web上观看电影和视频的观看体验，现在已经从繁琐且不安全的布局转移到安全性的开放Web平台。将EME API集成到开放Web平台，实现了Web浏览器与允许播放受保护内容的软件之间的通信。
EME对用户的益处
EME提供了更好的用户体验，为用户在Web上观看加密视频带来了更大的互操作性，更高的隐私与安全性，更多的可访问性辅助功能。
Philippe Le Hégaret 提到：“EME规范的开发过程中一直专注于用户安全性以及隐私性。与之前的可以观看Web视频的方式相比，EME的优点是所有的交互都发生在浏览器内部。EME将与加密媒体交互的责任从插件转到了浏览器，浏览器在此充当了真正的用户代理”。
保持在浏览器控制下的安全交互是EME的一个重要方面。EME推荐标准清楚地提请对以下安全和隐私威胁等重要性的关注，例如：网络攻击，非法追踪，设备端用户信息损害等。得益于EME在开发期间进行的广泛审阅，如今所有的安全和隐私需求都已记录在文档中的不同部分。此外，EME规范还提供了一个清晰的路线图，指出实现者该如何加强对Web用户的安全和隐私的保护。
之前当Web中的特性还不可用时人们还在大范围使用各类浏览器专用插件。之后开放Web平台的不断实现一个接一个地消除了这些插件。因而一些站点已经从插件迁移到了EME, 该标准将对站点迁移产生积极影响。Web的改进使得通过安装插件来播放视频的时代已经成为过去式。通过将所有的交互迁移到浏览器中，它们将免受插件安全漏洞的影响。同样的道理，Web开发人员不再需要使用外部插件编程环境所需的专有工具；他们现在可以一度开发他们的Web应用程序并在Web上进行部署。
EME仅仅是让用户更好地控制如何与受保护的内容进行交互，EME并不会创建，更不会要求数字版权管理（Digital Rights Managements, DRM）。EME也不要求任何特定内容解密模块（Content Decryption Module）实现，它只是确保支持明文公共秘钥系统，为浏览器提供一个共同的基准水平的功能。EME的一个优点是它可以在开源和免费软件浏览器中实现。此外，正如W3C所有标准一样，是否实现EME是完全自愿的。作为对开放Web平台的扩展，对HTML规则来说EME并非是必要的，浏览器也可以选择不执行。在这种情况下，浏览器将完全可以支持未加密的内容。
与现有机制相反，通过在不干扰可访问性信息的传输或控制的级别上进行操作，EME提升了对加密在线视频的可访问性。这是通过隔离播放受保护内容的功能，并将其集成到开放Web平台来实现的。W3C标准制定过程中包括无障碍可访问性审阅这一重要环节，以识别实现可访问性过程中的潜在障碍并鉴别无障碍辅助功能可以予以支持的新机会。W3C对EME的分析和测试没有显示存在访问字幕，录音，音频描述或视频等方面的障碍。符合EME的应用程序可以确保无障碍信息将以明确的方式传输；或者如果是被加密的话，那么则与主要视频文件一起解密。可以利用由HTML规范或其部分扩展所提供的所有相关功能，以及开放Web平台当前和未来可访问性的增强功能（阅读更多关于EME以及可访问性）。
EME在浏览器之间的大量互操作性已经被证明是规范开发的一部分。 EME不但确保了许多浏览器上视频内容的无缝播放，而且还可以从优秀及最先进的整个Web堆栈模型中获益。
有关该规范和历史信息或更多技术细节，请参阅W3C董事Tim Berners-Lee先生对EME的评论和决定，以及EME相关背景资料。
有关EME成为W3C标准的讨论
在经过众多利益相关方以及Web社区为期六年的共同努力，广泛的技术工作以及公开的讨论之后，W3C理事Tim Berners-Lee先生作出了推进EME成为W3C推荐标准的决定。
Tim Berners-Lee先生提到：“如果要观看加密的内容，与其下载应用，那么在可以提供安全和隐私的浏览器中观看将更加安全 。一个通用的Web必须具备各种内容，例如音频，视频，文本，互动，地图以及图形等。Web上的某些部分是免费的，有些则不是。可以理解的是，某些生产者并没有准备好在没有保护的情况下免费发布其投入巨大成本所生产的内容。如果我们要进行加密，与典型的DRM不同，EME的优点是保护用户不受攻击。
虽然有些人不同意W3C发布EME标准这一决定，但W3C确定，要在Web上观看视频的成千上万的用户（其中一些视频包含来自创作者的版权保护要求）应该能够以安全的方式在Web上进行进行观看。 针对会员7月中旬根据上诉程序（appeal process）所提出的申诉要求，W3C成员于9月中旬进行的正式表决中，共108位会员单位代表支持理事的决定同意将EME推动成W3C标准，57位代表反对，20位代表弃权。 欢迎参阅W3C首席执行官Jeff Jaffe的博客文章：关于EME讨论的反思。
流媒体服务的使用在全球呈指数级增长。 目前，数以亿计的用户受益于EME，例如基于用户订阅服务的Netflix，以及其他的提供观看加密视频内容的发布者。
关于万维网联盟（World Wide Web Consortium，简称W3C）
万维网联盟（World Wide Web Consortium，简称W3C）是由会员组织、全职工作人员、以及公众共同组成的致力于发展互联网标准的国际化组织。 W3C通过创立互联网标准及指导方针来保障互联网长期稳定的发展，开放万维网平台（Open Web Platform）是万维网联盟目前的核心工作。 W3C制定了包括 HTML5 、CSS 等构建Web站点与Web应用的基础技术协议，并因为在无障碍在线视频字幕等工作，获得2016年的艾美奖（2016 Emmy Award）。
W3C “一个万维网（One Web）”的理念吸引了全球400多家会员单位数千名技术专家共同工作，其中中国会员33家（其中大陆地区29家、港澳台地区4家）。W3C主要由如下机构联合管理：美国麻省理工学院计算机科技与人工智能实验室(MIT CSAIL)、法国的欧洲信息与数学研究联盟(ERCIM)、日本庆应大学(Keio University)以及中国北京航空航天大学(Beihang University)，并在全球范围内设有办事处。更多信息请见http://www.w3.org，及W3C中文网站 http://www.chinaw3c.org。
媒体联系人
Amy van der Hiel, W3C Media Relations Officier <[email protected]> 电话: +1.617.253.5628 (美国东部时间）
中国大陆、港澳台及其他华语地区，请联系 Xueyuan Jia, <[email protected]> 电话：+86.186.1297.0645
来自W3C会员的评论
CableLabs
As a member of the World Wide Web Consortium (W3C), CableLabs participated in the development of the Encrypted Media Extensions (EME) recommendation – in collaboration with other major W3C member companies – to help further its goal of making the web a first-class platform for media and entertainment. EME was developed with user security as a major goal, while also focusing on improving user experiences and facilitating seamless communication between web browsers and software that allows playback of protected content. CableLabs is glad to see EME achieve the status of W3C recommendation.
Ralph Brown, Senior Vice President and Chief Technology Officer
Consumer Technology Association (CTA)
The CTA WAVE Project congratulates the W3C for having published EME as a full W3C Recommendation.
CTA WAVE firmly believes in the importance of EME to the future of commercial video, an important contribution to the future of the web that enhances:
- Interoperability—With EME, commercial video is encoded and encrypted using open standards that are supported by different browsers and decryption systems;
- Accessibility—EME allows the media industry to deliver better and more interoperable accessibility features than was feasible with previous closed media delivery platforms;
- Next generation media—EME will enable many small, specialized providers to deliver commercial media over the web, with the potential of transforming the entertainment industry while continually expanding the horizons of the web in the 21st century.
The first document from the WAVE Project, the Web Media API Snapshot 2017 specification, was recently released for review within the Web Media API Community Group, and more specifications and documents leveraging and citing the work of W3C and other groups will follow soon. The Web Media API Snapshot 2017 specification is built around the W3C standard HTML5 video architecture, including Encrypted Media Extensions (EME) when supporting encrypted video.
CTA WAVE looks forward to continued collaboration with W3C and other stakeholders to ensure the web remains a premiere platform for enabling communication and innovation.
The CTA WAVE Project is an initiative by many of the most influential names in video and audio, comprising manufacturers, distributors, service and infrastructure suppliers and over-the-top commercial internet video providers to identify requirements and guidance on the use of those specifications. More than 60 companies and 150 engineers are currently working on this effort.
CTA WAVE Project Steering Committee
Microsoft Corporation
Microsoft congratulates W3C on completing the Encrypted Media Extensions Recommendation, and thanks Sir Tim Berners-Lee for the hard work and leadership he provided to bring it to conclusion. This, along with the publication of the Media Source Extensions Recommendation, marks an important milestone on the journey to leverage HTML5 standards to allow full-featured media playback in browsers without plugins. By using HTML5, MSE, and EME, developers can add video features using just standard formats and APIs, and websites can count on browsers to deliver media without having to support 3rd party plugins. Users can be confident that their chosen media content is delivered in an accessible, secure and privacy-respecting way.
Jason Weber, Director of Program Management, Web Platform R&D
Motion Picture Association of America (MPAA)
Consumers today have access to more creative content across more digital platforms than ever before. In 2016, the American film and television industry released more than 700 movies and 400 scripted television shows. There are now over 130 lawful online sources for creative content in the United States and 470 sources globally.
The Encrypted Media Extensions (EME) specification published by W3C is a key building block for the secure and seamless delivery of this content to audiences around the world. EME advances a new generation of web-based content delivery with improved user functionality, security, and privacy. The MPAA appreciates the productive, collaborative work of the W3C and its many stakeholders on this important advancement to improve the consumer video experience.
Alex Deacon, Senior Vice President, Internet Technology
NBCUniversal (Comcast)
NBCUniversal is committed to bringing high-quality entertainment to viewers across the globe in a trusted, safe, and easy-to-use manner. We applaud the W3C's decision on EME, which will help provide reliable and safe access to the mechanisms used to access encrypted content, benefiting creators and users alike.
Michael Wise, CTO Universal Pictures
Netflix
Integration of DRM into web browsers delivers improved performance, battery life, reliability, security and privacy to users watching their favorite TV shows and movies on Netflix and other video services. We can finally say goodbye to third-party plugins, making for a safer and more reliable web.
We believe this technology has been greatly improved at the W3C, where the world's experts on web technologies, web security, privacy and accessibility could all shape the outcome in an open process.
Mark Watson, Director, Streaming Standards
Recording Industry Association of America (RIAA)
We congratulate W3C and its members for voting to publish EME as a W3C Recommendation. This is a victory for common sense - EME is already being deployed on the web and implemented by most browsers. It allows the web to function more seamlessly and efficiently while preserving the necessary safeguards. It will ensure the optimal video viewing experience. In short, the adoption of EME as a W3C Recommendation will give users more of a great thing, and will keep W3C at the forefront of innovation and web standards. We applaud Sir Tim Berners-Lee and thank him for his successful stewardship on this issue.
David Hughes, CTO, RIAA
ATSC
The Advanced Television Systems Committee (ATSC) congratulates W3C on the publication of the Encrypted Media Extensions (EME). ATSC is completing a suite of ATSC 3.0 standards to enable the next generation of over-the-air terrestrial broadcasting and hybrid broadcast and broadband services.ATSC 3.0 standards are based on Internet Protocol and other web-based standards, including MPEG DASH and W3C HTML5, as well as EME. Our A/360 Security and Content Protection and A/344 Interactive Content standards both incorporate EME. The security and content protection capabilities made possible by EME provide important new opportunities for Broadcasters to deliver new services to the public.
Mark Richer, President, Advanced Television Systems Committee, Inc.
IPTV Forum Japan
IPTV Forum Japan (IPTVFJ) sincerely congratulates that World Wide Web Consortium (W3C) has published Encrypted Media Extensions (EME) as a W3C Recommendation.
Since December 2014, IPTVFJ has been publicly offering the “IPTVFJ STD-0013: Hybridcast Operational Guideline Version 2” standard which includes the technical specification for Video on Demand (VOD) services with HTML5-capable TV sets. EME is one of the key features in this standard.
IPTVFJ STD-0013 specifies the delivery method for audio-visual content based on MPEG-DASH (Dynamic Adaptive Streaming over HTTP) in detail. The method specified in this standard can be used for live streaming as well as VOD.
Various features such as accessibility and privacy protection are provided by the Web framework. IPTVFJ recognizes (1) EME should be used to handle content securely in the framework if needed and (2) thus EME allows to expand applicability of IPTVFJ STD-0013 as much as possible. It is the reason IPTVFJ adopted EME APIs promptly as the open standard to be used in IPTVFJ STD-0013. Now IPTVFJ STD-0013 is being deployed to the actual Integrated Broadcast-Broadband (IBB) services in Japan.
Jun Murai, Chief Director, IPTV Forum Japan
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