封闭和开放的互联世界：苹果vs.DLNA

仔细推敲“互操作性(interoperability)”这个消费性电子产业界的专业术语，我无力地发现那也许是一个最夸大且过度承诺的名词，而并非意味着最低程度地实现(under-delivered)。 市场研究机构IHS资深分析师Jordan Selburn 最近问我的一个问题加强了我以上的观点；他问的是，有见过不懂科技的人能轻松将一段视频发送到朋友的电视机上，完全不用进行设备或网络的配置设定吗？我不会回答“不曾见过”，但那确实是不容易看到的景象。 但从另一方面来说，这个指控对数字生活网络联盟(Digital Living Network Alliance，DLNA)不太公平。DLNA是一个成立于 2003年的技术标准组织，致力于为消费者在连网家庭中使用的各种设备推动互操作性；该组织成员有超过250家厂商，包括三星(Samsung)、索尼(Sony)、英特尔(Intel)以及多家中国业者，但苹果(Apple)不在其中。 如果你没听过DLNA，可能的原因有三：第一，你太年轻了，不知道十年前曾经发生的事；第二，DLNA虽然在产业界做了不少重要的事，但因为成员们都很低调，因此媒体界与消费者都没注意到该组织这十年来的成就；第三，我个人认为，苹果抢走了DLNA的风头。 与DLNA致力于让所有品牌产品都能互通的任务相反，苹果的目标就是在消费者面前展示它们家的AirPlay无线基地台，如何能透过Apple TV将它们家 iOS 平台装置上(包括iPod、iPhone、iPad等)的多媒体内容串流到高画质电视(HDTV)与喇叭播送出来。 Selburn表示，基本上苹果已经提供了一种互操作性的体验，或是让该品牌的使用者相信那就是互操作性；但是当然，苹果实际上是一个封闭的系统：“尽管DLNA的程序更为明确且令人印象深刻，苹果的方案看起来更像是能‘马上就生效’。” 对那些自DLNA自Sony发源以来就一直关注该组织的人来说，它是产业界一个大获成功的案例，但大部分都不为人知。顾问机构Envisioneering Group 研究总监Richard Doherty形容，DLNA是“产业界在无缝设备覆盖以及资源共享进展上最成功的案例之一”。 DLNA的概念非常简单，只有两种装置──其中一种是被观看或是聆听的DLNA客户端装置，另一种是传输内容的DLNA服务器。DLNA的目标是让不同品牌的所有装置能透过有线或无线的方式进行沟通，并无缝地分享内容。 Doherty指出，举例来说，若没有DLNA十年来努力奠基，Marvell就不可能在1月的国际消费性电子展(CES)期间，展示其“只要一个弹指就能无缝地将手机与平板上的高画质视频内容传送到电视机上”的解决方案。 不 过要说整个消费性电子产业界已经达到了互通的愿景还稍嫌太早，实际上还差得远；原因有数个。DLNA无法克服的关键挑战包括：不断升级的多媒体格式、编解码技术以及媒介；内容供货商订定的数字版权管理方案(Digital Rights Management)；以及各家消费性电子大品牌尝试着以DLNA为基础，打造在自有品牌装置之间、自家保证的互操作性。 此外，在未来几年，如果DLNA的触角──以及知名度──将扩展至物联网(IoT)领域，恐怕将面临更大的挑战。Doherty表示，到时候DLNA必须从有线/无线设备覆盖，往非实时性云端服务、安全性、授权等方面发展。 DLNA主席暨总裁Nidhish Parikh最近接受EETimes美国版编辑访问时坦承，跟上各种新规格的发展脚步是该组织“永远不会结束的任务”；而在DLNA持续关注新编解碼技术与新标准同时，该组织也在寻找新的转码(transcoding)架构。 转码将可简化并缩短DLNA客户端装置辨识与播放特定内容格式的时间，Parikh仅表示该组织正在进行相关计划，但详情他不愿多谈。 本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：拉拢服务供应商

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{pagination} 拉拢服务供应商 在此同时，DLNA到目前为止最大的进展，或许就是与服务供货商的合作；对此Parikh表示这是与DLNA所订定的视讯标准 Commercial Video Profile (CVP-2)有关，也是DLNA已经进行了好一段时间的最大发展。 Envisioneering Group的Doherty表示，DLNA订定CVP-2的工作“非常重要”，这将有助于DLNA覆盖范围的扩大与传递。基本上，借着新订定的CVP-2 准则，DLNA能解除服务供应商在付费电视内容于家庭网络中传播时的安全性疑虑。支持CVP-2规格的客户端设备预计可在今年稍后陆续问世。 根 据DLNA的说法，包括Comcast、Cox、Time Warner Cable等内容服务供应商，现在能安全地将付费电视内容包括现场直播节目、随选视频、DVR内容等，传递到订户的家庭网络终端设备上，例如电视、游戏机、蓝光播放器、平板设备、手机与PC等等；而无论在任何一种设备上，CVP-2能提供使用者一致性的观赏体验。 CVP-2 规格加入基本DLNA标准的强制性功能包括：HTML5远程用户接口，能支持PING等远程操作的装置状态诊断功能，唤醒省电模式CVP-2客户端装置 的功能，以MPEG-DASH标准接收ABR (Adaptive Bit Rate)内容的功能(允许高画质多媒体内容透过因特网串流，并适应家庭网络的带宽变动)。 此外CVP-2也支持采用DTCP-IP Link Protection技术的内容保护、以优先性为基础的QoS (quality of service)，支持所有的技巧模式(trick mode)等等。 随着消费性电子厂商之间的竞争日益激烈，要让DLNA的成员维持合作，并要求它们将“DLNA认证”标志摆在他们自家品牌互操作性之前，是很不容易的事。例如三星，该公司告诉消费者能如何容易地在同一个网络里，将Galaxy Tab平板与三星电视机无线链接。 此 外索尼与松下(Panasonic)也以类似的方式推销各自的产品互操作性，虽然大多数都是藉由DLNA标准所达成。不过这种现象Doherty并不担心， 根据他的观察，这些“垂直”的互通世界，正缓慢屈服于利用支持DLNA之设备与服务共享的优势，毕竟：“很少有人会采购来自单一制造商的多种产品。” 有 部分供货商则是采取更务实的做法，也就是让产品同时支持AirPlay 与DLNA的功能；产业界并非分成“苹果”，以及“非苹果”两派，人们越来越了解到，这两个阵营必须共存。藉由结合两种技术，DLNA实际上能让人们将苹果设备上的内容，不一定要藉由iTunes就能在其他设备上播放。 DLNA正将自己定位成沟通封闭的苹果生态系统，以及范围显然更广大、也更开放的DLNA生态系统之间的桥梁；也许将世界分为“苹果iOS vs. DLNA”的观念已经过时了，DLNA正默默地一步步往前迈进。 本文授权编译自EE Times，版权所有，谢绝转载 编译：Judith Cheng 参考英文原文：Did Apple Steal DLNA's Thunder?，by Junko Yoshida

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{pagination} Did Apple Steal DLNA's Thunder? Bridge iOS devices and non-Apple products Junko Yoshida, Chief International Correspondent TOKYO — As I ponder, weak and weary, the jargon of the consumer electronics industry, the term “interoperability” leaps out as perhaps the most overblown and over-promised term, not to mention under-delivered. Jordan Selburn, senior principal analyst at IHS consumer electronics, recently asked me a question that reinforces my point. When’s the last time, he asked, anyone actually witnessed “a completely non-tech savvy person walking into a room and sending a video to a friend’s TV without configuring a device or the network?” I wouldn’t say “never.” But it’s a phenomenon that’s hard to come by. On the other hand, this is a sweeping indictment that isn’t exactly fair to the Digital Living Network Alliance (DLNA). DLNA is a technology standards organization, founded in 2003, to build industry consensus to advance the interoperability of products in consumers’ connected homes. DLNA members include more than 250 companies – Samsung, Sony, Intel, Microsoft and a number of Chinese vendors – but not Apple. If you’ve never heard of DLNA, there are three likely reasons. One, you’re too young to remember anything that happened more than a decade ago. Two, DLNA has done a lot of heavy lifting within the industry, but so quietly that vendors, the press and consumers haven’t noticed the remarkable efforts of the 10- year-old organization. Three, in my opinion, Apple has stolen DLNA’s thunder. In contrast to DLNA, whose mission is to make every product of every brand discoverable and interoperable, all Apple has to do is show consumers how its (proprietary) AirPlay wirelessly streams the content on a (proprietary) iOS device (iPod, iPhone, iPad, etc.) to HDTV and speakers via (proprietary) Apple TV. In essence, Apple has delivered “such an [interoperable] experience, or at least the belief in such, in their user base,” said Selburn. Of course, what Apple delivers is a closed system. “But it seems closer to the ‘it just happens, and it just works’ paradigm despite DLNA’s clear and impressive progress,” said Selburn. DLNA: untold story For those who’ve followed DLNA since its inception at Sony, DLNA is a big industry success story, but largely untold and uncelebrated. Richard Doherty, research director at the Envisioneering Group, described DLNA as “one of the industry’s finest success stories as far as seamless device discovery and resource sharing goes.” The concept of DLNA is pretty straightforward. There are two types of DLNA devices – a DLNA client where the content is viewed or listened to, and a DLNA server that sends the content. DLNA’s goal is for all devices of different brands to communicate wired or wirelessly, and share content seamlessly. Without DLNA’s decade of spadework, it wouldn’t have been possible for Marvell, for example, to show at the International CES last month, “seamless ‘flicking’ of HD video content from mobile phone and tablet to TVs,” said Doherty. It’s premature, however, to assume that the C.E. industry has already reached its interoperability nirvana. That’s still pretty far away -- for several reasons. Key challenges DLNA has been wrestling with include: constantly improving formats, codecs and containers for media; Digital Rights Management imposed by content owners; and big CE brands trying to create their own “guarantee” of interoperability among their own branded devices built on DLNA variations. Further, in coming years, if the industry is to extend DLNA's reach -- and brand awareness -- to the Internet of Things, an even bigger challenge will rear up. Doherty said DLNA would have to extend “what started as a wired and wireless DLNA discovery to non-real time cloud services, security and authentication.” In a recent phone interview with EE Times, Nidhish Parikh, chairman and president of DLNA, acknowledged that keeping up with the new formats is “a never-ending task,” for his organization. While DLNA continues to address new codecs and new formats, the group is also looking at a new “transcoding” scheme. Transcoding would ease and “shorten” the time for a DLNA client to recognize and play back a particular format. Calling the transcoding project “a work in progress,” Parikh declined to elaborate. Bringing in service providers Meanwhile, DLNA’s biggest progress thus far might be its work with service providers. DLNA’s chairman and president Parikh is hanging his hat on the DLNA-developed Commercial Video Profile (CVP-2). He called it “one of the biggest developments [DLNA has pulled off] for a while.” Calling DLNA’s efforts on CVP-2 “very important,” Doherty said it would “enrich DLNA discovery and delivery.” In essence, with the new CVP-2 guidelines, DLNA has solved service providers’ concerns over secure distribution of Pay-TV content within a home network. The CVP-2 profile-based clients are scheduled for release later this year. Companies such as Comcast, Cox, Time Warner Cable, and others can now “securely distribute Pay-TV content -- which includes live content, video on demand, DVR content -- to their subscribers’ retail home network devices,” according to DLNA. Those retail home network devices include televisions, game consoles, Blu-Ray players, tablets, phones, and PCs. CVP-2 enables “a consistent service provider user navigating and viewing experience regardless of device,” the consortium added. Mandatory features of the CVP-2 profile client, added to the basic DLNA guidelines are: HTML5 remote user interface; capability to diagnose the status of the device allowing remote operations such as ping, trace route; capability to wake up the CVP-2 client if in idle power mode; capability to receive Adaptive Bit Rate content using MPEG -DASH standard (MPEG-DASH stands for MPEG-Dynamic Adaptive Streaming over HTTP. It allows for high-quality media to be streamed over the Internet, and adapt to changing bandwidth of the home network); protection of content using DTCP-IP Link Protection; priority-based quality of service; all trick modes; and others. Vertical worlds of interoperability At a time when CE giants are competing fiercely among themselves, it’s not easy to keep DLNA members in line and ask them to put the “DLNA-certified” logo before their own interoperability brand. Take the example of “Samsung All Share Play.” Samsung tells customers how easy it is for a Samsung Galaxy Tab tablet to connect wirelessly to a Samsung TV on the same network. The Korean giant’s concept follows Apple’s model, just as Apple pitched AirPlay as something that requires little effort to play content from an iPad to another up-to-date Apple product. Sony and Panasonic have similarly promoted their own world of interoperability, even though much of their work leverages DLNA guidelines. Doherty, however, isn’t worried. He observed that those “vertical worlds of interoperability have slowly yielded to take advantage of DLNA operable equipment and services sharing.” The fact is, as Doherty pointed out, “Very few people own a variety of products from a single manufacturer.” Some vendors are already taking a much more realistic approach by incorporating both AirPlay and DLNA functionality into their products. Rather than pitting Apple’s iOS products against a host of non-Apple devices, there is a growing recognition that both need to coexist. By incorporating both technologies, DLNA is practically enabling people who have Apple content to connect with and play that content on other devices, by using players and services other than iTunes. DLNA is positioning itself to bridge the gap between the closed Apple ecosystem and the significantly broader and more open DLNA ecosystem. Maybe, dividing the world in two – Apple’s iOS universe vs. DLNA – is becoming an outdated concept. In is quiet style, DLNA might have already moved on.