Beyond Standards: Moving Past MPEG to Create a Video-Friendly Web

编解码器, 缓存, 传输是视频压缩和传输所需的三个主要组成部分.

每个人都有一个独特的角色. 编解码器 are at the core of compression and decompression. 它们被用来缩小视频点播(VOD)文件的大小，或者降低在保持视觉质量的同时在网络上传输直播流所需的带宽. The last two building blocks—transport and 缓存, 将永久或半永久内容存储在离最终用户更近的地方，这一行为历来被认为是流媒体行业的专业知识之外的，更符合路由和互联网架构.

但这种情况正在改变, thanks in no small part to the “Netflix-ification” of the web, 因为OTT内容越来越受欢迎，给流媒体行业几十年来所依赖的基础设施和交付方式带来了压力.

Alongside this need to rebuild the web to be more video-centric comes a parallel desire, 至少对一些人来说——不管他们现在是否需要一个可行的解决方案，或者认为他们可以利用这种需求——逃离基于标准的视频的限制.

From streaming media’s early days—when codecs such as MPEG-1 faced off with Intel’s Indeo, 微软的Windows Media, 和RealNetworks的RealVideo——在标准和进步之间一直存在一场潜在的拉锯战, 在开源和许可之间, between one-size-fits-all and customization on a per-use basis.

The flag in the middle of the tug-of-war rope, dangling precariously over the mud pit that awaits the losers, 是创新. 如果标准组织赢了, with their decision-by-committee mentality that slows or even stops the pace of innovation, 然后，该行业将面临低效技术无法跟上视频消费增长步伐的时期.

本文将探讨围绕这一拔河场景的一些紧张局势，以及一些有望从放弃标准中获益的参与者.

罪魁祸首:视频点播

视频点播内容消费, 到目前为止，绝大多数在线媒体都是通过在线视频平台(ovp)和OTT服务提供商提供的, 增长速度如此之快，以至于迫切需要新技术来跟上这种增长.

For VOD content, the codec and its encapsulating encoder make up a key battleground. Encoders are used to compress files either faster or slower than real time, 取决于最终编码视频所需的质量和节省带宽的需要.

基于标准的视频压缩通常来自两个组织:国际电信联盟(ITU)和电影专家组(MPEG)。.

国际电联是一个有150年历史的组织，总部设在日内瓦，成立于1865年，是电报标准的仲裁者. 作为联合国的一部分, 国际电联的任务是确保电信——从无线电频谱到电话交换机再到最新的互联网标准——在全球范围内相互操作. The ITU has a Video Coding Experts Group (VCEG) that ratified the ITU-T H.264标准 for use in telecommunications, namely in videoconferencing.

MPEG出现还不到150年, 但由于现在电影都是用数字格式拍摄和传送的，所以它的影响是巨大的. These movies are considered premium content, due to Netflix’s and other OTT providers’ desire to charge subscriptions for premium content.

MPEG取H.264标准, reworked it slightly to emphasize its use for high-quality VOD content, 并将其命名为MPEG-4 Part 10. 在某一时刻, 国际电联和MPEG共同成立了一个联合工作组(现在称为视频编码联合协作小组(JCT-VC))，并推动了高级视频编码(AVC)名称作为联合标准的一部分. That’s why we often see terminology such as AVC/H.264 when referring to the same compression-decompression technology.

坚持视频标准(如AVC)的编码器公司之间的区别在于编码解决方案的质量, 因为解码器本身至少在理论上是在通用范围内以相同的方式实现的. Encoders can encode in either constant bitrate (CBR) or variable bitrate (VBR). 一般认为，CBR内容可以更快地编码(通常是单次编码)，而VBR需要在内容上进行多次编码以产生更高质量的视频文件.

Some innovations, 虽然, turn that on its head. 例如, EuclidIQ最初采用了一种忽略基于标准编码的感知质量优化方法——以及Richard Wingard提出的“宏块训练轮”, 公司的联合创始人兼首席执行官, 喜欢解散——在保持视觉质量的同时获得显著的带宽减少. (Full disclosure: I worked for EuclidIQ from October 2015 until May 2016.)

The problem with this approach is that customers must download a special decoder. This problem faced older innovators such as On2 (with its VP7/8 codec, 后来卖给了谷歌), and it still affects current industry innovators such as V-Nova (with its PERSEUS codec). 正如Jan Ozer在他的 V-Nova方法的概述，需要有一个专门的解码器意味着用例仅限于封闭的环境. 机顶盒也是如此, appliances with the specialized decoder flashed to silicon, 甚至是终端用户，他们被迫下载解码器来观看经过创新编解码器增强的单个视频.

EuclidIQ 在EuclidVision遇到了这个问题. It ultimately moved back toward the macroblock and H.提供符合标准的IQ264感知质量优化，作为领先的开源H . 264的插件.264编码器.

Licensing: One Company, Two Patent Pools, or None at All?

除了技术问题, 虽然, a bigger issue seems to arise every time the committees innovate: licensing.

流媒体 已经覆盖了错综复杂的牌照问题多年来，以H开头.264授权池由MPEG-LA启动，作为AVC专利池持有人创新的一种赚钱方式.

当行业受到编码器许可不确定性的影响时，创新似乎蓬勃发展, 转换器已经, 以及关键的交付工具. 也许“繁荣”这个词太有希望了, 但在这些时期，创新似乎作为一种独特的卖点被提上了前台.

As an example, let’s ignore On2 Technologies’ history during the early H.264 licensing snafu days and consider the more recent uncertainty around the HEVC/H.265编解码器. 围绕这一MPEG-ITU联合标准的许可问题甚至迫使大公司采取铤而走险或投机的做法, if you’re so inclined—steps to fill the void.

来自思科公司乔纳森·罗森伯格的一篇博文, championing the idea of a royalty-free codec, 很好地总结了这个问题. 2015年的帖子， “World, Meet Thor—a Project to Hammer Out a Royalty 免费的 Video Codec,” first notes that Cisco has worked to make H.264 the foundation of its real-time communications tools, such as WebEx.

Rosenberg then states the case for patent licensing uncertainty for H.264’s successor, known interchangeably as H.265和HEVC. “The next generation codecs are just beginning to emerge,他写道。. “There are two of note—Google’s proprietary VP9 codec, and the industry standard H.265 (HEVC) codec, which is the successor to H.264 (AVC).”

H.264有一个许可池, 罗森博格指出, but the HEVC licensing scenario involves two competing license pools. “Two distinct patent licensing pools have formed so far, and many license holders are not represented in either,他写道。. “H.265 from these two pools is up to sixteen times more expensive than H.264元/件. H.264 had an upper bound on yearly licensing costs, whereas H.265没有这样的上限.”

The end result, according to Rosenberg, is a limitation on using “H.265在任何一种开源或免费分发的软件应用程序，如web浏览器. 他们还禁止在免费增值产品中使用它，比如WebEx或Cisco spark，这些产品都有用户可以免费使用的版本.他解释说:“H.265] is not something that can serve as a universal video codec across hardware and software. 因此, we believe the industry needs a high quality, next-generation codec that can be used everywhere.”

换句话说, if you don’t like the terms of a committee of large companies, you can use a codec created by another large company in its place.

根据Rosenberg的说法, Cisco contributed Thor “as an input to the Internet Engineering Task Force (IETF), 2015年末，哪家公司开始了开发下一代免版税视频编解码器的标准活动. He also notes that Mozilla is working to create a similar royalty-free codec called Daala.

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