2014年9月15日
By 1月时特约编辑
专题文章

HEVC:我们到了吗?

HEVC /小时.265在2013年1月突然出现, when it was released for production by the two standards bodies that helped create it, the International Telecommunication Union (ITU) and Moving Picture Experts Group (MPEG). 现在，在它发布大约18个月后，HEVC的可用性如何? 嗯，实际上，不是很好. This article will look at HEVC’s status in three segments: delivery to computers and notebooks, 移动, 和OTT, 确定影响每个市场的趋势和价值主张.

概述

让我们从一个简短的概述开始. HEVC /小时.265是AVC/H的后继编解码器.它的设计提供了两个关键的好处:与H . 264相同的质量.264大约50%的数据速率，4K和最终8K视频. 关于HEVC实际质量的报告各不相同. 2014年5月, 戴夫Ronca, Netflix编码技术经理, HEVC产生的质量和x264差不多, 当我拿起 10倍的时间来编码. Most encoding vendors report that HEVC delivers between 30%-50% file size savings at the same quality as H.264个我的大部分测试都证实了这个范围.

像H.HEVC是一项专利技术. A group sponsored by MPEG LA includes most intellectual property (IP) stakeholders, 尽管一些知识产权所有者尚未加入该组织. MPEG LA released a summary of expected license terms in January 2014, which included a $0.100后的编码器/解码器产品每单位特许权使用费为20,000个单位, 最初的年薪上限是2500万美元, 尽管最终条款尚未确定.

HEVC交付到台式机和笔记本电脑

我们到了吗?? 不，差远了. 但是VP9是.

尽管移动和OTT交付占据了大多数头条新闻, most streaming producers send the bulk of their streams to computers and notebooks. Most computers and notebooks have the CPU horsepower to play at least 720p HEVC streams. Many can play 1080p and battery life is not as great a concern as it is in mobile markets. 来自多个供应商的编码工具已经准备就绪. 所有这些都是事实, you would think that the potential bandwidth savings of between 30% and 50% would accelerate HEVC usage by high volume producers, 但事实并非如此, 原因如下.

首先，不像H.264，没有广泛可用的免费播放器HEVC. Adobe has announced that it will support HEVC in its Flash-based premium distribution platform, 黄金时段, 没有具体的可用日期, 但还没有宣布在免费的Flash Player中支持HEVC. 根据DivX LLC的数据，超过4个.700万用户下载了HEVC插件为他们的免费DivX播放器, which isn’t sufficient for an ESPN or CNN to start streaming HEVC solely to these players. VideoLAN的VLC媒体播放器包括HEVC播放, but again doesn’t have the penetration necessary for general-purpose streaming.

考虑到潜在的带宽节省, I wondered if any large content producers were seeking to directly license HEVC playback from IP vendors like Ittiam and Fluendo, 谁通常将编解码器技术和相关播放器授权给移动设备, 机顶盒, 以及类似的设备制造商. 两家公司都报道了一些初步的讨论，但没有任何进展.

These conversations raised the question about how a third-party HEVC decoder might fit into a web publisher’s decoding workflow, which is primarily Flash-based at this point for high-volume producers of premium, drm保护的内容. I spoke to several technologists who deemed it unlikely that a streaming producer could shoehorn third-party HEVC playback into their existing Flash-based players. 而不是, they’d likely have to create a separate application that viewers would first have to download, 大多数制作人不喜欢哪一点. 出于这个原因, it seemed that most premium producers seeking to leverage HEVC in the short term would explore the relatively painless, 虽然可能更贵, 黄金时段的道路，而不是自力更生.

那些没有DRM的内容呢? 这就是事情变得有趣的地方. 我们正处于通用流媒体的一个巨大转折点, 由于现在无处不在的媒体源扩展(MSE)支持, HTML5 playback has become sufficiently robust for most producers of non-DRM content to stop using Flash. 具体来说，MSE提供了自适应流媒体和直播，两者都使用H.264和VP9, 它是HEVC的竞争对手，可以在谷歌浏览器中免费使用, Mozilla 火狐, 和Opera浏览器.

YouTube已经部署了VP9，并声称它提供了H.264 quality at half the data rate and has cut rebuffer rates by 25% in developed markets, and 100%投资新兴市场. One video technologist at another large publisher of non-DRM protected content, 谁要求不具名, 他的公司也在考虑VP9.

YouTube claims that VP9 delivers the same quality at up to 50% compression gains.

因为VP9在支持它的浏览器中是HTML5兼容的, 它完全符合新的MSE框架. 显而易见的问题是缺乏对Internet Explorer和Safari的支持, 哪些YouTube通过提供H.264到这些浏览器，与Flash回退到传统浏览器. 尽管如此, 如果我正在过渡到媒体源扩展, 而且我的带宽成本很高, 我会认真考虑添加一组自适应VP9编码, 虽然不是每个人都同意.

例如, an employee of one distributor of non-DRM movies (who also requested anonymity) says the company is currently evaluating HEVC, but didn’t expect to deploy to consumers until hardware decoders hit a critical mass. 尽管该公司正在积极探索向HTML5的过渡, 它希望在2015年实现哪些目标, 它没有评估VP9，也没有打算部署它.

A TV broadcaster with a huge web presence felt that “HEVC is inevitable -- not just for UltraHD, 但在整个分辨率和质量水平的范围内,另一位匿名人士说. “But I don’t think there will be a ton of movement until hardware decoders are ubiquitous in the consumer devices. We’re keeping our eye on it, but don’t anticipate doing much with it quite yet.“至于VP9? “一般来说，VP9(和VP8)不在我们的雷达上, 我不希望我们卷入其中.”

对主要服务提供商的看法如何? I checked with Casey Wilms, product manager of the media backbone group at Brightcove. Wilms reported that while Brightcove has received frequent inquiries about HEVC, 很少有客户询问VP9. 也就是说, Brightcove is very bullish on the Media Source Extensions and Wilms predicts that “we’ll be shocked at how fast” it takes off. Wilms预计HEVC将在广播市场占据主导地位, 它还不能用于HTML5, Brightcove将提供客户需要的任何编解码器.

我通过电子邮件与创作产品管理总监迈克尔·戴尔进行了交谈. 他说，卡尔图拉也看好MSE, though 创作 foresees “Flash being around as long as IE 10 or less is being used.而创作也认为VP9的需求有限, Dale承认:“VP9的升级路径比HEVC更清晰, as it has a much smaller ecosystem and is less bounded against particular pieces of hardware.” Dale feels that VP9’s success will depend upon how effectively Google can leverage its part in the video ecosystem to promote the codec.

最后, 蒂姆·拿破仑, 数字广播解决方案提供商All digital的首席策略师, 对VP9的需求很少. 对H.265 is in high-resolution screens in the connected TV market,” Napoleon says. “Bandwidth savings for low resolutions for mobile application is not being widely asked for yet. H.264仍然被广泛支持并且运行良好.”

显然，VP9是免版税的，但它并不是完全免费的. 这将会有很大的编码成本, 添加自适应组会增加存储和管理成本, 并降低了整体内容的可缓存性, 可能增加运输成本. 也有挥之不去的诺基亚的专利侵权指控. 仍然, the math is pretty simple; if you’re moving to MSE and you could save significant dollars by cutting bandwidth on video delivered to Chrome, 火狐, 和歌剧, VP9值得一看. 如果你坚持使用Flash，那就不是. 展望未来, 如果微软和苹果为IE和Safari授权HEVC, 这是人们普遍预期的, 你有更多的数学要做, though it’s much more likely that your HEVC encodes will be able to perform double or triple duty for mobile and OTT.

下一个页面