An Olympic Feat
将内容从一个位置转移到另一个位置需要一些计划, especially if it only happens once every four years.
这一点成为我在流媒体欧洲主持的一个小组讨论的关键话题, “直播和高清视频:网络视频能否扩大totv规模的观众??"
"Major CDNs find it a challenge just to stream 200Gbps, which breaks down to 100,000 people watching a 2Mbps signal," said Octoshape's Stephen Alstrup, 添加, “我确实相信媒体行业已经准备好了，当他们相信科技行业已经准备好了, 但我知道媒体行业仍然担心激进的流媒体战略."
在讨论期间，阿尔斯特鲁普提出了这一主张，讨论的焦点是今年最大的直播活动——美国互联网大会.S. 总统就职典礼——由几家服务提供商以标准清晰度直播, with the official stream being generated by iStreamPlanet.
The general consensus from Alstrup and his fellow panelists, Suzanne Johnson from Akamai and Josh Gagliardi from Highwinds, 有足够的准备时间和计划的现场活动是否能够扩大到合理的数百万观众. 据估计，总统就职典礼将同时播放900万至1200万部标准清晰度流媒体，并花了大约四个月的时间进行前期规划.
如果在台式机上用高清(720p或1080p)做同样的事情呢? 会议期间也讨论了这个问题，可在此找到点播版 在这里.
但随着上周温哥华即将举行的第21届冬季奥运会的直播阵容公布，这个问题变得更加尖锐. The planning cycle for the Olympics, which will be held in Vancouver, BC, from February 12-28, 和总统就职典礼的时间差不多吗, 但赌注更高，因为整个活动将以720p高清流式传输到桌面.
As announced by Perkins Miller, senior vice president, digital media, NBC Olympics, and Scott Guthrie, corporate vice president of the .NET Developer Platform at Microsoft Corporation, 温哥华奥运流媒体的花名册汇集了一组不同的团队成员, led by iStreamPlanet and Akamai.
Akamai has been gearing up toward this type of delivery, launching the Akamai HD Network in September.
"We're at television numbers," said Paul Sagan, Akamai's CEO, during the September rollout, “就像我们看到的一个事件——总统就职典礼——它的流量达到了1000万. Many have said that the internet's not capable of HD delivery. We disagree, 我们正在推出一种解决方案，它能够超越迄今为止所做的任何高清交付."
iStreamPlanet, for its part, 是否需要编码和传输大量的流来驱动消费者对各种内容的需求, all available at the same time.
一份新闻稿指出:“iStreamPlanet将对23个视频源进行编码. "All 23 feeds are originating from Vancouver, 并通过OC12通过IP多播传输到iStreamPlanet的拉斯维加斯网络广播运营中心."
The 23 feeds, including venue and broadcast feeds, an Olympic 新闻 Channel and one full-time Press Conference stream, 将遵循一个特定的过程流到观众的桌面.
NBC will multicast an H.264 1080p信号，从温哥华到NBC的纽约设施. 然后，多播将通过iStreamPlanet的私有OC12继续发送到拉斯维加斯, 它将被解码为HD-SDI，然后重新编码为720p Silverlight流实时, 通过与Inlet Technologies共同开发的硬件/软件解决方案.
“Inlet很自豪能够帮助NBC提供最高质量的温哥华冬奥会直播," said John Bishop, Inlet's senior vice president of strategy and business development. "Combined with IIS Live Smooth Streaming, 我们的720p流编码将帮助NBC提高观众留存率和球迷在线享受冬奥会报道的时间."
Another team member, 眩晕, 宣布已被选中为奥运会提供高清直播和点播视频播放器. 虽然该公司发布了一份标题为“有史以来第一次”的新闻稿(“眩晕为NBC环球报道冬奥会提供有史以来第一个高清微软Silverlight在线视频播放器”)，但它后来澄清说，“有史以来第一次”只适用于奥运会, as other HD Silverlight players already exist.
“使用Silverlight 720p高清视频播放器是奥运会的‘首次’体验," a company spokesperson said. “NBC环球正在使用眩晕开发的自定义播放器来提供这种播放体验."
When asked whether some viewers with very high bandwidth, such as U-verse or FiOS, 也许可以在1080p(甚至1080i)中查看一些展示内容, 眩晕列出了720p Silverlight传输的一个限制，这使得带宽要求高到足以阻碍1080p的观看.
该公司发言人表示:“奥运内容被编码为720p。. “如果你电脑上的网络带宽和视频渲染能力很高, 在全屏模式下，您将体验到样本内容的720p高清视频播放."
What exactly does 眩晕 mean by high bandwidth?
"If your actual bandwidth is below 5Mbps, or your playback device is video-challenged, then you will experience the adaptive nature of Smooth Streaming," the spokesperson said.
与其他行业专家的讨论表明，5Mbps可能比行业平均水平高出2-3Mbps, 因此，目前还不确定限制是否在Silverlight HD交付中, or merely an arbitrary number chosen by 眩晕, who controls the heuristics of the player.
Closer to the Olympics, I'll update readers on the status of preparations, 如果有额外的成员出现，也会更新球队名单.
[编者注:本文自最初发布之日起已更新. 原文引用的新闻稿错误地指出，iStream Planet将通过卫星接收内容, and also that Inlet would be doing encoding in Vancouver.]
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