Live Webcasting Solutions Buyer's Guide
很多正在浏览本期文章和广告的人已经从事在线视频业务很长时间了. Perhaps most of you got started in the last century. Drop yourself back into the '90s, 你可能还记得那个邮票大小的视频，里面有一个很酷的旋转风车, letting you know that something called buffering was taking place, but you still might get to see something eventually. 看了一辈子电视的观众来到网络世界，不知道缓冲是什么, and they didn't care, 因为他们中的大多数人都不想等视频，因为他们想上网冲浪.
Why should they wait for that video? 有更吸引人的内容和更高质量的观看体验. The pipes were too small, the encoding too complicated, 这个工具太难用了，而且没有太多的盈利方式来迫使任何人跨入在线视频领域. I'm not sure the "M" word even existed in the last century. 尝试在线直播视频活动的想法只是一群被误导的极客们的疯狂言论，他们手头上有太多的时间——我们欠他们的比我们想象的要多.
挪威有一家名为TV 2的电视台，通过宽带为观众提供6Mbps的直播流. The NFL and NBC put together Sunday Night Football Extra online, in HD, with five view-selectable camera choices, picture-in-picture, and full DVR control. 我在这篇文章中谈论的大部分内容最好简单地描述为“生活”.“所有的直播，所有的时间，和技术，使其成为一个引人注目的观看体验. 越来越多的公司提供软件和硬件生态系统来实现这一目标. Digital Rapids, Sonic Foundry, Inlet Technologies, Adobe, Microsoft, Go-Live, Telestream, Livestream, Ustream, 如果你是一个面向多个屏幕的大型新闻和娱乐网络，或者是一个正在播放本周主场比赛的小型大学或高中，无数其他公司都有强大的解决方案，可以让你在线直播. 因此，让我们来看看一些硬件和软件解决方案，它们将给你一个感觉，这些解决方案可能会让你的直播更容易一些.
I was talking with John Bishop, Inlet Technologies的联合创始人兼产品和业务开发高级副总裁, about the hardware-based side of live. 入口有一个愿景，视频可以看起来比邮票大小，并可以达到广播般的质量在宽带上. Many are familiar with Inlet's Spinnaker live streaming appliances. Its products have been adopted by large news and entertainment networks; it's also one of the technologies behind NBC's coverage of the last Olympic Winter Games, Major League Baseball, and live 3D online coverage of the 2010 Masters Golf Tournament. 有趣的是，Inlet的Spinnaker设备不使用任何专有硬件，因为, as Bishop explained, "Spinnaker is a ‘software-enabled' hardware appliance. 我们仍然看到宽带和移动视频领域的变化速度惊人, 我们希望有一种软件方法，使我们能够对不断变化的市场需求做出反应.“随着每个人都将多屏幕作为下一代iPhone手机，这些市场需求正在增长, Android device, or iPad comes to market.
Adaptive Live Streaming Solutions
The distinction between hardware and software solutions appears to be blurring; very often, 来自所谓传统软件公司的最先进的软件被整合到硬件设备中. Adobe HTTP动态流媒体和微软平滑流媒体都是硬件设备交付的组成部分，这一事实证明了这一点. 正是这些来自Adobe和微软的自适应比特率技术在过去几年中对流媒体产生了巨大的积极影响.
While a technical explanation of adaptive bitrate is available from many sources, Bishop noted, "Customers need to know that adaptive bitrate is not a sandbox technology. It is deployed at some of the largest data centers in the world. If customers are using a streaming solution circa 2005, they are so far behind the curve that they are almost using an inferior product."
Adobe使用Flash完成了一些大型的网络直播活动, including President Barack Obama's inauguration, Michael Jackson's funeral, and World Cup Soccer with ESPN. 为了保持增长，并确保互联网继续成为人们可以围绕流媒体建立商业模式的地方, Adobe invested in HTTP delivery. As Kevin Towes, senior product manager at Adobe, states, "With HTTP delivery, 客户可以利用它提供的好处，例如通过具有更大容量的CDN进行访问的能力，以及最终承诺的更低的交付成本."
自适应比特率技术也正在成为实时组播传输的关键组成部分. Succinctly, 而传统的流媒体是服务器和客户端播放器之间的一对一关系, multicast clients subscribe to the same multicast IP and receive the same stream. 这显然可以节省带宽，但在网络配置和基础设施费用方面总是存在障碍.
Towes补充说，其中一个关键挑战是在不影响电子邮件和语音等核心网络服务的情况下，在企业内部提供高质量的视频体验, 同时减少了提供这种体验所需的网络基础设施. Adobe通过将IP组播和应用级组播与Flash Player 10中引入的点对点功能和组播功能融合在一起来解决这个问题.1. 这有效地允许有能力使用多播的企业用户帮助那些不能使用多播流的用户体验相同的视图，同时实现带宽节省.
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