Encoding at Scale for Live Video Streaming
My name is 雷Adensamer. 我是加拿大新成立的公司NETINT Technologies的营销总监, 我们正在引入一种基于ASIC(专用集成电路)的云编码和转码架构，它在大规模交付编码方面表现出色.
你可能很熟悉这个行业的一些挑战和趋势. We'll review some of those trends. 我们要做的第二件事是快速回顾一些用于在网络上进行编码和转码的替代架构, 然后我们将花一点时间讨论我们的解决方案在应对这些挑战方面的好处.
Video Streaming Delivery Architecture
Let’s start with the diagram shown in 图1 (below), a high-level video streaming delivery architecture diagram. 很明显, the objective is to take your video content, 无论是体育运动, 名人, 或新闻, and get that to as 许多 devices as you can. 现在, 这个源通常会以非常高的分辨率被捕获, 1080p或4K, so it's going to look beautiful on your TVs, but when it gets down to mobile devices, they have smaller screen resolutions. 它们的带宽更少，所以你不会将4K视频流发送到智能手机设备. It's a waste of money for your CDN spending, 但也, it's probably going to look bad, so somewhere in this workflow, 你需要大规模地进行编码和转码.
图1. Video Streaming Delivery Architecture
这需要你的输入，通常用H来表示.264编解码器, which gives you about 50x compression, 然后把它分解成比特率阶梯. At the workshop yesterday, 关于如何设计这些梯子和类似的东西，我们进行了一些很好的讨论. 然后这个阶梯被转发到内容分发网络中. That's where your ABR packaging is applied, maybe some of your DRM, and then it gets distributed to your display devices.
降低CDN成本
您需要很好地进行编码和转码，原因有两个:最大限度地提高最终用户的体验质量, 但更重要的是, you want to lower the bitrate cost for your CDN distribution, so let's talk about CDN cost.
In 图2(下面) we have a 1080p video that is being streamed for one month, and we're using the cost from Amazon CloudFront CDN, and so if you were to encode that using H.264, you could get a decent quality stream for about 8 Mbps. 如果你想连续一个月向一个人提供8mbps的流量, that's going to cost you $51, but if you were to encode that same stream using H.265，这是一种高效的视频编码算法，可以减少大约50%的带宽.
图2. Lower Bitrates Reduce CDN Costs
通过降低到4兆，你可以减少一半的成本. Once you've done your encoding, 这取决于将来有多少观众会观看该编码, hundreds of thousands or millions. You can see that it's a significant amount of money, 使用压缩编解码器分发这些视频可以节省大量费用, 这就是为什么像Netflix这样的服务在编码上花了这么多钱. 这就是他们如何在CDN分发成本上节省这么多钱的原因.
编码和转码容量增长和成本的驱动因素
让我们来探讨一下编码和转码的驱动因素, so we'll start 正确的 at the top in 图3(下面). According to the Cisco Visual Networking Index, 2016年至2021年间，消费者直播视频将增长15倍, 所以我今天在这里要告诉你们的是，如果视频通过网络的容量以pb为单位增长了15倍, the need for encoding capacity is going to be even higher, and it's going to be higher for three reasons.
图3. Drivers for Encoding and Transcoding Capacity Growth
One is you're going to be using more compression codecs. H.我们之前介绍的265为您节省了比特率成本, 但成本方面是，在你的网络中进行编码需要10倍的处理能力. That's one of the reasons that encoding is going up. The second reason is high-resolution videos. 现在大多数视频都是1080p，有时是720. There's a lot of early adoption of 4K. It's going to grow to 8K. It's going to grow to virtual reality, 因此，更高分辨率的视频在网络中也需要更强的编码处理能力.
其中一个关键趋势是用户生成内容，如图右侧所示 图4(下面). 在早期, 是关于体育的, 名人, and video on-demand world, 还有电影, 你可能会有数百个标题然后被编码, 但这样一来，你就有了将内容流式传输给数万或数十万人的好处. 与此相关的CDN节省使人们能够真正关注编码. "Yes, it’s a necessary evil. 是的，你能做到." But the cost savings were significant.
图4. Drivers for Reducing Encoding Costs
现在的趋势是，我们越来越关注用户生成的内容, which means more unique streams. Facebook Live is a perfect example of this. 许多, 许多, 许多 unique streams going through the network, that you need to share with your followers, but the number of followers is going to go down. 这是行业发展的趋势，从很少的编码到很多发行版本，到更多的原创内容片段到更少的东西.
Let's explore that relationship a little bit more. If I look at that line in 图4, 我也可以将这一行表示为编码节省的CDN, 所以, 体育, 名人, 电影. 你可以节省大量的CDN费用，这远远高于你的编码成本. 编码成本稍微高一些因为人们想要花钱获得高质量的编码, 但是随着它的下降, there's going to be a crossover point where if you have very, very few followers or viewers of that content, you're going to be losing money. 有必要降低编码和网络的成本.
The first benefit is obviously obvious. If you can lower your encoding cost, you're going to improve your margins, 正确的, 提高你的直播业务的盈利能力, 但第二个好处可能不太明显你把交点向右移动了, 所以这意味着你的编码基础设施可以用更少的观众来支持更多的直播.
With this trend to user-generated content, 该行业需要提供更多的审查，以了解您将如何进行大规模编码, 你将如何在经济上做到这一点，你将如何增加这种能力，特别是当我们进入这些用户生成内容的趋势时.
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