Video: How to Assess and Compare the Value of Next-Gen Codecs

了解更多关于新兴编解码器的信息流媒体的下一个事件.

观看这个小组的完整视频， DT102A: Managing Transition to HEVC/VP9/AV1 with Multi-Codec Streaming, in the 流媒体 Conference Video Portal.

Read the complete transcript of this clip:

保罗MacDougall: Going through the real reasons why we're looking at this codec value--当然, 支持HDR 4K, 带宽效率. I really love that users have that higher-quality experience over the same connection that they can have.

Then, 当然, for many operators, the reduced storage costs. You get around that by having the smaller files on your origin storage on your CDN, you're going to have less bits to keep around. 和, 当然, 如果你进入那些更大的编解码器, 或者像4K这样的大帧, 具有更大的位深, those are going to have substantially larger files, so you really do need to have that kind of efficient codec to deliver t在这里.

We can take a look at what some of that efficiency looks like in the real world. Some of the research that we've done around this, we can start out with H.264 t在这里 in the middle of the image, on the left side, t在这里. We can see about an 8 Mbps 1080p as our reference point. 我们可以将其与VP9进行比较. The 1080p will get similar visual quality at about 5.6 Mbps, and HEVC is somewhat more efficient than that, getting a similar visual quality at about 4 Mbps, so about half that bandwidth span that you get over H.264. 当然, that also lets you reach your mobile users, 使用低速连接的用户, with that higher-quality end-user experience.

在右边, 在这里, this is a chart that really shows you what the efficiencies are like on a broader range of bitrates, 以及更大范围的PSNR值. For those not familiar, PSNR is Perceived Signal-to-Noise Ratio. It's an attempt at a quantitative metric for determining what that visual quality is. T在这里's a great deal of debate in the industry. 事实上, t在这里's a whole bunch of people out on the show floor over t在这里 that could get into all kinds of very religious arguments about what metrics are most appropriate t在这里. But conversationally, PSNR is a really good metric to just kind of talk about what we see 在这里.

To help you guys understand this a little bit, 看看这张图表的底部, this is the bit rate in kilobits for a video asset. 和 then, this is the perceived quality over 在这里. 和 what we can do is, we can take a look at H.264年在这里, 就是这条低曲线, 然后我们有编解码器, 例如, 灰线中的HEVC, 橙色的VP9, AV1用蓝色表示. The goal, with any of these codecs, is to try and make this curve as far as possible to the left. That means that you're going to be getting values that are the highest visual perceived quality, 在那里花最少的钱.

What we see 在这里 is t在这里's quite a separation of these next-generation codecs from H.264个指标. 和 when we get up into these higher bitrates, 甚至还有更戏剧性的分离, 这对4K来说是至关重要的, 用于那些HDR工作流, that are really going to be letting you reach those audiences on those, 你知道, 新奇的4K电视等等, that they want to see all that best content in.