Video: How Can We Deliver 360 VR Streaming Beyond 4K?

了解更多关于4K VR 360 流媒体东部.

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德文郡科普利: 在视频制作流水线, 广播管道, 流式管道, 设备上的渲染管道, 电池寿命, CPU处理能力, GPU的权力, all those things have been scaled for standard HD video, 现在在某种程度上是4K视频. That's allowed us to get to 4K spherical--that is, 4K all the way around, or 360. 但要克服这一点是一个巨大的挑战, because at every point in that production chain you need to upgrade to something that puts you in uncharted territory. 显然有8K电视, 但是标准并不存在, 交换格式仍在争论中. And really, only NHK and Sony have deployed anything and it's astronomically expensive. 这东西在战场上不存在. On the client side, you have decoders on mobile devices that max out at 4K. And then of course in between you have the challenge of bandwidth.

你如何解决这些问题? 我们已经看到, 就在最近几个月, 360 capture devices on the market that can capture it 6K or 8K. 它们使用内置压缩芯片, 这在某种程度上损害了质量, but they get the data down to the point where it can be delivered. Then you run into the problem of broadcast production. 你不能再用4K开关了, there's no 6K switch that you can buy off-the-shelf at the local store. 黑魔法还不能制造一个. To get to to 6K or 8K, that workflow needs to be reinvented.

然后交货就成了问题, because you can't deliver a 50-megabit stream today, 或者明年, 或者再过一年, 或者再过一年. Even if you could do it, it's probably not economical.

怎么解呢? That comes down to what's variously attributed as viewport-adaptive streaming or field-of-view streaming. 对于那些不熟悉这个的人, 这类似于自适应比特率流, 除了, instead of having different bitrates you send different parts of the sphere at different resolutions.

There are multiple implementations for this in the market now. 有一个进程内的MPEG OMAF标准, 一种定向媒体格式标准, 这本书将于今年晚些时候出版.

Nokia has developed our tile media standard, which has the benefit of being very simple. 它不需要更改编解码器, no changes to the CDN; it's simply a protocol for defining in the manifest how a sphere can be broken up into separate tiles that are delivered as separate streams, 在客户端组装. It has already been implemented by a couple of vendors. 我知道和声在仔细调查, and has done some implementation on some similar schemes as well.

There will be some announcements from Nokia in the coming weeks. 不幸的是，我现在不能做一个, but very soon you'll hear more from us about how we hope to enable the community to use this standard more broadly, mostly as a stopgap between now and the time when OMAF and the proper standards emerge from the standards bodies. 这是很容易实现的.

结果是, you don't deliver the full sphere at full resolution, 结果不仅是一个较低的比特率, 没有其他变化, 你可以节省40-50%的比特率, 而且对客户也有很大的好处. So the client doesn't have to decode the entire sphere, and this allows you to drive higher resolutions to 6K, 甚至是8K单镜, 6 k立体, 在只有4K硬件解码器的设备上, because you don't actually have to decode the entire frame all at once.

The result is that in 2018 you will see in 2018 the emergence of 6K, 8K broadcast-capable pipelines. 这是第一步, 就在三周前, we worked with several partners to deploy at the Oculus Connect conference, 第一个, 据我所知, 这是第一个拥有双4K的公开直播, 每只眼睛满4K, 有现场混音音频吗, 并且有viewport-adaptive streaming. So we were delivering 4K per eye at about 12 megabits a second. That’s twice the resolution that we had here not even a year ago, at half the bandwidth.

这些进步正在进行中. The bigger challenge then becomes, as I mentioned before, the broadcast production pipeline. How do you do a proper broadcast at 6K, or 8K, or 8K stereo? Those tools don't exist, so that becomes the next hurdle.