实时编码的关键注意事项

随着越来越多的直播内容在各种不同的设备上被消费，包括低端和高端手机和平板电脑, 以及智能电视和支持4k的机顶盒(stb)——围绕选择直播编码器的决定变得越来越复杂.

考虑到这样一个事实:大量的流媒体直播观众将在至少两台设备上观看单个直播事件——无论是坐在舒适的客厅里, 在智能电视上观看大赛, while also interacting with “watch party” friends on a second screen, 或者只是在工作和家庭之间的交通中通过移动设备观看部分活动——很容易看出，直播工作流程比四五年前要复杂得多.

设备之间的往返

幸运的是, 二十年来，面向消费者的视频点播(VOD)流媒体工作流程添加了许多新功能，这些新功能使流媒体直播解决方案受益匪浅. 超越了基于http的交付的标准化, 由Adobe等公司开创, 苹果, 微软, 还有一些是十多年前的, user-focused VOD benefits are now available as standard options on most of today’s live streaming encoder platforms. 举个例子, consider how roundtripping content between devices has jumped from being a VOD-only feature to becoming
直播解决方案的赌注表.

VOD的往返好处解决了消费者的一个挫败感:当VOD内容在一个设备上开始观看并在另一个设备上完成时. Consumers had complained that they were forced to start at the beginning of the content on the second device, 手动搜索，直到找到同一个地点. 双向内容的出现(本质上是在设备之间共享的单用户播放列表中跟踪基于时间的指针)允许消费者开始在一个设备上观看内容，然后无缝地转移到另一个设备上.

在直播传输解决方案中, 这种往返的好处扩展到追赶服务(本质上是一种类似dvr的功能，允许观众在转换到另一个设备时错过几分钟的游戏), but “catch up” on that gap to check whether any major event occurred in the gap). 一些解决方案允许完整的事件追赶(例如.g., 主要体育赛事, inclusive of must-see commercials) while others allow for a minimal catch-up window of several minutes.

有很多挑战, 当然, several of which were 封面ed in a session at the recent 流媒体 East 2023 session on 迎接直播视频点播挑战, 但也有新的好处，直播追赶功能增加了创建关键事件的即时高光录像的能力, 然后以视频点播的形式传送.

一些内容所有者选择向非付费观众提供视频点播内容，以此吸引他们订阅或付费观看正在进行的按次付费活动. As an enhancement beyond the typical DVR-based catchup services or manually created highlight reels mentioned above, experience dealing with large-scale live events has brought about additional enhancements.

最近, 许多公司已经宣布了机器学习选项——通常使用术语AI或人工智能——旨在自动化制作和包装这些精彩的体育直播录像. 解决方案被编程来识别球的运动, 裁判的哨子, 人群怒吼, 以及关键比赛或进球的其他重要方面.

Given the higher likelihood that viewers will consume live-event content across multiple devices—whether at work, 首页, or in the transition between locations—the table stakes in encoding have risen significantly over the past few years. 确保从编码器到消费者的高质量原创流对于成功的直播流至关重要，特别是现在消费者要求具有内容质量期望的追赶功能，这种功能可以与具有多通道编码的VOD内容编码相竞争.

Ensuring Origination Stream Quality: Key Factors to Consider

So, what factors should be considered when attempting to ensure a high-quality origination stream? 每个实时事件流工作流都有相似之处, 但我在下面列出了一些需要考虑的关键因素.

场地带宽: Given the transitory nature of live-event content consumption, it’s not just the bandwidth issues on the consumer delivery front but also at the venue that need to be considered. 有许多解决方案旨在帮助处理间歇性网络可用性—大多数都是基于前向纠错的概念, 即使丢失了数据包，它也可以推断出部分内容——但没有什么比一个坚如磐石的IP内容获取网络更能保证现代编码器摄取的质量了.

编码参数: The choices you make when setting up a live-stream encoder are also critical in enhancing the viewing experience your consumers, 因此，选择一个实时流媒体解决方案，可以为非常低带宽的3G移动设备编码任何东西，一直到4K高动态范围(HDR)流，理想情况下是同时进行, as a way to save on both power consumption and processing time—is a key factor in your live streaming encoding and delivery workflow.

多个协议: Not only should the live encoder be able to handle the multiple bandwidths and resolutions required for viewers to properly experience your live event; it should also be able to handle multiple input (acquisition) and delivery (origin server) transmission protocols. 我们将在下面讨论收购, 但是在原始服务器前端, make sure the minimum delivery outputs 封面 at least classic RTMP as well as one of the several HTTP-based delivery options. 这种灵活性既可以提供原始流的冗余，也可以在选择流传输合作伙伴时增加灵活性，以帮助将流传输给所有观众.

可伸缩性: Besides planning for your live-event streams to reach every type of viewer device—desktop, 移动PC, 智能电视, 智能手机——可扩展性的问题可能是选择实时流编码器和流传输合作伙伴时的下一个主要关注点. Scaling up to meet viewership demand in the past was often seen as a “black art,” but the last two decades of live event streaming have generated a number of seasoned delivery partners. 与合作伙伴一起工作的好处是，他们不仅经历过类似的实时事件流的扩展，而且可能已经使用过您正在使用的实时流编码器, meaning they may make a number of suggestions on how to create the best origin stream.

收购决策: When it comes to content acquisition, the best device is the one that you have on hand. In some instances that might be a higher-end smartphone, 在其他情况下，它可能是一台笔记本电脑——请记住，在疫情封锁期间，有多少远程生产(REMI)是通过商用和消费笔记本电脑完成的——或者它可能是一组高端广播摄像机.

输入源: Most of today’s hardware-based live streaming encoders allow input via IP (including both Wi-Fi and Ether网), as well as via the standard digital video connectivity (such as SDI or HDMI), and many of these come in very compact—and reasonably priced, 用于功能集选项.

软件编码器: Don’t want to spend capital on buying a hardware encoder? 你很幸运, 由于新一代的基于软件的在线编码器提供了硬件编码器的许多功能，同时还提供了各种低延迟的采集, 双向视频，无论是FaceTime, 满足, Skype, 团队和其他一些人——以及平原, 旧的RTMP和新WebRTC流.

监控: Before and during any event, monitoring is a key component of your live streaming workflow. 这可以采取设备上监控的形式, which is a feature often included in hardware-based encoders, or it can be monitoring via an app provided by the hardwareor software-encoder solution. I’ve personally used one app-based monitoring solution for a very small hardware encoder, 哪一款具有超低延迟监控功能，在实时事件流公开之前捕获音频和视频同步问题被证明是有帮助的.

额外的百家乐软件

We’ve only hit the highlights you should consider when choosing a live event streaming encoder, 但这里有一些额外的百家乐软件. 几个 文章 在最近 2023流媒体源手册 封面 直播选项.

除了, this special checklist section includes an accompanying article, 《百家乐app下载》,” which follows this one and highlights additional considerations when selecting the right encoder for your workflow; I strongly encourage readers to review that article carefully while making purchasing decisions around live stream encoders and streaming delivery service partners.