2016年4月5日
By 1月时特约编辑
专题文章

如何选择直播模式

观众在移动设备上观看越来越多的流媒体视频, 这给所有百家乐软件app最新版下载带来了两个现实. 第一个, 你必须提供自适应比特率(ABR)视频, 所以你可以取悦那些通过高带宽连接观看的人, 同时为那些通过手机观看的人提供足够的体验. 第二个, though it’s possible to deliver one format of ABR packaging to computers and 移动设备, most publishers use two or even more: HTTP Dynamic Streaming (HDS) or MPEG-DASH to desktops, 以及移动端HTTP直播(HLS). I look at how to meet this challenge for VOD content in “Encoding and Delivering to Multiple ABR Formats” (see page 168). 在本文中，我将探讨直播的含义.

Live event producers have two basic approaches for producing and delivering multiple ABR 包s: You could purchase an expensive encoder/transcoder and provision sufficient outbound bandwidth to encode onsite and deliver all streams to the cloud for distribution. Or you could send a single stream out to the cloud for transcoding into the multiple files in your adaptive group, 然后将其打包(或“transmuxed”)到必要的ABR包中. 如果你是全天候流媒体，拥有自己的设备通常是有经济意义的. 对于大多数其他生产商来说，云转码可能是一条可行之路.

在本文中, I explore the cloud transcoding/ packaging options available to two classes of live event producers. 第一个类只是想放弃所有的直播任务, 从转码到播放器创建再到视频传送, 给第三方服务提供商. 第二个有一个现有的直播工作流, 或者想要建造一个, and simply wants to acquire cloud transcoding and packaging to insert into that workflow. 每个组的成员, 我确定了他们应该考虑的服务提供商类别, 并确定一些选项和区别特征.

开始之前, let’s briefly identify the steps in the live event production workflow that must be performed, 要么是你, 或者由服务提供商代表您. 这将有助于区分下面讨论的备选方案.

现场生产. This is the audio/video creation step and includes obtaining the necessary A/V gear and the operators to run it.

现场编码. Taking the signal from the camera or video mixer and encoding it for delivery to the cloud. 信号传输. 将编码信号传送到云端进行转码和封装. 码/包装. Transcoding the incoming stream into the different quality levels and packaging them for playback on the various target platforms.

源服务器. 为查看器访问流提供服务器.

交付. Delivering the streams to the viewers, typically via a content delivery network (CDN).

玩家开发和维护. Creating the player used to view the live stream and to interact with the producer, 其他观众, 还有社交媒体. 这个因素既关键又复杂, because it involves achieving and maintaining compatibility with all target PCs, 移动设备, 以及其他平台.

Now that we know the components of a live event, let’s examine your service-provider options.

直播服务提供商

简介: Your organization is using video as a tool, rather than a product or service. You want to stream one or more live events and you’re looking for a service provider to input your single live stream, 然后自动译码系统, 包, 然后把视频发给你的目标观众.

最佳搭配: Your best match will be one of a group of companies roughly called live streaming service providers (LSSP). 这个多元化的群体包括Ustream, 转播画面, DaCast, 和YouTube Live, companies that make it simple for nontechnical users to stream to the masses. Some traditional online video platforms (OVPs) also offer live streaming services, Wowza最近推出了Wowza流媒体云, 一种灵活的服务，将与广泛的潜在用户基础相关.

所有服务输入您的直播流, 转码并打包它们, 然后传递给你的观众. 大多数人在该服务上创建了一个页面，观众可以在那里观看直播, 同时也允许你在自己或第三方网站上嵌入播放器. 基本上，你提供输入流，他们做剩下的.

郑重声明, 我应该注意到转播画面不执行实时转码, so you have to encode and deliver all streams to the service that you want to distribute to your viewers. I include 转播画面 in the article because it has some interesting features and is one of the best-known companies in the space.

预估定价模型

This pricing model from DaCast is pretty typical of those offered by the LSSP group.

如何选择服务: Here are the key questions to help identify the best solution for your organization.

我的支持选项是什么?它们的费用是多少? 免费就是好, until there’s a problem at the live event you’re producing and there’s no number to call. This simple reality removes YouTube Live from the equation for many producers. 与其他服务一起, 检查每个定价层可用的支持级别, and give precedence to services that offer phone support during the times you’ll be broadcasting.

这要花多少钱啊? Both classes of users will have to bone up on their spreadsheet skills to differentiate between the service providers. 在这个课堂上, 影响定价的因素包括播放时间, 传输了gb的视频, 观看时间. 显著, 转播画面 is one of the few service providers that offers unlimited pricing on some plans. 如果你担心病毒式传播会让你倾家荡产, 这使得转播画面成为一个非常有吸引力的选择.

我可以使用自己的品牌吗? Some systems don’t let you disable their branding, which makes sense for a totally free service. Other systems offer a “white-label” player that you can brand as your own at certain commitment levels.

用户体验如何? Does the player offer DVR functionality, so the users can pause the stream to take a break? 玩家是否支持聊天、评论和访问社交媒体? 特性集是如何变化的, 如果有的话, if the video is watched on an embedded player as opposed to the player on the service’s website? 除了品牌, how much can you customize the player to integrate its appearance with your own website?

我的盈利选择是什么? 如果你打算通过你的视频赚钱，一定要检查可用的选项. 例如, DaCast 是为数不多的提供按次付费功能的服务提供商之一吗. 其他公司则提供广告插入支持. 如果盈利对你的现场活动至关重要，那就尽早提出这个问题.

Wowza流媒体云