The Hazards of Streaming Live Video: If It Can Fail, It Will Fail

当我受雇为客户网络直播活动时, I like to believe that I’ve planned adequate levels of redundancy for nearly every aspect of the production. 我们的装备有备份，从摄像头, 镜头, 从麦克风到视频切换器和编码器.

对于编码管道, we standardize on having dual outbound internet connections, 每个编码器使用一个. 为我们的政府工作, we usually have access to two dedicated connections: an internal government backbone with more-than-sufficient bandwidth for 720p broadcasts and a local carrier connection such as a cable modem. 每一个小时.264或H.265/HEVC) encoder uses a dedicated connection, and the Wowza流媒体引擎 tech we’ve built allows an immediate switchover to the secondary encoder stream should the primary stream fail.

Having two connections is likely enough redundancy for just about any live streaming work we do, and I fully appreciate that not all scenarios will allow for having one, 更不用说两个了, 硬连线互联网连接. 在过去的几周里, 虽然, we’ve had issues with internet stability at venues where previously there were none—and because we were prepared, 我们手头的网络广播有最小的停机时间. I 虽然t it would be useful to readers to put some guidelines together for redundancy throughout the entire live streaming pipeline:

1. Prepare multiple networking options in advance of the live webcast.如果你在酒店或会议场所工作, ask just how dedicated your internet connection will be. 他们有你可以使用的备用互联网提供商吗? 如果不是, look into the cost of hardware and data plans that can use multiple USB 3G/4G/ LTE modems such as those offered by Mushroom Networks or Teradek. I also like to prepare a single hotspot device such as a 中兴通讯Turbo Hub 作为第三个备份. 本质上, any networking appliance that can provide a wired Ethernet connection to an encoder can play a backup role.

2. Prepare more than one origin (or ingest) streaming media server. If you’re using a CDN or hosted streaming environment, make sure you have primary and backup publishing points, 每个编码器一个. If you like to build your own streaming server instances on the cloud, have two origin servers ready to receive the incoming streams from the server. You may want to have one origin on standby should the primary origin not be reachable (e.g., an Amazon Web Services region becomes unavailable due to a DDoS attack). Your edge servers need to be configured to locate the availability of streams on each of your origin servers.

3. Thoroughly test the throughput of each internet connection prior to the webcast. Run your encoders for at least 30 minutes to ensure that bandwidth is stable. 如果可能的话, monitor the incoming stream on your streaming server to see if bandwidth fluctuates wildly during the test. Be sure to run some “active” content during the test—encoders will not necessarily use the full bitrate you’ve specified if you’re simply pushing color bars and test tone. Run live camera feeds of the venue, preferably during a dress rehearsal of the event.

4. Thoroughly test the failover system prior to the webcast. Take each encoder offline to see how effectively your system works. 如果你有一个坚实的设置, you can bring each component back online without your live stream player displaying an error.

5. 是否有适当的灾难恢复计划. Write up a specification that anyone monitoring the encoding gear can follow in the event of a network outage. 备份也可能失败, and your clients should know in advance how you and your team will respond in the event of one (or more) network outages. You can extend this plan to include anything related to your production setup, 包括相机或麦克风故障.

If you have redundancies built into your live streaming checklist, you’ll know exactly how to handle any failure before it turns into a disaster.

[本文发表于2018年4月/ 5月号。 流媒体杂志 “互联网规则:如果它能失败，它就会失败。."]