Dedicated Streaming Servers: Live Video Hosting Guide

Reliable hosting of live video is a matter of few specifics: adequate amount of upload bandwidth, right protocol, method of reaching viewers at varying connectivity and approach to load distribution. The following guide sheds some light on all of them.

What makes a dedicated server suitable for hosting a live video stream?

The upload bandwidth adequate to host the live video ingest feed, right protocol that supports the feed sent by your encoder and access point to the CDN which allows reaching the viewers. Even though a server suitable for hosting a website is far from being suitable for hosting live video feed.

Our own network supports up to 100Gbps, the kind of headroom a live video ingest feed needs rather than a connection already shared with other traffic.

A live video feed requires some extra consideration from the side of dedicated server, even though its specifications may seem adequate for web hosting. In fact, a live video feed has its specific requirements and a server should meet all of them in order to host live video adequately.

What is RTMP, and why is it still used to ingest a live stream?

RTMP stands for Real-Time Messaging Protocol – it is a protocol that ensures low latency audio and video streams over TCP. This protocol is widely used to transfer a stream from your encoder to the receiving server.

According to Wikipedia's entry on RTMP, RTMP is "a communication protocol for streaming audio, video, and data over the Internet", which is "TCP-based" and therefore "maintains persistent connections and allows low-latency communication". As seen, this protocol is designed specifically for transferring live video streams.

What is adaptive bitrate streaming, and why does it matter for viewers?

Adaptive bitrate streaming is the method of encoding video at multiple bitrates, thus allowing each viewer to play the version of the video adequate to his/her current network connection. Without this method, a slow network connection would result in buffering instead of lower quality video.

According to Wikipedia's entry on adaptive bitrate streaming, this method "requires the use of an encoder which encodes a single source media (video or audio) at multiple bit rates" and the client-side algorithm decides "which bit rate segments to download, based on the current state of the network". Adaptive bitrate streaming provides for "very little buffering, faster start times and a good experience for both high-end and low-end connections".

Why does a CDN matter when distributing a live stream to a large audience?

Even though your server can ingest live video streams reliably, without a CDN you won't be able to distribute the stream to thousands of viewers. CDN is used in distributing the stream by spreading the load among various server nodes, located near each of the viewers.

According to Wikipedia's entry on content delivery networks, CDNs are "a geographically distributed network of proxy servers and corresponding data centers," and request routing "directs client requests to the content source best able to serve the request," often "the service node that is closest to the client".

How much upload bandwidth does a live streaming server actually need?

It depends on resolution and frame rate, starting from around 4 Mbps for 720p and ending with 35 Mbps for 4K at 60 fps. This figure is only for the ingest side, not for delivering the stream to viewers.

As you see, these figures vary depending on video resolution and frame rate. They are taken from YouTube's own live encoder settings guide and according to this guide you should "choose a quality that will result in a reliable stream based on your internet connection". Excess is better than deficit in this case.

Our Bare Metal servers and VPS plans are developed in such a way to have adequate upload bandwidth for live video ingesting. So you'd better configure your encoder settings accordingly to the figures above before broadcasting your live video.