In this article, we discuss streaming specifically to Facebook. Streaming to other platforms such as YouTube, Vimeo, your church’s website or distribution platforms like Resi or Boxcast have separate requirements and will yield different results.
Why is Facebook Different?
To begin, Facebook is a multi-purpose platform. While it does support live streaming, that is not the core function of the platform - its primary purpose is to populate and manage posts and news feeds. A massive amount of network traffic and server utilization is required to manage and distribute millions of posts, maintain Marketplace, Chat, Groups and Stories. All of these features tax the infrastructure systems in place. Juxtapose that with YouTube whose entire platform is built around archiving and delivering video content. Live Streaming on Facebook is secondary. Therefore, they have implemented protocols to ensure that each feature set available on the platform remains functional, even during peak usage.
What Changed?
Prior to the Spring of 2020, Facebook was rather lax on its live streaming requirements. Bitrates and resolutions had much looser restrictions; however, when usage spiked exponentially in March and April 2020, new measures were implemented in order to handle the increase in traffic.
What Does Facebook Support and Recommend for Live Streaming?
Resolutions: 720p and 1080p
Frame Rate: 30 and 60 FPS
Bitrate: 3000-6000 Kbps. In many instances they place a cap at 4000 Kbps.
Codec: H.264
Protocol: RTSP
For more information directly from Facebook, check out their support article.
So How Do We Get the Most of Our Live Stream?
The biggest limiting factor to consider here is the Bitrate restriction. This is a limit of the amount of data per second that the stream can contain. On Sunday mornings, when churches around the world are uploading content, it isn’t uncommon for Facebook to limit rates to 4000 Kbps. Ultimately, we have 3 factors involved - Resolution, Frame Rate and Bitrate. The higher the resolution, the more individual pixels are included in the image. The higher the frame rate, the less motion blur or “jitter”. And bitrate indicates how much data is available to fit all of that information into. Here’s an analogy.
As you increase the resolution and frame rate of the original video signal, you increase the amount of information contained within each frame of the original image. In simpler terms, we are trying to push a fire hydrant’s worth of water through a garden hose. We have a fixed limit on the amount of data we can stream - the garden hose. But most of our systems are capable of incredibly high resolutions, frame rates and bandwidth.
The higher we set our Resolution and Frame Rate, the more bandwidth we need. If we max out both of those settings, we are spreading out the available bandwidth really thin. It’s a “Data per Pixel” challenge. In order to maintain as much quality in the image as we can, we want our stream to be compressed as little as possible once it leaves our booth. As counterintuitive as it seems, we may need to reduce the resolution and frame rate in order to get the best quality out of our image. In almost every instance, reducing the overall bandwidth of the stream before uploading yields a higher quality image than allowing Facebook to compress it for you. A feed at 720p30 is going to require a fraction of the amount of data as 1080p60. That means that it will require less compression in order to get through the pipe that Facebook is giving us. Less compression downstream means that we keep more of our original quality.
Overall, the goal is to maintain as much quality as possible from beginning to end. Don’t be afraid to test different resolutions, frame rates and bitrates to determine what works best for you. Knowing the limitations initiated by Facebook may help narrow down the challenges.