OBS Studio 32.1 introduced WebRTC simulcast, a new feature that gives streamers another way to stream live video over the internet. It's not something a lot of people use, but it works with services that support WHIP and WebRTC. Unlike typical streaming, WebRTC is designed for real-time communication and can provide very low latency. Simulcast takes this a step further, letting OBS send multiple quality versions of the same stream at the same time. It probably still sounds a little complicated, so we'll dive a little deeper below.
Takeaways:
- Learn how to set up WebRTC Simulcast to send multiple quality versions of your stream to streaming platforms like Twitch.
- What is WHIP in OBS Studio, and how does it connect OBS to compatible streaming services?
- Using WHIP and Simulcast in OBS Studio to send out multiple different quality streams to streaming platforms like Twitch.
Table of Contents
What Is WebRTC Simulcast in OBS Studio?
Simulcast lets OBS send multiple versions of your video to a compatible WHIP server. Each version, known as a layer, has a different resolution and bitrate.
For example, a three-layer configuration can send:
- A full-resolution stream at 100% of your configured bitrate.
- A second stream at 66% resolution and bitrate.
- A third stream at 33% resolution and bitrate.
OBS supports between one and four layers. With four layers, the additional streams use 75%, 50% and 25% of the main resolution and bitrate. There are a lot of benefits of using Simulcast, but it really depends on your hardware and the place you are streaming to.
- Lower latency: Avoiding an additional transcoding stage can reduce delay.
- More control: You control the encoding settings used to create the different layers.
- Potentially better quality: Encoding from the original source can avoid some generational loss associated with transcoding.
- Simpler infrastructure: A compatible server does not necessarily need to create multiple versions of the stream itself.
To put it as simply as possible, it lets OBS send the same video in three or four different quality levels at the same time, so viewers can receive the version that suits their connection.
What Is WHIP?
Before setting up simulcast, you also need to know about WHIP. It stands for WebRTC-HTTP Ingestion Protocol and provides a way for OBS to send your stream using WebRTC. OBS's simulcast feature works through WHIP, so you'll need a WHIP-compatible streaming service to use it. It's also worth mentioning that YouTube doesn't currently support WHIP. At least at the time of writing this.
How to Set Up WHIP in OBS
You will first need a WHIP service that provides you with a server URL and bearer token.
- Open OBS Studio.
- Open Settings.
- Select Stream.
- Set Service to WHIP.
- Enter the server address provided by your WHIP service.
- Enter the Bearer Token supplied by the service.
- Apply your settings.
The bearer token is essentially the WHIP equivalent of a stream key. OBS recommends obtaining both values from your chosen WHIP provider.
How to Use WebRTC Simulcast in OBS Studio
Once your WHIP connection is set up, you can configure simulcast from the same Stream settings.
- Open Settings > Stream in OBS.
- Find the simulcast settings.
- Choose how many quality layers you want to send (1-4)
- Set up the layers according to the requirements of your WHIP service.
- Apply the settings.
- Start your stream and check the receiving service.
Remember: OBS allows between one and four layers. The additional layers are automatically based on percentages of your main resolution and bitrate rather than requiring completely separate encoder configurations.
