Live streaming latency

 

Stream latency is the delay between your camera capturing an event and the event being displayed to viewers. When setting up your live stream, think about how the level of latency may affect your viewers. 

If you live chat with viewers, a lower latency is best to reply to viewer comments and questions. Note that with lower latency, your viewers may experience more playback buffering. 

If you don't interact with your audience, higher latency is not a problem.

Why is there a trade-off between latency and quality?

The lower the latency, the less read-ahead buffer the video player will have. The amount of read-ahead buffer is important because it's the main source of stream latency. With a lower latency, viewers are more likely to feel the issues between the encoder and the player.

Network congestion and other factors may also cause live streaming issues, which can delay your stream. Delays can happen even when you have a great network that can sustain your average streaming bitrate.

Generally, your viewers' player can handle these changes in Internet speed by keeping some extra live stream data. This function is called Buffer Health in Stats for Nerds. 

How to change live stream latency

In Live Control Room: 

1. Go to YouTube Studio. From the top right, click Create  Go live.
2. At the top, click Stream or Manage. Create a stream or open a scheduled stream.
3. From the stream dashboard, click Stream Settings. 
4. Under 'Stream latency', select your latency.

Webcam and mobile streaming are always set up for interactivity. You cannot set a live stream latency for them.

There are three options for live stream latency:

Normal latency

Best for: reduced viewer playback buffering.

Choose 'Normal latency' if you don't plan to interact with your audience. This option is the highest quality setting for viewers since it has the lowest amount of viewer buffering.

All resolutions and live features are supported at Normal latency.

Low latency

Best for: near real-time interactivity

Choose this option if you want low latency with minimal viewer buffering. This setting is a good balance between the other two options. 

This setting does not support 4K resolution.

Ultra-low latency

Best for: highly interactive live streams with real-time engagement

Choose this option if you want to maximise engagement with your audience. It may increase the chances of your viewers experiencing buffering.

This setting does not support 1440p and 4K resolutions.

Note: Live ingestion issues on your network will affect viewers more in this setting. Consider decreasing your ingestion bitrate to make sure that your network can sustain the stream.