Multiple cores on Linux

:::info This document is outdated. As of 4.0.137, the default behavior is to use multi-process mode.
The setting still exists, but is true by default. :::

By default, Remotion starts the Chromium browser on Linux with the --single-process flag. This is because:

• The sandboxing feature of Chromium is not supported on all Linux distributions
• Older versions of Chromium used to crash when starting headlessly with multiple processes
• If some desktop libraries are missing, Chromium could crash on startup on some Distros.

This can lead to degraded rendering performance, especially when trying to leverage high-core CPUs and high Remotion concurrency.

Enable multi-process rendering on Linux

available from v4.0.42

Enabled by default. To disable multi-process mode for Chromium during rendering on Linux:

• renderMedia() / openBrowser() / renderFrames(): Use the chromiumOptions.enableMultiProcessOnLinux option.
• CLI: Use the --enable-multi-process-on-linux=false flag.
• Config file: Use the Config.setChromiumMultiProcessInLinux() option.
• Remotion Studio: Check the toggle in the advanced settings.
• Cloud Run: From v4.0.42, this option is automatically enabled.
• Lambda: This option is disabled with no option to enable it because on Amazon Linux, Chrome will crash if the --single-process flag is not used. We recommend using more Lambdas instead of more concurrency per Lambda.

Should I enable multi-process mode?

The answer depends on the Linux environment. If you are running Remotion on a server, you should try to enable multi-process mode and see if it works.

Our recommended Docker image is confirmed working with multi-process mode enabled.

See also

• Chromium flags
• Dockerizing a Remotion app