Process quit with signal SIGKILL

This error comes in multiple variants:

Remotion Rust process killed
Compositor quit with signal SIGKILL: [...]

FFmpeg process killed
FFmpeg quit with code null (SIGKILL)

What is happening?

The operating system is either killing the Remotion process or the FFmpeg process.
Most likely this is due to it taking too much memory.

Memory management in Remotion

Remotion opens a cache for extracting video frames, which by default allows itself to fill up to 50% of the available memory used at the begin of the render.
If Remotion realizes that the system is short on memory, it will halfen the cache size and free up memory.

However, if other processes are filling up memory, the Remotion process can be killed as soon as it allocates any memory.
The same goes for the FFmpeg process.

Lower the memory usage of Remotion

You can decrease the cache size of Remotion using the offthreadVideoCacheSizeInBytes.

Ensure your Remotion version is up to date

We continuously improve the memory management of Remotion.
The last version with improvements is v4.0.171.

Lower the concurrency of Remotion

Set a lower concurrency to open less browser tabs at once and thus less memory.

Disallow parallel encoding

Parallel encoding encodes video while frames are still being rendered, so the browser and FFmpeg need memory at the same time. Use the disallowParallelEncoding option to only start encoding once all frames are rendered. This lowers the peak memory usage, but may make rendering slower.

Allocate more memory to your system

As a last resort, you can allocate more memory to your system to alleviate the problem.