Glare node flickering

Hi everyone!

I’m working on a scene where a camera flies through a star cluster. I’m using a particle system to set up the stars (icospheres with emission shader), and then in the compositor, using glare nodes to give the stars ‘points’.

However, there is some major flickering going on in the glare! I’m not sure what the problem is. Any ideas?

Here’s a screenshot of frames 1 and 2, next to each other. You can see for example the glare on the blue star flashes between them.

Screen Shot 2020-03-02 at 6.53.02 PM

Here’s a short video of the flickering:

And here’s the Blender file if you want to poke around:

Thanks for your time!

Because those moving stars are so tiny, your glare input is getting unstable intensity values from the render layer. Sometimes the pixels are bright enough to be over the threshold; other times they’re not.

You can improve the accuracy of the frames by increasing your samples, or you can turn down the threshold of your glare node so that the intensity of the stars is more reliably past the threshold value.