Half-Life and Counter-Strike movement communities frequently record their videos with motion blur. However, doing that fast is not a trivial task.

I talk about what goes into good motion blur and let you play with the blur parameters. I then describe my GPU-accelerated solution for fast recording of these videos, and the technical issues I’ve faced implementing it. I also analyse the performance and overhead of this code on a slow and a fast laptop.

I describe the inner workings of my new video recording tool in bxt-rs. It can record in-game footage from Half-Life at 1920×1080@60 at up to 3 times faster than real-time on a reasonably powerful PC.

I explain the general principles of specialized video recording tools, show how the bxt-rs video recording integrates into the game loop, and how to share frame buffers between OpenGL and Vulkan. I then talk about how I implemented the color conversion, the video encoding step, and how I optimized the performance by using two threads and correct GPU memory types.