OBS Studio Gets a New Renderer

Summary

Starting with OBS Studio 32.0.0 a new renderer backend based on Apple's Metal graphics API is available for users to test as an experimental alternative to the existing OpenGL backend on macOS. This marks an important step in OBS Studio's development to adapt one of the modern APIs that deliberately broke with the past to unlock better performance and efficiency gains for end users, but also require fundamental changes to how an application interacts with a GPU. These fundamental changes were necessary to achieve the goals of lower overhead, faster performance, and to better represent the way that modern GPUs actually work, particularly when the GPU is used for more than just 3D rendering. Yet other changes were also necessary due to the way Metal was specifically designed to fit into Apple's operating systems. Due to the sheer amount of information around this topic, it made sense to split it into separate posts: The first post (this one) will go into specific challenges and insights from writing the Metal backend for OBS Studio. The second post will look at the history of 3D graphics APIs, their core differences, and how the design of the new generation creates challenges for existing renderers like the one in OBS Studio. The Metal backend is explicitly marked as "Experimental" in the application because it has some known quirks (for which no good solutions have been found yet, more about that below) but also because it has not yet been tested by a larger user audience. The OpenGL renderer is still the default choice offered to users and will be available for the foreseeable future, but we still would like to invite users to try out the Metal backend for themselves, and report any critical bugs they might encounter. Better yet, if you happen to have prior experience working with Metal on Apple Silicon platforms (including iPhones), we'd be happy to hear feedback about specific aspects of the current implementation or even review pull-requests with improvements to ...