Developed multi-threaded audio processing support for the sdl2_mixer library within the emscripten-core/emscripten repository, focusing on enhancing performance in concurrent environments. The work involved introducing new build flags and variants to enable multi-threading, allowing audio tasks to run in parallel and improving efficiency for cross-platform applications. Leveraging expertise in build systems and C/C++ libraries, the developer validated the build pipeline to ensure robust integration of these features. Python was used alongside C/C++ to manage and automate aspects of the build process. The contribution addressed a key performance need, demonstrating depth in cross-platform development and build system optimization.