Screenshot from the video game (own work). Image by Jordan Mechner, via Wikimedia Commons (CC BY-SA 4.0).

ClownMDEmu

SEGA MD/CD EMULATOR CORE

ClownMDEmu

ClownMDEmu is an open-source, libretro-core-oriented Sega Mega Drive / Genesis emulator with optional Sega CD support via its libretro frontend. The project emphasises portability, minimalism, and an integer-only C89 codebase; it is provided as a re-usable emulation core intended to be run inside frontends such as RetroArch or Clownacy's standalone frontend.

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Screenshot from the video game (own work). Image by Jordan Mechner, via Wikimedia Commons (CC BY-SA 4.0).

Sega MD/CDPRIMARY SYSTEM

History documentedPROJECT BEGAN

Open sourcePROJECT MODEL

WHY IT MATTERS

Why ClownMDEmu exists

ClownMDEmu was developed to be a lightweight, portable, and self-contained Mega Drive / Genesis emulation core that emphasises clean, integer-only C code, no dynamic allocation, and a small dependency surface. The core is designed so frontends handle platform specifics, audio mixing and display, while the core focuses on emulation primitives and exposing low-level audio/video outputs for flexibility.

BEST FOR

What ClownMDEmu is best for

Use ClownMDEmu when you want a small, actively maintained libretro core that is easy to build and integrate, or when you want a core that exposes low-level audio/video for frontends to handle mixing and resampling. It is a practical choice for RetroArch users who prefer a modern alternative to older MD/Genesis cores and for developers who want a portable emulation backend.

Gameplay from Sonic the Hedgehog on Sega Genesis.

The people behind ClownMDEmu

Development and status

ClownMDEmu is developed publicly by the author(s) under the Clownacy organisation on GitHub. The project provides a standalone frontend and a libretro frontend; the repository for the emulation core documents design decisions (C89, integer-only arithmetic, no global state, custom 68000 and YM2612 implementations) and a build process using CMake with git submodules. The libretro distribution and documentation show the core as an available libretro core for Sega MD/CD in the core list. Releases for the libretro frontend are published on the project's GitHub releases page and the project has an active issue tracker and changelog in its repositories.

What ClownMDEmu supports

RetroArch (libretro frontends) on PC
RetroArch on Android
RetroArch on iOS (where libretro builds are supported)
Standalone frontend (desktop builds from clownmdemu-frontend)

Download and availability

OFFICIAL DOWNLOADS

Get ClownMDEmu

Install the libretro core by either: (A) using RetroArch's Online Updater (preferred for most users) to download 'ClownMDEmu' if it's hosted by your RetroArch build, or (B) download prebuilt core releases from the clownmdemu-libretro GitHub releases page, or (C) build from the official GitHub repositories (see guide). The core and frontends are distributed from the project's GitHub repositories and documented on the Libretro documentation pages.

Get ClownMDEmu ↗

DOCUMENTATION

Official documentation

Read the official configuration, compatibility, and troubleshooting material before changing advanced options.

Read official documentation ↗

Broken or missing download? Emulator projects move and official links sometimes change. Please contact Retro Replay so the source can be verified and updated.

ClownMDEmu setup guide

Setup note: This setup guide covers using ClownMDEmu as a libretro core in RetroArch and building the core from source. It also covers practical Sega CD setup notes (BIOS and image formats). Follow the steps that match your platform and skill level.

Option A — Quick install via RetroArch (recommended): 1) Start RetroArch and go to Online Updater -> Core Updater. 2) Look for 'Sega – MD/CD (ClownMDEmu)' (or 'ClownMDEmu') and download the core. 3) Put your Sega CD BIOS files into RetroArch's system folder if you plan to run CD titles (see BIOS step). 4) Load the core: Main Menu -> Load Core -> select the ClownMDEmu core. 5) Load content: Main Menu -> Load Content -> navigate to your cartridge ROM (.bin/.smd/.gen/.md) or CD image (.cue/.iso/.chd). For Sega CD games use the .cue sheet approach or CHD images when possible; use the core settings menu (Core Options / Load CD Image) if present to select disc images.
Option B — Download prebuilt libretro core: 1) Open the clownmdemu-libretro GitHub releases page and download the release artifact that matches your platform/RetroArch core format (e.g. .so/.dll/.dylib). 2) Place the core binary in RetroArch's cores folder, then open RetroArch and load it (Main Menu -> Load Core -> Select File). 3) Configure system/BIOS folder path in RetroArch's Settings -> Directory -> System/BIOS and place required BIOS files there (see BIOS step).
Option C — Build from source (libretro core): 1) Clone the libretro frontend repository: git clone –recursive https://github.com/Clownacy/clownmdemu-libretro.git (the core repo uses submodules; use –recursive or run git submodule update –init). 2) Follow the repository's README build instructions; the core and frontend are designed to build with CMake. 3) Ensure required submodules are present (use git submodule update –init –recursive) and select the correct target for your platform (Windows, Linux, macOS, Android). 4) After building, copy the produced libretro core file into your frontend's cores folder and proceed to load content in RetroArch or another libretro frontend.
Sega CD BIOS files — required for accurate CD emulation: Many Sega CD games require the official Sega CD BIOS files placed in your frontend's system/BIOS folder for correct booting. Common BIOS filenames used by libretro-based setups are bios_CD_U.bin (US NTSC), bios_CD_E.bin (Europe/PAL), and bios_CD_J.bin (Japan). The BIOS files are not distributed with ClownMDEmu; you must obtain them from your own legally-owned hardware. After placing BIOS files, verify in RetroArch's Core Information (Main Menu -> Information -> Core Information) that the firmware entries show as Present before attempting to boot CD content.
Loading CD content (format and tips): Use a .cue file that points to one or more .bin files, an ISO, or CHD (compressed disc) images. If using .cue/.bin pairs, ensure the cue path references are correct and that all referenced bins are together with the cue. Some frontends offer 'Load Disc' or a 'Load CD Image' core option — use it if present. If you see 'failed to load content', double-check BIOS presence, image format, and that you loaded the core before loading the content.
Core options and troubleshooting: Open the RetroArch Quick Menu (while a core is loaded) to access Core Options for ClownMDEmu if available. Use the core's debug or logging outputs when building from source or running the standalone frontend to diagnose missing firmware or image parsing issues. If CD audio or FMV appears desync'd, try a CHD image or check the frontend's audio latency settings. For feature gaps consult the core's TODO and issue tracker on the project's GitHub.

Software reminder: ClownMDEmu is licensed under AGPLv3; the core does not include commercial game ROMs, CD images, or console BIOS files. Obtain BIOS and game images only from media you legally own.

Sources and further reading

Detailed guides and tutorials

Explore step-by-step guides for ClownMDEmu as they are published.

Use ClownMDEmu on Android

An Android ARM64 Libretro build exists for ClownMDEmu. Run the core through RetroArch for Android; the standalone desktop download and Android core may have different menus and features.

Emulates: Sega CD.

Verified Android core build ↗ · Browse all Android emulators →