|Authors:||Squarepusher, themaister, others|
RetroArch is an open-source, multi-platform frontend for the libretro API. It is designed to be fast, lightweight, and portable. Although not technically correct, its functionality with emulator-based Libretro cores makes it viewed as a multi-system emulator.
RetroArch is available for Windows, OS X, Linux, Android, iOS (jailbroken), BlackBerry 10, Raspberry Pi, OpenPandora, PlayStation 3, PSP, Xbox, Xbox 360, GameCube, and Wii. There are also preliminary 3DS ports, though most of them need a *New* 3DS if they are to work properly, a few of these requiring installation in the .cia format.
- RetroArch Stable Builds
- RetroArch Nightlies
- Windows RetroArch-Nightly-Installer
- Ubuntu PPAs: Stable, Nightly/Testing
- Arch Linux User Repositories: Stable, Testing, All, libretro-super
- RetroArch for Android
- RetroArch for PS3 (CFW) and PS3 (DEX) v.188.8.131.52
- RetroArch for Xbox and Xbox 360 v.184.108.40.206
- RetroArch for BlackBerry 10
- Main article: libretro#Cores
- Consistency across multiple systems.
- Custom resolution and refresh rate for output.
- Dynamic rate control for amazing sound even when it's run at a different rate than the video, such as vsync causes sometimes. Especially obvious with GBA.
- Basic fast forward, rewind, savestate, etc
- Shaders: .shader, .cg, .cgp . filter
- Custom overlay support.
- GGPO-like netcode (latency hiding rollback). It should be lag-free if everyone involved emulates at full speed, doesn't live on opposite sides of the world and has decent internet speeds. It uses peer-to-peer UDP and supports two players. Due to rollback it requires a fair amount of CPU power to run.
- Options for decreasing input latency related to vsync by eliminating buffering by the video driver as well as using frame delay.
- Main article: Using RetroArch
You must specify whether you will be hosting (server) or joining (client) the game. If joining, you must also enter the host's IP address in the field below. Make sure your firewall is open on port 55435 (default; you can change it if you like) and that the port is forwarded in your router, if applicable. You can also specify 'spectator mode,' which will allow an arbitrary number of spectators to join and watch you play without being able to play themselves.
Delay frames denotes the maximum number of frames RetroArch will need to emulate at once to maintain synchronization due to actual network latency. You can figure out an appropriate ballpark for this number by pinging the other player and dividing the time (in milliseconds) by 16 (roughly the number of milliseconds in a frame from a game running at 60 fps). If the gameplay is a bit choppy, try increasing the number of delay frames a bit.
Similar to the GGPO platform, RetroArch creates a constant stream of savestates which, along with button presses, are exchanged and compared between the server and client machines. If the savestates start to diverge, the game rolls back in time to a point where they both agree and then emulates the missing frames all at once to get back to the appropriate spot. This gives the illusion of completely lagless inputs, which is invaluable for twitchy, fine controls.
If you try to connect to a server and it immediately says client disconnected, open your log and make sure your ROMs match exactly (it will complain about a hash mismatch otherwise). If it gives you a weird time-out error, just close the window and try to connect again and it should work itself out (sometimes excessive spikes in network latency can cause the states to diverge catastrophically, resulting in this error).
There is an alternate launcher available called RAEM (formerly known as RA-Player), for those that want to try something that looks more like a native Windows program. It hasn't been updated in a while, though. Download it here
There is also a promising alternative frontend for libretro cores that is independent of RetroArch and is GUI based called Phoenix. Don't confuse it with the old Phoenix Launcher for Libretro. It is still in early development and requires that you build it yourself through QT, though the main developer says an alpha release with prebuilt binaries is on the way.
Available here: https://github.com/team-phoenix/Phoenix