RetroArch

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Note: RetroArch is not affiliated with Arch Linux.

RetroArch is the reference implementation of the libretro API. It is a modular front-end for video game system emulators, game engines, video games, media players and other applications that offers several uncommon technical features such as multi-pass shader support, real-time rewinding and video recording (using FFmpeg), it also features a gamepad-driven UI on top of a full-featured command-line interface.

Installation

Install the retroarch package or alternatively retroarch-gitAUR for the development version.

Tip:

Usage

RetroArch relies on separate libraries, called "cores", for most of its functionality. These can be downloaded per-user within RetroArch itself (via the libretro Buildbot) or you can install them system-wide via Community or AUR.

By default RetroArch is configured to load the per-user cores that it downloads. Change your #Configuration if you install them elsewhere.

The command to run a particular core is 

$ retroarch --libretro /path/to/some_core_libretro.so /path/to/rom

Configuration

When you first run RetroArch it will create the user configuration file ~/.config/retroarch/retroarch.cfg.

If you install RetroArch components in your home-directory, you should specify local paths in the global configuration file for downloading cores. For example, 

~/.config/retroarch/retroarch.cfg
libretro_directory = "~/.config/retroarch/cores"
libretro_info_path = "~/.config/retroarch/cores/info"

If you install any RetroArch components system-wide with pacman, you should specify these in the global configuration file and include them in your user file. For example, 

/etc/retroarch.cfg
# for retroarch-assets-xmb
assets_directory = "/usr/share/retroarch/assets"
# for libretro-core-info
libretro_info_path = "/usr/share/libretro/info"
# for libretro cores
libretro_directory = "/usr/lib/libretro"
~/.config/retroarch/retroarch.cfg
#include "/etc/retroarch.cfg"
Note: RetroArch does not support multiple search paths for these components. For example, if you install cores with pacman and download cores using RetroArch's GUI, you cannot configure RetroArch to show all of them at once since they are installed in different directories.

If you want to override your configuration (for example when running certain cores) you can use the --appendconfig /path/to/config command line option.

Tips and tricks

Enabling the Online Updater

If you prefer to install all RetroArch components with the built in updater instead of pacman, you can enable it with a configuration file: 

~/.config/retroarch/retroarch.cfg
menu_show_core_updater = "true"
Note: Install libretro-core-info to ensure the core downloader works correctly. Without this package it will not fetch the core list to choose from.

Enabling SaveRAM Autosave Interval

By default, RetroArch only writes SRAM onto disk when it exits without error, which means that there is a risk of losing save data when using crash-prone cores. To change this behavior, open ~/.config/retroarch/retroarch.cfg and set autosave_interval to n. 

~/.config/retroarch/retroarch.cfg
autosave_interval = "600"

With the example above, RetroArch will write SRAM changes onto disk every 600 seconds.

Warning: Setting this value too low will cause all sorts of issue, most notably hardware degradation. See [1]

Filters and shaders

RetroArch can load BSNES XML filters and CG shaders. These are set in retroarch.cfg with video_bsnes_shader and video_cg_shader respectively. The shaders can also be obtained and updated directly inside RetroArch using the Online Updater.

Note: retroarch-gitAUR requires nvidia-cg-toolkit in order to use the cg shaders.

Reset settings to their default value

To reset a setting or keybind to its default value through the GUI, highlight it and press Start. To remove a button from a keybind, highlight the keybind and press Y.

Troubleshooting

No cores found

By default RetroArch searches for cores in ~/.config/retroarch/cores, which is where the Online Updater installs them. Cores installed with pacman are placed in /usr/lib/libretro and thus will not appear in RetroArch's GUI. You should choose one method of installing cores (pacman or the Online Updater) and change your #Configuration to match.

Input devices do not operate

You may encounter problems if running on a CLI or a display server other than Xorg or if you use the udev input driver, because /dev/input nodes are limited to root-only access. Try adding your user to the input user group then logging in again.

Alternatively, manually add a rule in /etc/udev/rules.d/99-evdev.rules, with KERNEL=="event*", NAME="input/%k", MODE="666" as its contents. Reload udev rules by running: 

# udevadm control --reload-rules

If rebooting the system or replugging the devices are not options, permissions may be forced using: 

# chmod 666 /dev/input/event*

Poor video performance

If poor video performance is met, RetroArch may be run on a separate thread by setting video_threaded = true in ~/.config/retroarch/retroarch.cfg.

This is, however, a solution that should be not be used if tweaking RetroArch's video resolution/refresh rate fixes the problem, as it makes perfect V-Sync impossible, and slightly increases latency.

Audio issues with ALSA

When using ALSA the audio_out_rate must match the system's default output rate, usually 48000.

Save data is lost whenever RetroArch crashes

See #Enabling SaveRAM Autosave Interval.

Start game from playlist but reports 'No Items'

If RetroArch reports "libretro core requires contents, but nothing provided", try to load game by manually chose the path of the ROM from the "Main Menu -> Load Content". It seems unreliable to start game from 'playlist'.

See also