Universal Commandline Options

This section contains configuration options that are applicable to all MAME sub-builds (both SDL and Windows native).

Commands and Verbs

Commands include mame itself as well as various tools included with the MAME distribution such as romcmp and srcclean.

Verbs are actions to take upon something with the command (e.g. mame -validate pacman has mame as a command and -validate as a verb)

Patterns

Many verbs support the use of patterns, which are either a system or device short name (e.g. a2600zorba_kbd) or a glob pattern that matches either (e.g. zorba_*).

Depending on the command you’re using the pattern with, pattern matching may match systems or systems and devices. It is advised to put quotes around your patterns to avoid having your shell try to expand them against filenames (e.g. mame -validate “pac*”).

File Names and Directory Paths

A number of options for specifying directories support multiple paths (for for example to search for ROMs in multiple locations). MAME expects multiple paths to be separated with semicolons (;).

MAME expands environment variable expressions in paths. The syntax used depends on your operating system. On Windows, % (percent) syntax is used. For example %APPDATA%\mame\cfg will expand the application data path for the current user’s roaming profile. On UNIX-like system (including macOS and Linux), Bourne shell syntax is used, and a leading ~ expands to the current user’s home directory. For example, ~/.mame/${HOSTNAME}/cfg expands to a host-specific path inside the .mame directory in the current user’s home directory. Note that only simple variable substitutions are supported; more complex expressions supported by Bash, ksh or zsh are not recognised by MAME.

Relative paths are resolved relative to the current working directory. If you start MAME by double-clicking it in Windows Explorer, the working directory is set to the folder containing the MAME executable. If you start MAME by double-clicking it in the macOS Finder, it will open a Terminal window with the working directory is set to your home directory (usually /Users/<username>) and start MAME.

If you want behaviour similar to what Windows Explorer provides on macOS, create a script file containing these lines in the directory containing the MAME executable (for example you could call it mame-here):

#!/bin/sh
cd "`dirname "$0"`"
exec ./mame64

You should be able to use any text editor. If you have a choice of file format or line ending style, chose UNIX. I’ve assumed you’re using a 64-bit release build of MAME, but if you aren’t you just need to change mame64 to the name of your MAME executable. Once you’ve created the file, you need to mark is as executable. You can do this by opening a Terminal window, typing chmod a+x followed by a space, dragging the file you created onto the window (this causes Terminal to insert the full escaped path to the file), and then ensuring the Terminal window is active and hitting Return (or Enter) on your keyboard. You can close the Terminal window after doing this. Now if you double-click the script in the Finder, it will open a Terminal window, set the working directory to the location of the script (i.e. the folder containing MAME), and then start MAME.

Core Verbs

-help / -h / -?

Displays current MAME version and copyright notice.

-validate / -valid [<pattern>]

Performs internal validation on one or more drivers and devices in the system. Run this before submitting changes to ensure that you haven’t violated any of the core system rules.

If a pattern is specified, it will validate systems matching the pattern, otherwise it will validate all systems and devices. Note that if a pattern is specified, it will be matched against systems only (not other devices), and no device type validation will be performed.

Configuration Verbs

-createconfig / -cc

Creates the default mame.ini file. All the configuration options (not verbs) described below can be permanently changed by editing this configuration file.

-showconfig / -sc

Displays the current configuration settings. If you route this to a file, you can use it as an INI file. For example, the command:

mame -showconfig > mame.ini

is equivalent to -createconfig.

-showusage / -su

Displays a summary of all the command line options. For options that are not mentioned here, the short summary given by “mame -showusage” is usually a sufficient description.

Frontend Verbs

Note: By default, all the ‘-list‘ verbs below write info to the standard output (usually the terminal/command window where you typed the command). If you wish to write the info to a text file instead, add this to the end of your command:

> filename

where filename is the name of the file to save the output in (e.g. list.txt). Note that if this file already exists, it will be completely overwritten.

Example:mame -listcrc puckman > list.txt

This creates (or overwrites the existing file if already there) list.txt and fills the file with the results of -listcrc puckman. In other words, the list of each ROM used in Puckman and the CRC for that ROM are written into that file.

-listxml / -lx [<pattern>…]

List comprehensive details for all of the supported systems and devices in XML format. The output is quite long, so it is usually better to redirect this into a file. By default all systems are listed; however, you can limit this list by specifying one or more patterns after the -listxml verb.

This XML output is typically imported into other tools (like graphical front-ends and ROM managers), or processed with scripts query detailed information.

-listfull / -ll [<pattern>…]

Displays a list of system driver names and descriptions. By default all systems and devices are listed; however, you can limit this list by specifying one or more patterns after the -listfull verb.

-listsource / -ls [<pattern>…]

Displays a list of system drivers/devices and the names of the source files where they are defined. Useful for finding which driver a system runs on in order to fix bugs. By default all systems and devices are listed; however, you can limit this list by specifying one or more pattern after the -listsource verb.

-listclones / -lc [<pattern>]

Displays a list of clones. By default all clones are listed; however, you can limit this list by specifying a pattern after the -listsource verb. If a pattern is specified, MAME will list clones of systems that match the pattern, as well as clones that match the pattern themselves.

-listbrothers / -lb [<pattern>]

Displays a list of brothers, i.e. other systems that are defined in the same source file as a system that matches the specified pattern.

-listcrc [<pattern>…]

Displays a full list of CRCs and names of all ROM images referenced by systems and devices matching the specified pattern(s). If no patterns are specified, ROMs referenced by all supported systems and devices will be included.

-listroms / -lr [<pattern>…]

Displays a list of ROM images referenced by supported systems/devices that match the specified pattern(s). If no patterns are specified, the results will include all supported systems and devices.

-listsamples [<pattern>]

Displays a list of samples referenced by the specified pattern of system or device names. If no pattern is specified, the results will be all systems and devices.

-verifyroms [<pattern>]

Checks for invalid or missing ROM images. By default all drivers that have valid ZIP files or directories in the rompath are verified; however, you can limit this list by specifying a pattern after the -verifyroms command.

-verifysamples [<pattern>]

Checks for invalid or missing samples. By default all drivers that have valid ZIP files or directories in the samplepath are verified; however, you can limit this list by specifying a pattern after the -verifyroms command.

-romident [path\to\romstocheck.zip]

Attempts to identify ROM files, if they are known to MAME, in the specified .zip file or directory. This command can be used to try and identify ROM sets taken from unknown boards. On exit, the errorlevel is returned as one of the following:

  • 0: means all files were identified
  • 7: means all files were identified except for 1 or more “non-ROM” files
  • 8: means some files were identified
  • 9: means no files were identified

-listdevices / -ld [<pattern>]

Displays a list of all devices known to be hooked up to a system. The “:” is considered the system itself with the devices list being attached to give the user a better understanding of what the emulation is using.

If slots are populated with devices, any additional slots those devices provide will be visible with -listdevices as well. For instance, installing a floppy controller into a PC will expose the disk drive slots.

-listslots / -lslot [<pattern>]

Show available slots and options for each slot (if available). Primarily used for MAME to allow control over internal plug-in cards, much like PCs needing video, sound and other expansion cards.

If slots are populated with devices, any additional slots those devices provide will be visible with -listslots as well. For instance, installing a floppy controller into a PC will expose the disk drive slots.

The slot name (e.g. ctrl1) can be used from the command line (-ctrl1 in this case)

-listmedia / -lm [<pattern>]

List available media that the chosen system allows to be used. This includes media types (cartridge, cassette, diskette and more) as well as common file extensions which are supported.

-listsoftware / -lsoft [<pattern>]

Posts to screen all software lists which can be used by the entered pattern or system. Note that this is simply a copy/paste of the .XML file which reside in the HASH folder which are allowed to be used.

-verifysoftware / -vsoft [<pattern>]

Checks for invalid or missing ROM images in your software lists. By default all drivers that have valid ZIP files or directories in the rompath are verified; however, you can limit this list by specifying a specific driver name or pattern after the -verifysoftware command.

-getsoftlist / -glist [<pattern>]

Posts to screen a specific software list which matches with the system name provided.

-verifysoftlist / -vlist [softwarelistname]

Checks a specified software list for missing ROM images if files exist for issued softwarelistname. By default, all drivers that have valid ZIP files or directories in the rompath are verified; however, you can limit this list by specifying a specific softwarelistname (without .XML) after the -verifysoftlist command.

OSD-related Options

-uimodekey [keystring]

Key used to enable/disable MAME keyboard controls when the emulated system has keyboard inputs. The default setting is Forward Delete on macOS or SCRLOCK on other operating systems (including Windows and Linux). Use FN-Delete on Macintosh computers with notebook/compact keyboards.

-uifontprovider

Chooses provider for UI font rendering.On Windows, you can choose from: windwritenone or auto.On macOS, you can choose from: osxnone or auto.On other platforms, you can choose from: sdlnone or auto.
Default setting is auto.

-keyboardprovider

Chooses how MAME will get keyboard input.On Windows, you can choose from: autorawinputdinputwin32, or noneOn SDL, you can choose from: autosdlnone
The default is auto.
On Windows, auto will try rawinput with fallback to dinput.On SDL, auto will default to sdl.

-mouseprovider

Chooses how MAME will get mouse input.On Windows, you can choose from: autorawinputdinputwin32, or noneOn SDL, you can choose from: autosdlnone
The default is auto.
On Windows, auto will try rawinput with fallback to dinput.On SDL, auto will default to sdl.

-lightgunprovider

Chooses how MAME will get light gun input.On Windows, you can choose from: autorawinputwin32, or noneOn SDL, you can choose from: autox11 or none
The default is auto.
On Windows, auto will try rawinput with fallback to win32, or none if it doesn’t find any.On SDL/Linux, auto will default to x11, or none if it doesn’t find any.On other SDL, auto will default to none.

-joystickprovider

Chooses how MAME will get joystick input.On Windows, you can choose from: auto, ``winhybriddinputxinput, or noneOn SDL, you can choose from: autosdlnone
The default is auto.
On Windows, auto will default to dinput.
Note that Microsoft XBox 360 and XBox One controllers connected to Windows will work best with winhybrid or xinput. The winhybrid option supports a mix of DirectInput and XInput controllers at the same time.On SDL, auto will default to sdl.

OSD CLI Options

-listmidi

Create a list of available MIDI I/O devices for use with emulation.

-listnetwork

Create a list of available Network Adapters for use with emulation.

OSD Output Options

-output

Chooses how MAME will handle processing of output notifiers.

You can choose from: autononeconsole or network

Note that network port is fixed at 8000.

Configuration Options

-[no]readconfig / -[no]rc

Enables or disables the reading of the config files. When enabled (which is the default), MAME reads the following config files in order:

  • mame.ini
  • debug.ini (if the debugger is enabled)
  • source/<driver>.ini (based on the source filename of the driver)
  • vertical.ini (for systems with vertical monitor orientation)
  • horizont.ini (for systems with horizontal monitor orientation)
  • arcade.ini (for systems in source added with GAME() macro)
  • console.ini (for systems in source added with CONS() macro)
  • computer.ini (for systems in source added with COMP() macro)
  • othersys.ini (for systems in source added with SYST() macro)
  • vector.ini (for vector systems only)
  • <parent>.ini (for clones only, may be called recursively)
  • <systemname>.ini

(See Order of Config Loading for further details)

The settings in the later INIs override those in the earlier INIs. So, for example, if you wanted to disable overlay effects in the vector systems, you can create a vector.ini with line effect none in it, and it will override whatever effect value you have in your mame.ini.

The default is ON (-readconfig).

Core Search Path Options

-homepath <path>

Specifies a path for Lua plugins to store data.

The default is . (that is, in the current working directory).

-rompath / -rp / -biospath / -bp <path>

Specifies one or more paths within which to find ROM or disk images. Multiple paths can be specified by separating them with semicolons.

The default is roms (that is, a directory roms in the current working directory).

-hashpath / -hash_directory / -hash <path>

Specifies one or more paths within which to find software definition files. Multiple paths can be specified by separating them with semicolons.

The default is hash (that is, a directory hash in the current working directory).

-samplepath / -sp <path>

Specifies one or more paths within which to find audio sample files. Multiple paths can be specified by separating them with semicolons.

The default is samples (that is, a directory samples in the current working directory).

-artpath <path> <path>

Specifies one or more paths within which to find external layout and artwork files. Multiple paths can be specified by separating them with semicolons.

The default is artwork (that is, a directory artwork in the current working directory).

-ctrlrpath <path>

Specifies one or more paths within which to find default input configuration files. Multiple paths can be specified by separating them with semicolons.

The default is ctrlr (that is, a directory ctrlr in the current working directory).

-inipath <path>

Specifies one or more paths within which to find INI files. Multiple paths can be specified by separating them with semicolons.

On Windows, the default is .;ini;ini/presets (that is, search in the current directory first, then in the directory ini in the current working directory, and finally the directory presets inside that directory).

On macOS, the default is $HOME/Library/Application Support/mame;$HOME/.mame;.;ini (that is, search the mame folder inside the current user’s Application Support folder, followed by the .mame folder in the current user’s home directory, then the current working directory, and finally the directory ini in the current working directory).

On other platforms (including Linux), the default is $HOME/.mame;.;ini (that is search the .mame directory in the current user’s home directory, followed by the current working directory, and finally the directory ini in the current working directory).

-fontpath <path>

Specifies one or more paths within which to find BDF (Adobe Glyph Bitmap Distribution Format) font files. Multiple paths can be specified by separating them with semicolons.

The default is . (that is, search in the current working directory).

-cheatpath <path>

Specifies one or more paths within which to find XML cheat files. Multiple paths can be specified by separating them with semicolons.

The default is cheat (that is, a folder called cheat located in the current working directory).

-crosshairpath <path>

Specifies one or more paths within which to find crosshair image files. Multiple paths can be specified by separating them with semicolons.

The default is crsshair (that is, a directory crsshair in the current working directory).

-pluginspath <path>

Specifies one or more paths within which to find Lua plugins for MAME.

The default is plugins (that is, a directory plugins in the current working directory).

-languagepath <path>

Specifies one or more paths within which to find language files for localized UI text.

The default is language (that is, a directory language in the current working directory).

-swpath <path>

Specifies the default path from which to load loose software image files.

The default is sofware (that is, a directory software in the current working directory).

Core Output Directory Options

-cfg_directory <path>

Specifies the directory where configuration files are stored. Configuration files are read when starting MAME or when starting an emulated machine, and written on exit. Configuration files preserve settings including input assignment, DIP switch settings, bookkeeping statistics, and debugger window arrangement.

The default is cfg (that is, a directory cfg in the current working directory). If this directory does not exist, it will be created automatically.

-nvram_directory <path>

Specifies the directory where NVRAM files are stored. NVRAM files store the contents of EEPROM, non-volatile RAM (NVRAM), and other programmable devices for systems that used this type of hardware. This data is read when starting an emulated machine and written on exit.

The default is nvram (that is, a directory nvram in the current working directory)). If this directory does not exist, it will be created automatically.

-input_directory <path>

Specifies the directory where input recording files are stored. Input recordings are created using the -record option and played back using the -playback option.

The default is inp (that is, a directory inp in the current working directory). If this directory does not exist, it will be created automatically.

-state_directory <path>

Specifies the directory where save state files are stored. Save state files are read and written either upon user request, or when using the -autosave option.

The default is sta (that is, a directory sta in the current working directory). If this directory does not exist, it will be created automatically.

-snapshot_directory <path>

Specifies the directory where screen snapshots and video recordings are stored when requested by the user.

The default is snap (that is, a directory snap in the current working directory). If this directory does not exist, it will be created automatically.

-diff_directory <path>

Specifies the directory where hard drive difference files are stored. Hard drive difference files store data that is written back to an emulated hard disk, in order to preserve the original image file. The difference files are created when starting an emulated system with a compressed hard disk image.

The default is diff (that is, a directory diff in the current working directory). If this directory does not exist, it will be created automatically.

-comment_directory <path>

Specifies a directory where debugger comment files are stored. Debugger comment files are written by the debugger when comments are added to the disassembly for a system.

The default is comments (that is, a directory comments in the current working directory). If this directory does not exist, it will be created automatically.

Core State/Playback Options

-[no]rewind

When enabled and emulation is paused, automatically creates a save state in memory every time a frame is advanced. Rewind save states can then be loaded consecutively by pressing the rewind single step shortcut key (Left Shift + Tilde by default).

The default rewind value is OFF (-norewind).

If debugger is in a ‘break’ state, a save state is instead created every time step in, step over, or step out occurs. In that mode, rewind save states can be loaded by executing the debugger rewind (or rw) command.

-rewind_capacity <value>

Sets the rewind capacity value, in megabytes. It is the total amount of memory rewind savestates can occupy. When capacity is hit, old savestates get erased as new ones are captured. Setting capacity lower than the current savestate size disables rewind. Values below 0 are automatically clamped to 0.

-state <slot>

Immediately after starting the specified system, will cause the save state in the specified <slot> to be loaded.

-[no]autosave

When enabled, automatically creates a save state file when exiting MAME and automatically attempts to reload it when later starting MAME with the same system. This only works for systems that have explicitly enabled save state support in their driver.

The default is OFF (-noautosave).

-playback / -pb <filename>

Specifies a file from which to play back a series of inputs. This feature does not work reliably for all systems, but can be used to watch a previously recorded game session from start to finish. In order to make things consistent, you should only record and playback with all configuration (.cfg), NVRAM (.nv), and memory card files deleted.

The default is NULL (no playback).

-[no]exit_after_playback

When used in conjunction with the -playback option, MAME will exit after playing back the input file. By default, MAME continues to run the emulated system after playback completes.

The default is OFF (-noexit_after_playback).

-record / -rec <filename>

Specifies a file to record all input from a session. This can be used to record a session for later playback. This feature does not work reliably for all systems, but can be used to watch a previously recorded session from start to finish. In order to make things consistent, you should only record and playback with all configuration (.cfg), NVRAM (.nv), and memory card files deleted.

The default is NULL (no recording).

-record_timecode

Tells MAME to create a timecode file. It contains a line with elapsed times on each press of timecode shortcut key (default is F12). This option works only when recording mode is enabled (-record option). The timecode file is saved in the inp folder.

By default, no timecode file is saved.

-mngwrite <filename>

Writes each video frame to the given <filename> in MNG format, producing an animation of the session. Note that -mngwrite only writes video frames; it does not save any audio data. Either use -wavwrite to record audio and combine the audio and video tracks using video editing software, or use -aviwrite to record audio and video to a single file.

The default is NULL (no recording).

-aviwrite <filename>

Stream video and sound data to the given <filename> in uncompressed AVI format, producing an animation of the session complete with sound. Note that the AVI format does not changes to resolution or frame rate, uncompressed video consumes a lot of disk space, and recording uncompressed video in realtime requires a fast disk. It may be more practical to record an emulation session using -record then make a video of it with -aviwrite in combination with -playback and -exit_after_playback options.

The default is NULL (no recording).

-wavwrite <filename>

Writes the final mixer output to the given <filename> in WAV format, producing an audio recording of the session.

The default is NULL (no recording).

-snapname <name>

Describes how MAME should name files for snapshots. <name> is a string that provides a template that is used to generate a filename.

Three simple substitutions are provided: the / character represents the path separator on any target platform (even Windows); the string %g represents the driver name of the current system; and the string %i represents an incrementing index. If %i is omitted, then each snapshot taken will overwrite the previous one; otherwise, MAME will find the next empty value for %i and use that for a filename.

The default is %g/%i, which creates a separate folder for each system, and names the snapshots under it starting with 0000 and increasing from there.

In addition to the above, for drivers using different media, like carts or floppy disks, you can also use the %d_[media] indicator. Replace [media] with the media switch you want to use.

A few examples:

If you use mame robby -snapname foo/%g%i snapshots will be saved as snaps\\foo\\robby0000.png , snaps\\foo\\robby0001.png and so on.

If you use mame nes -cart robby -snapname %g/%d_cart snapshots will be saved as snaps\\nes\\robby.png.

If you use mame c64 -flop1 robby -snapname %g/%d_flop1/%i snapshots will be saved as snaps\\c64\\robby\\0000.png.

-snapsize <width>x<height>

Hard-codes the size for snapshots and movie recording. By default, MAME will create snapshots at the system’s current resolution in raw pixels, and will create movies at the system’s starting resolution in raw pixels. If you specify this option, then MAME will create both snapshots and movies at the size specified, and will bilinear filter the result. Note that this size does not automatically rotate if the system is vertically oriented.

The default is auto.

-snapview <viewname>

Specifies the view to use when rendering snapshots and movies.

By default, both use a special ‘internal’ view, which renders a separate snapshot per screen or renders movies only of the first screen. By specifying this option, you can override this default behavior and select a single view that will apply to all snapshots and movies. Note that <viewname> does not need to be a perfect match; rather, it will select the first view whose name matches all the characters specified by <viewname>.

For example, -snapview native will match the “Native (15:14)” view even though it is not a perfect match. <viewname> can also be ‘auto’, which selects the first view with all screens present.

The default value is internal.

-[no]snapbilinear

Specify if the snapshot or movie should have bilinear filtering applied. Shutting this off can improve performance while recording video to a file.

The default is ON (-snapbilinear).

-statename <name>

Describes how MAME should store save state files, relative to the state_directory path. <name> is a string that provides a template that is used to generate a relative path.

Two simple substitutions are provided: the / character represents the path separator on any target platform (even Windows); the string %g represents the driver name of the current system.

The default is %g, which creates a separate folder for each system.

In addition to the above, for drivers using different media, like carts or floppy disks, you can also use the %d_[media] indicator. Replace [media] with the media switch you want to use.

A few examples:

If you use mame robby -statename foo/%g save states will be stored inside sta\\foo\\robby\\.

If you use mame nes -cart robby -statename %g/%d_cart save states will be stored inside sta\\nes\\robby\\.

If you use mame c64 -flop1 robby -statename %g/%d_flop1 save states will be stored inside ‘sta\c64\robby\’.

-[no]burnin

Tracks brightness of the screen during play and at the end of emulation generates a PNG that can be used to simulate burn-in effects on other systems. The resulting PNG is created such that the least used-areas of the screen are fully white (since burned-in areas are darker, all other areas of the screen must be lightened a touch).

The intention is that this PNG can be loaded via an artwork file with a low alpha (e.g, 0.1-0.2 seems to work well) and blended over the entire screen.

The PNG files are saved in the snap directory under the <systemname>/burnin-<screen.name>.png.

The default is OFF (-noburnin).

Core Performance Options

-[no]autoframeskip / -[no]afs

Dynamically adjust the frameskip level while you’re running the system to maintain full speed. Turning this on overrides the -frameskip setting described below.

This is off by default (-noautoframeskip).

-frameskip / -fs <level>

Specifies the frameskip value. This is the number of frames out of every 12 to drop when running. For example, if you specify -frameskip 2, MAME will render and display 10 out of every 12 emulated frames. By skipping some frames, you may be able to get full speed emulation for a system that would otherwise be too demanding for your computer.

The default value is -frameskip 0, which skips no frames.

-seconds_to_run / -str <seconds>

This option tells MAME to automatically stop emulation after a fixed number of seconds of emulated time have elapsed. This may be useful for benchmarking and automated testing. By combining this with a fixed set of other command line options, you can set up a consistent environment for benchmarking MAME’s emulation performance. In addition, upon exit, the -str option will write a screenshot called final.png to the system’s snapshot directory.

-[no]throttle

Enable or disable thottling emulation speed. When throttling is enabled, MAME limits emulation speed to so the emulated system will not run faster than the original hardware. When throttling is disabled, MAME runs the emulation as fast as possible. Depending on your settings and the characteristics of the emulated system, performance may be limited by your CPU, graphics card, or even memory performance.

The default is to enable throttling (-throttle).

-[no]sleep

When enabled along with -throttle, MAME will yield the CPU when limiting emulation speed. This allows other programs to use CPU time, assuming the main emulation thread isn’t completely utilising a CPU core. This option can potentially cause hiccups in performance if other demanding programs are running.

The default is on (-sleep).

-speed <factor>

Changes the way MAME throttles the emulation so that it runs at some multiple of the system’s original speed. A <factor> of 1.0 means to run the system at its normal speed, a <factor> of 0.5 means run at half speed, and a <factor> of 2.0 means run at double speed. Note that changing this value affects sound playback as well, which will scale in pitch accordingly. The internal precision of the fraction is two decimal places, so a <factor> of 1.002 is rounded to 1.00.

The default is 1.0 (normal speed).

-[no]refreshspeed / -[no]rs

Allows MAME to adjust the emulation speed so that the refresh rate of the first emulated screen does not exceed the slowest refresh rate for any targeted monitors in your system. Thus, if you have a 60Hz monitor and run a system that is designed to run at 60.6Hz, MAME will reduce the emulation speed to 99% in order to prevent sound hiccups or other undesirable side effects of running at a slower refresh rate.

The default is off (-norefreshspeed).

-numprocessors / -np auto|<value>

Specify the number of threads to use for work queues. Specifying auto will use the value reported by the system or environment variable OSDPROCESSORS. This value is internally limited to four times the number of processors reported by the system.

The default is auto.

-bench <n>

Benchmark for <n> emulated seconds. This is equivalent to the following options:

-str <n> -video none -sound none -nothrottle

-lowlatency

This tells MAME to draw a new frame before throttling to reduce input latency. This is particularly effective with VRR (Variable Refresh Rate) displays.

This may cause frame pacing issues in the form of jitter with some systems (especially newer 3D-based systems or systems that run software akin to an operating system), so the default is off (-nolowlatency).

Core Rotation Options

-[no]rotate

Rotate the system to match its normal state (horizontal/vertical). This ensures that both vertically and horizontally oriented systems show up correctly without the need to rotate your monitor. If you want to keep the system displaying ‘raw’ on the screen the way it would have in the arcade, turn this option OFF.

The default is ON (-rotate).

-[no]ror

-[no]rol

Rotate the system screen to the right (clockwise) or left (counter-clockwise) relative to either its normal state (if -rotate is specified) or its native state (if -norotate is specified).

The default for both of these options is OFF (-noror -norol).

-[no]autoror

-[no]autorol

These options are designed for use with pivoting screens that only pivot in a single direction. If your screen only pivots clockwise, use -autorol to ensure that the system will fill the screen either horizontally or vertically in one of the directions you can handle. If your screen only pivots counter-clockwise, use -autoror.

-[no]flipx

-[no]flipy

Flip (mirror) the system screen either horizontally (-flipx) or vertically (-flipy). The flips are applied after the -rotate and -ror/-rol options are applied.

The default for both of these options is OFF (-noflipx -noflipy).

Core Video Options

-video <bgfx|gdi|d3d|opengl|soft|accel|none>

Specifies which video subsystem to use for drawing. Options here depend on the operating system and whether this is an SDL-compiled version of MAME.

Generally Available:Using bgfx specifies the new hardware accelerated renderer.
Using opengl tells MAME to render video using OpenGL acceleration.
Using none displays no windows and does no drawing. This is primarily present for doing CPU benchmarks without the overhead of the video system.

On Windows:Using gdi tells MAME to render video using older standard Windows graphics drawing calls. This is the slowest but most compatible option on older versions of Windows.
Using d3d tells MAME to use Direct3D for rendering. This produces the better quality output than gdi and enables additional rendering options. It is recommended if you have a semi-recent (2002+) video card or onboard Intel video of the HD3000 line or better.

On other platforms (including SDL on Windows):Using accel tells MAME to render video using SDL’s 2D acceleration if possible.
Using soft uses software rendering for video output. This isn’t as fast or as nice as OpenGL but will work on any platform.

Defaults:The default on Windows is d3d.
The default for Mac OS X is opengl because OS X is guaranteed to have a compliant OpenGL stack.
The default on all other systems is soft.

-numscreens <count>

Tells MAME how many output windows to create. For most systems, a single output window is all you need, but some systems originally used multipl screens (e.g. Darius and PlayChoice-10 arcade machines). Each screen (up to 4) has its own independent settings for physical monitor, aspect ratio, resolution, and view, which can be set using the options below.

The default is 1.

-[no]window / -[no]w

Run MAME in either a window or full screen.

The default is OFF (-nowindow).

-[no]maximize / -[no]max

Controls initial window size in windowed mode. If it is set on, the window will initially be set to the maximum supported size when you start MAME. If it is turned off, the window will start out at the closest possible size to the original size of the display; it will scale on only one axis where non-square pixels are used. This option only has an effect when the -window option is used.

The default is ON (-maximize).

-[no]keepaspect / -[no]ka

When enabled, MAME preserves the correct aspect ratio for the emulated system’s screen(s). This is most often 4:3 or 3:4 for CRT monitors (depending on the orientation), though many other aspect ratios have been used, such as 3:2 (Nintendo Game Boy), 5:4 (some workstations), and various other ratios. If the emulated screen and/or artwork does not fill MAME’s screen or Window, the image will be centred and black bars will be added as necessary to fill unused space (either above/below or to the left and right).

When this option is disabled, the emulated screen and/or artwork will be stretched to fill MAME’s screen or window. The image will be distorted by non-proportional scaling if the aspect ratio does not match. This is very pronounced when the emulated system uses a vertically-oriented screen and MAME stretches the image to fill a horizontally-oriented screen.

On Windows, when this option is enabled and MAME is running in a window (not full screen), the aspect ratio will be maintained when you resize the window unless you hold the Control (or Ctrl) key on your keyboard. The window size will not be restricted when this option is disabled.

The default is ON (-keepaspect).

The MAME team strongly recommends leaving this option enabled. Stretching systems beyond their original aspect ratio will mangle the appearance of the system in ways that no filtering or shaders can repair.

-[no]waitvsync

Waits for the refresh period on your computer’s monitor to finish before starting to draw video to your screen. If this option is off, MAME will just draw to the screen as a frame is ready, even if in the middle of a refresh cycle. This can cause “tearing” artifacts, where the top portion of the screen is out of sync with the bottom portion.

The effect of turning -waitvsync on differs a bit between combinations of different operating systems and video drivers.

On Windows, -waitvsync will block until video blanking before allowing MAME to draw the next frame, limiting the emulated machine’s framerate to that of the host display. Note that this option does not work with -video gdi mode in Windows.

On macOS, -waitvsync does not block; instead the most recent completely drawn frame will be displayed at vblank. This means that if an emulated system has a higher framerate than your host display, emulated frames will be dropped periodically resulting in motion judder.

On Windows, you should only need to turn this on in windowed mode. In full screen mode, it is only needed if -triplebuffer does not remove the tearing, in which case you should use -notriplebuffer -waitvsync.

Note that SDL-based MAME support for this option depends entirely on your operating system and video drivers; in general it will not work in windowed mode so -video opengl and fullscreen give the greatest chance of success with SDL builds of MAME.

The default is OFF (-nowaitvsync).

-[no]syncrefresh

Enables speed throttling only to the refresh of your monitor. This means that the system’s actual refresh rate is ignored; however, the sound code still attempts to keep up with the system’s original refresh rate, so you may encounter sound problems.

This option is intended mainly for those who have tweaked their video card’s settings to provide carefully matched refresh rate options. Note that this option does not work with -video gdi mode.

The default is OFF (-nosyncrefresh).

-prescale <amount>

Controls the size of the screen images when they are passed off to the graphics system for scaling. At the minimum setting of 1, the screen is rendered at its original resolution before being scaled. At higher settings, the screen is expanded in both axes by a factor of <amount> using nearest-neighbor sampling before applying filters or shaders. With -video d3d, this produces a less blurry image at the expense of speed.

The default is 1.

This is supported with all video output types (bgfxd3d, etc) on Windows and is ONLY supported with OpenGL on other platforms.

-[no]filter / -[no]d3dfilter / -[no]flt

Enable bilinear filtering on the system screen graphics. When disabled, point filtering is applied, which is crisper but leads to scaling artifacts. If you don’t like the filtered look, you are probably better off increasing the -prescale value rather than turning off filtering altogether.

The default is ON (-filter).

This is supported with OpenGL and D3D video on Windows and is ONLY supported with OpenGL on other platforms.

Use bgfx_screen_chains in your INI file(s) to adjust filtering with the BGFX video system.

-[no]unevenstretch

Allow non-integer scaling factors allowing for great window sizing flexability.

The default is ON. (-unevenstretch)

Core Full Screen Options

-[no]switchres

Enables resolution switching. This option is required for the -resolution* options to switch resolutions in full screen mode.

On modern video cards, there is little reason to switch resolutions unless you are trying to achieve the “exact” pixel resolutions of the original systems, which requires significant tweaking. This option is also useful on LCD displays, since they run with a fixed resolution and switching resolutions on them is just silly. This option does not work with -video gdi.

The default is OFF (-noswitchres).

Core Per-Window Options

NOTE: Multiple Screens may fail to work correctly on some Mac machines as of right now.

-screen <display>

-screen0 <display>

-screen1 <display>

-screen2 <display>

-screen3 <display>

Specifies which physical monitor on your system you wish to have each window use by default. In order to use multiple windows, you must have increased the value of the -numscreens option. The name of each display in your system can be determined by running MAME with the -verbose option. The display names are typically in the format of: \\\\.\\DISPLAYn, where ‘n’ is a number from 1 to the number of connected monitors.

The default value for these options is auto, which means that the first window is placed on the first display, the second window on the second display, etc.

The -screen0-screen1-screen2-screen3 parameters apply to the specific window. The -screen parameter applies to all windows. The window-specific options override values from the all window option.

-aspect <width:height> / -screen_aspect <num:den>

-aspect0 <width:height>

-aspect1 <width:height>

-aspect2 <width:height>

-aspect3 <width:height>

Specifies the physical aspect ratio of the physical monitor for each window. In order to use multiple windows, you must have increased the value of the -numscreens option. The physical aspect ratio can be determined by measuring the width and height of the visible screen image and specifying them separated by a colon.

The default value for these options is auto, which means that MAME assumes the aspect ratio is proportional to the number of pixels in the desktop video mode for each monitor.

The -aspect0-aspect1-aspect2-aspect3 parameters apply to the specific window. The -aspect parameter applies to all windows. The window-specific options override values from the all window option.

-resolution <widthxheight[@refresh]> / -r <widthxheight[@refresh]>

-resolution0 <widthxheight[@refresh]> / -r0 <widthxheight[@refresh]>

-resolution1 <widthxheight[@refresh]> / -r1 <widthxheight[@refresh]>

-resolution2 <widthxheight[@refresh]> / -r2 <widthxheight[@refresh]>

-resolution3 <widthxheight[@refresh]> / -r3 <widthxheight[@refresh]>

Specifies an exact resolution to run in. In full screen mode, MAME will try to use the specific resolution you request. The width and height are required; the refresh rate is optional. If omitted or set to 0, MAME will determine the mode automatically. For example, -resolution 640×480 will force 640×480 resolution, but MAME is free to choose the refresh rate. Similarly, -resolution 0x0@60 will force a 60Hz refresh rate, but allows MAME to choose the resolution. The string auto is also supported, and is equivalent to 0x0@0.

In window mode, this resolution is used as a maximum size for the window. This option requires the -switchres option as well in order to actually enable resolution switching with -video d3d.

The default value for these options is auto.

The -resolution0-resolution1-resolution2-resolution3 parameters apply to the specific window. The -resolution parameter applies to all windows. The window-specific options override values from the all window option.

-view <viewname>

-view0 <viewname>

-view1 <viewname>

-view2 <viewname>

-view3 <viewname>

Specifies the initial view setting for each window. The <viewname> does not need to be a perfect match; rather, it will select the first view whose name matches all the characters specified by <viewname>. For example, -view native will match the “Native (15:14)” view even though it is not a perfect match. The value auto is also supported, and requests that MAME perform a default selection.

The default value for these options is auto.

The -view0-view1-view2-view3 parameters apply to the specific window. The -view parameter applies to all windows. The window-specific options override values from the all window option.

Core Artwork Options

-[no]artwork_crop / -[no]artcrop

Enable cropping of artwork to the system screen area only. This means that vertically oriented systems running full screen can display their artwork to the left and right sides of the screen. This option can also be controlled via the Video Options menu in the user interface.

The default is OFF -noartwork_crop.

-fallback_artwork

Specifies fallback artwork if no external artwork or internal driver layout is defined.

-override_artwork

Specifies override artwork for external artwork and internal driver layout.

Core Screen Options

-brightness <value>

Controls the default brightness, or black level, of the system screens. This option does not affect the artwork or other parts of the display. Using the MAME UI, you can individually set the brightness for each system screen; this option controls the initial value for all visible system screens. The standard value is 1.0. Selecting lower values (down to 0.1) will produce a darkened display, while selecting higher values (up to 2.0) will give a brighter display.

The default is 1.0.

-contrast <value>

Controls the contrast, or white level, of the system screens. This option does not affect the artwork or other parts of the display. Using the MAME UI, you can individually set the contrast for each system screen; this option controls the initial value for all visible system screens. The standard value is 1.0. Selecting lower values (down to 0.1) will produce a dimmer display, while selecting higher values (up to 2.0) will give a more saturated display.

The default is 1.0.

-gamma <value>

Controls the gamma, which produces a potentially nonlinear black to white ramp, for the system screens. This option does not affect the artwork or other parts of the display. Using the MAME UI, you can individually set the gamma for each system screen; this option controls the initial value for all visible system screens. The standard value is 1.0, which gives a linear ramp from black to white. Selecting lower values (down to 0.1) will increase the nonlinearity toward black, while selecting higher values (up to 3.0) will push the nonlinearity toward white.

The default is 1.0.

-pause_brightness <value>

This controls the brightness level when MAME is paused.

The default value is 0.65.

-effect <filename>

Specifies a single PNG file that is used as an overlay over any system screens in the video display. This PNG file is assumed to live in the root of one of the artpath directories. The pattern in the PNG file is repeated both horizontally and vertically to cover the entire system screen areas (but not any external artwork), and is rendered at the target resolution of the system image.

For -video gdi and -video d3d modes, this means that one pixel in the PNG will map to one pixel on your output display. The RGB values of each pixel in the PNG are multiplied against the RGB values of the target screen.

The default is none, meaning no effect.

Core Vector Options

-beam_width_min <width>

Sets the vector beam minimum width.

-beam_width_max <width>

Sets the vector beam maximum width.

-beam_intensity_weight <weight>

Sets the vector beam intensity weight.

-flicker <value>

Simulates a vector “flicker” effect, similar to a vector monitor that needs adjustment. This option requires a float argument in the range of 0.00 – 100.00 (0=none, 100=maximum).

The default is 0.

Core Video OpenGL Debugging Options

These options are for compatibility in -video opengl. If you report rendering artifacts you may be asked to try messing with them by the devs, but normally they should be left at their defaults which results in the best possible video performance.

-[no]gl_forcepow2texture

Always use only power-of-2 sized textures.

The default is OFF. (-nogl_forcepow2texture)

-[no]gl_notexturerect

Don’t use OpenGL GL_ARB_texture_rectangle.

The default is ON. (-gl_notexturerect)

-[no]gl_vbo

Enable OpenGL VBO (Vertex Buffer Objects), if available.

The default is ON. (-gl_vbo)

-[no]gl_pbo

Enable OpenGL PBO (Pixel Buffer Objects), if available (default on)

The default is ON. (-gl_pbo)

Core Video OpenGL GLSL Options

-gl_glsl

Enable OpenGL GLSL, if available.

The default is OFF.

-gl_glsl_filter

Use OpenGL GLSL shader-based filtering instead of fixed function pipeline-based filtering.

0-plain, 1-bilinear, 2-bicubic

The default is 1. (-gl_glsl_filter 1)

-glsl_shader_mame0

-glsl_shader_mame1

-glsl_shader_mame9

Custom OpenGL GLSL shader set MAME bitmap in the provided slot (0-9); one can be applied to each slot.

[todo: better details on usage at some point. See http://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=100988#Post100988 ]

-glsl_shader_screen0

-glsl_shader_screen1

-glsl_shader_screen9

Custom OpenGL GLSL shader screen bitmap in the provided slot (0-9).

[todo: better details on usage at some point. See http://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=100988#Post100988 ]

-gl_glsl_vid_attr

Enable OpenGL GLSL handling of brightness and contrast. Better RGB system performance.

Default is on.

Core Sound Options

-samplerate <value> / -sr <value>

Sets the audio sample rate. Smaller values (e.g. 11025) cause lower audio quality but faster emulation speed. Higher values (e.g. 48000) cause higher audio quality but slower emulation speed.

The default is 48000.

-[no]samples

Use samples if available.

The default is ON (-samples).

-volume / -vol <value>

Sets the startup volume. It can later be changed with the user interface (see Keys section). The volume is an attenuation in dB: e.g., “-volume -12” will start with -12dB attenuation.

The default is 0.

-sound <“dsound“|“coreaudio“|“sdl“|“xaudio2“|“portaudio“|“none“>

Specifies which sound subsystem to use. Selecting none disables sound output altogether (sound hardware is still emulated).On Windows, dsoundxaudio2portaudio and none are available.On macOS, coreaudiosdlportaudio and none are available.On other operating systems, sdlportaudio and none are available. (Special build options allow sdl to be used on Windows, or portaudio to be disabled.)
The default is dsound on Windows. On Mac, coreaudio is the default. On all other platforms, sdl is the default.

On Windows and Linux, portaudio is likely to give the lowest possible latency, while Mac users will find coreaudio provides the best results.

When using the sdl sound subsystem, the audio API to use may be selected by setting the SDL_AUDIODRIVER environment variable. Available audio APIs depend on the operating system. On Windows, it may be necessary to set SDL_AUDIODRIVER=directsound if no sound output is produced by default.

-audio_latency <value>

The exact behavior depends on the selected audio output module. Smaller values provide less audio delay while requiring better system performance. Higher values increase audio delay but may help avoid buffer under-runs and audio interruptions.

The default is 1.

Core Input Options

-[no]coin_lockout / -[no]coinlock

Enables simulation of the “coin lockout” feature that is implemented on a number of arcade game PCBs. It was up to the operator whether or not the coin lockout outputs were actually connected to the coin mechanisms. If this feature is enabled, then attempts to enter a coin while the lockout is active will fail and will display a popup message in the user interface (in debug mode). If this feature is disabled, the coin lockout signal will be ignored.

The default is ON (-coin_lockout).

-ctrlr <controller>

Enables support for special controllers. Configuration files are loaded from the ctrlrpath. They are in the same format as the .cfg files that are saved, but only control configuration data is read from the file.

The default is NULL (no controller file).

-[no]mouse

Controls whether or not MAME makes use of mouse controllers. When this is enabled, you will likely be unable to use your mouse for other purposes until you exit or pause the system.

The default is OFF (-nomouse).

-[no]joystick / -[no]joy

Controls whether or not MAME makes use of joystick/gamepad controllers.

When this is enabled, MAME will ask the system about which controllers are connected.

The default is OFF (-nojoystick).

-[no]lightgun / -[no]gun

Controls whether or not MAME makes use of lightgun controllers. Note that most lightguns map to the mouse, so using -lightgun and -mouse together may produce strange results.

The default is OFF (-nolightgun).

-[no]multikeyboard / -[no]multikey

Determines whether MAME differentiates between multiple keyboards. Some systems may report more than one keyboard; by default, the data from all of these keyboards is combined so that it looks like a single keyboard.

Turning this option on will enable MAME to report keypresses on different keyboards independently.

The default is OFF (-nomultikeyboard).

-[no]multimouse

Determines whether MAME differentiates between multiple mice. Some systems may report more than one mouse device; by default, the data from all of these mice is combined so that it looks like a single mouse. Turning this option on will enable MAME to report mouse movement and button presses on different mice independently.

The default is OFF (-nomultimouse).

-[no]steadykey / -[no]steady

Some systems require two or more buttons to be pressed at exactly the same time to make special moves. Due to limitations in the keyboard hardware, it can be difficult or even impossible to accomplish that using the standard keyboard handling. This option selects a different handling that makes it easier to register simultaneous button presses, but has the disadvantage of making controls less responsive.

The default is OFF (-nosteadykey)

-[no]ui_active

Enable user interface on top of emulated keyboard (if present).

The default is OFF (-noui_active)

-[no]offscreen_reload / -[no]reload

Controls whether or not MAME treats a second button input from a lightgun as a reload signal. In this case, MAME will report the gun’s position as (0,MAX) with the trigger held, which is equivalent to an offscreen reload.

This is only needed for games that required you to shoot offscreen to reload, and then only if your gun does not support off screen reloads.

The default is OFF (-nooffscreen_reload).

-joystick_map <map> / -joymap <map>

Controls how joystick values map to digital joystick controls. MAME accepts all joystick input from the system as analog data. For true analog joysticks, this needs to be mapped down to the usual 4-way or 8-way digital joystick values. To do this, MAME divides the analog range into a 9×9 grid. It then takes the joystick axis position (for X and Y axes only), maps it to this grid, and then looks up a translation from a joystick map. This parameter allows you to specify the map.

The default is auto, which means that a standard 8-way, 4-way, or 4-way diagonal map is selected automatically based on the input port configuration of the current system.

Maps are defined as a string of numbers and characters. Since the grid is 9×9, there are a total of 81 characters necessary to define a complete map. Below is an example map for an 8-way joystick:

777888999777888999777888999444555666444555666444555666111222333111222333111222333Note that the numeric digits correspond to the keyson a numeric keypad. So ‘7’ maps to up+left, ‘4’ mapsto left, ‘5’ maps to neutral, etc. In addition to thenumeric values, you can specify the character ‘s’,which means “sticky”. In this case, the value of themap is the same as it was the last time a non-stickyvalue was read.

To specify the map for this parameter, you can specify a string of rows separated by a ‘.’ (which indicates the end of a row), like so:

-joymap 777888999.777888999.777888999.444555666.444555666.444555666.111222333.111222333.111222333

However, this can be reduced using several shorthands supported by the <map> parameter. If information about a row is missing, then it is assumed that any missing data in columns 5-9 are left/right symmetric with data in columns 0-4; and any missing data in columns 0-4 is assumed to be copies of the previous data. The same logic applies to missing rows, except that up/down symmetry is assumed.

By using these shorthands, the 81 character map can be simply specified by this 11 character string: 7778…4445 (which means we then use -joymap 7778…4445)

Looking at the first row, 7778 is only 4 characters long. The 5th entry can’t use symmetry, so it is assumed to be equal to the previous character ‘8’. The 6th character is left/right symmetric with the 4th character, giving an ‘8’. The 7th character is left/right symmetric with the 3rd character, giving a ‘9’ (which is ‘7’ with left/right flipped). Eventually this gives the full 777888999 string of the row.

The second and third rows are missing, so they are assumed to be identical to the first row. The fourth row decodes similarly to the first row, producing 444555666. The fifth row is missing so it is assumed to be the same as the fourth.

The remaining three rows are also missing, so they are assumed to be the up/down mirrors of the first three rows, giving three final rows of 111222333.

-joystick_deadzone <value> / -joy_deadzone <value> / -jdz <value>

If you play with an analog joystick, the center can drift a little. joystick_deadzone tells how far along an axis you must move before the axis starts to change. This option expects a float in the range of 0.0 to 1.0. Where 0 is the center of the joystick and 1 is the outer limit.

The default is 0.3.

-joystick_saturation <value> / joy_saturation <value> / -jsat <value>

If you play with an analog joystick, the ends can drift a little, and may not match in the +/- directions. joystick_saturation tells how far along an axis movement change will be accepted before it reaches the maximum range. This option expects a float in the range of 0.0 to 1.0, where 0 is the center of the joystick and 1 is the outer limit.

The default is 0.85.

-natural

Allows user to specify whether or not to use a natural keyboard or not. This allows you to start your system in a ‘native’ mode, depending on your region, allowing compatability for non-“QWERTY” style keyboards.

The default is OFF (-nonatural)

In “emulated keyboard” mode (the default mode), MAME translates pressing/releasing host keys/buttons to emulated keystrokes. When you press/release a key/button mapped to an emulated key, MAME presses/releases the emulated key.

In “natural keyboard” mode, MAME attempts to translate characters to keystrokes. The OS translates keystrokes to characters (similarly when you type into a text editor), and MAME attempts to translate these characters to emulated keystrokes.

There are a number of unavoidable limitations in “natural keyboard” mode:

  • The emulated system driver and/or keyboard device or has to support it.
  • The selected keyboard must match the keyboard layout selected in the emulated OS!
  • Keystrokes that don’t produce characters can’t be translated. (e.g. pressing a modifier on its own such as shiftctrl, or alt)
  • Holding a key until the character repeats will cause the emulated key to be pressed repeatedly as opposed to being held down.
  • Dead key sequences are cumbersome to use at best.
  • It won’t work at all if IME edit is involved. (e.g. for Chinese/Japanese/Korean)

-joystick_contradictory

Enable contradictory direction digital joystick input at the same time such as Left and Right or Up and Down at the same time.

The default is OFF (-nojoystick_contradictory)

-coin_impulse [n]

Set coin impulse time based on n (n<0 disable impulse, n==0 obey driver, 0<n set time n).

Default is 0.

Core Input Automatic Enable Options

-paddle_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-adstick_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-pedal_device (none``|``keyboard``|``mouse``|```lightgun``|``joystick)

-dial_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-trackball_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-lightgun_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-positional_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

-mouse_device (none``|``keyboard``|``mouse``|``lightgun``|``joystick)

Each of these options controls autoenabling the mouse, joystick, or lightgun depending on the presence of a particular class of analog control for a particular system. For example, if you specify the option -paddle mouse, then any game that has a paddle control will automatically enable mouse controls just as if you had explicitly specified -mouse.

Note that these controls override the values of -[no]mouse-[no]joystick, etc.

Debugging Options

-[no]verbose / -[no]v

Displays internal diagnostic information. This information is very useful for debugging problems with your configuration. IMPORTANT: when reporting bugs, please run with mame -verbose and include the resulting information.

The default is OFF (-noverbose).

-[no]oslog

Output error.log messages to the system diagnostic output, if one is present.

By default messages are sent to the standard error output (this is typically displayed in the terminal or command prompt window, or saved to a system log file). On Windows, if a debugger is attached (e.g. the Visual Studio debugger or WinDbg), messages will be sent to the debugger instead.

The default is OFF (-nooslog).

-[no]log

Creates a file called error.log which contains all of the internal log messages generated by the MAME core and system drivers. This can be used at the same time as -log to output the log data to both targets as well.

The default is OFF (-nolog).

-[no]debug

Activates the integrated debugger. By default, the debugger is entered by pressing the tilde (~) key during emulation. It is also entered immediately at startup.

The default is OFF (-nodebug).

-debugscript <filename>

Specifies a file that contains a list of debugger commands to execute immediately upon startup.

The default is NULL (no commands).

-[no]update_in_pause

Enables updating of the main screen bitmap while the system is paused. This means that the video update callback will be called repeatedly while the emulation is paused, which can be useful for debugging.

The default is OFF (-noupdate_in_pause).

-watchdog <duration> / -wdog <duration>

Enables an internal watchdog timer that will automatically kill the MAME process if more than <duration> seconds passes without a frame update. Keep in mind that some systems sit for a while during load time without updating the screen, so <duration> should be long enough to cover that.

10-30 seconds on a modern system should be plenty in general.

By default there is no watchdog.

-debugger_font <fontname> / -dfont <fontname>

Specifies the name of the font to use for debugger windows.The Windows default font is Lucida Console.The Mac (Cocoa) default font is system fixed-pitch font default (typically Monaco).The Qt default font is Courier New.

-debugger_font_size <points> / -dfontsize <points>

Specifies the size of the font to use for debugger windows, in points.The Windows default size is 9 points.The Qt default size is 11 points.The Mac (Cocoa) default size is the system default size.

Core Communication Options

-comm_localhost <string>

Local address to bind to. This can be a traditional xxx.xxx.xxx.xxx address or a string containing a resolvable hostname.

The default is value is “0.0.0.0” (which binds to all local IPv4 addresses).

-comm_localport <string>

Local port to bind to. This can be any traditional communications port as an unsigned 16-bit integer (0-65535).

The default value is “15122“.

-comm_remotehost <string>

Remote address to connect to. This can be a traditional xxx.xxx.xxx.xxx address or a string containing a resolvable hostname.

The default is value is “0.0.0.0” (which binds to all local IPv4 addresses).

-comm_remoteport <string>

Remote port to connect to. This can be any traditional communications port as an unsigned 16-bit integer (0-65535).

The default value is “15122“.

-[no]comm_framesync

Synchronize frames between the communications network.

The default is OFF (-nocomm_framesync).

Core Misc Options

-[no]drc

Enable DRC (dynamic recompiler) CPU core if available for maximum speed.

The default is ON (-drc).

-drc_use_c

Force DRC to use the C code backend.

The default is OFF (-nodrc_use_c).

-drc_log_uml

Write DRC UML disassembly log.

The default is OFF (-nodrc_log_uml).

-drc_log_native

Write DRC native disassembly log.

The default is OFF (-nodrc_log_native).

-bios <biosname>

Specifies the specific BIOS to use with the current system, for systems that make use of a BIOS. The -listxml output will list all of the possible BIOS names for a system.

The default is default.

-[no]cheat / -[no]c

Activates the cheat menu with autofire options and other tricks from the cheat database, if present. This also activates additional options on the slider menu for overclocking/underclocking.

Be advised that savestates created with cheats on may not work correctly with this turned off and vice-versa.

The default is OFF (-nocheat).

-[no]skip_gameinfo

Forces MAME to skip displaying the system info screen.

The default is OFF (-noskip_gameinfo).

-uifont <fontname>

Specifies the name of a font file to use for the UI font. If this font cannot be found or cannot be loaded, the system will fall back to its built-in UI font. On some platforms fontname can be a system font name instead of a BDF font file.

The default is default (use the OSD-determined default font).

-ui <type>

Specifies the type of UI to use, either simple or cabinet.

The default is Cabinet (-ui cabinet).

-ramsize [n]

Allows you to change the default RAM size (if supported by driver).

-confirm_quit

Display a Confirm Quit dialog to screen on exit, requiring one extra step to exit MAME.

The default is OFF (-noconfirm_quit).

-ui_mouse

Displays a mouse cursor when using the built-in UI for MAME.

The default is (-noui_mouse).

-language <language>

Specify a localization language found in the languagepath tree.

-[no]nvram_save

Save the NVRAM contents when exiting machine emulation. By turning this off, you can retain your previous NVRAM contents as any current changes made will not be saved. Turning this option off will also unconditionally suppress the saving of .nv files associated with some types of software cartridges.

The default is ON (-nvram_save).

Scripting Options

-autoboot_command “<command>”

Command string to execute after machine boot (in quotes ” “). To issue a quote to the emulation, use “”” in the string. Using \n will issue a create a new line, issuing what was typed prior as a command.

This works only with systems that support natural keyboard mode.

Example: -autoboot_command “load “””$”””,8,1\n”

-autoboot_delay [n]

Timer delay (in seconds) to trigger command execution on autoboot.

-autoboot_script / -script [filename.lua]

File containing scripting to execute after machine boot.

-[no]console

Enables emulator Lua Console window.

The default of OFF (-noconsole).

-plugins

Enable the use of Lua Plugins.

The default is ON (-plugins).

-plugin [plugin shortname]

A list of Lua Plugins to enable, comma separated.

-noplugin [plugin shortname]

A list of Lua Plugins to disable, comma separated.

HTTP Server Options

-[no]http

Enable HTTP server.

The default is OFF (-nohttp).

-http_port [port]

Choose HTTP server port.

The default is 8080.

-http_root [rootfolder]

Choose HTTP server document root.

The default is web.