What you'll need

• Some decently new libTAS release.
• A versioned release of MAME, ideally pre-compiled.
  • For Ubuntu, just grab something from Canonical Launchpad. current stable release is fine unless you need something newer. You only need the mame-data and mame .deb packages, and make sure you get the right build for your architecture (usually it's amd64).
  • There's also this unofficial repository that hosts builds of latest MAME release for several Ubuntu releases, but previous builds get wiped regularly.
• Your game that runs on MAME.
  • MAME ROMs are usually packed into .zip archives, but MAME can launch them from .7z or even a regular folder, as long as its called after the right ROM set.
  • If you want to TAS a version (clone) of the game, you still need its base (parent) ROMs to be there too. Merged ROM sets have everything in the parent package, but MAME User Interface only detects games if they are packaged separately, so you won't be able to run the clone from MAME menus. But you can still launch it from terminal.
  • If your game requires a BIOS (put it in the same folder as your ROM), and there are several compatible BIOS files in your set, you need to select the one you want to use. The easiest way is to do it in MAME menus: Configure Machine in main menu or the Tab hotkey when the game is loaded. You can also specify it via the -bios command-line argument, but to know what the right option is called you need to run mame with your game and -listxml argument, and the biosset name entries in the output will be what you need.

Using with libTAS

1. MAME usually installs itself into /usr/games/mame so use that path for the Game executable field.
2. Command-line options should be yourrom -window -nokeepaspect -skip_gameinfo -nomaximize -nounevenstretch -nonvram_save where yourrom is actually the name of your game's ROM set package. Full list of options MAME supports.
3. If you don't know which folders MAME looks for ROMs in and where to put your ROM, put it anywhere and add -rompath folder/containing/your/rom to Command-line options, with actual path to your ROM, but without the filename.
4. Make sure Runtime -> Prevent writing to disk is enabled, or MAME will dump files onto your disk, messing with game state and movie sync.
5. If you've already launched your game outside libTAS, or if you've launched it in libTAS with Runtime -> Prevent writing to disk disabled, you may have nvram (non-volatile RAM) contents dumped to your disk, which will mess with game state and movie sync. In Ubuntu, go to ~/.mame and delete everything (usually it's cfg, nvram, and .inis).
6. You can skip imperfect emulation warnings that appear before the game starts if there are emulation issues with it, but there's no command-line argument for it.
   • The easiest way to do it is by doing what it asks for: pressing any key to continue, right inside your movie recording.
   • A more elaborate way requires using MAME's UI menu: Configure Options -> Miscellaneous Options -> Skip imperfect emulation warnings, but it also involves launching MAME normally and making it save ui.ini with this setting. Which means whoever will try to sync your movie will have to have that setting enabled as well.

Input keys

• Launch MAME normally.
  • If you're running MAME without a game loaded, use Tab to get to General Settings, and then go to Input Assignments.
  • If you're running it with your game, hit Tab and go to Input Settings -> Input Assignments (this system) or Input Assignments (general). The former is probably more convenient because you don't have to assign keys you won't need for that game.
• Run MAME from libTAS.
  • In order to access its menu you need to disable hotkey binding for Tab in libTAS Input -> Configure mapping menu (bound to Fast-forward by default).

• UI hotkeys can be disabled by going to General Settings -> Input Assignments -> User Interface from the main MAME menu, or to Input Settings -> Input Assignments (general) -> User Interface while running a game.
  Note: don't clear UI Up/Down/Select/Cancel hotkeys if you don't have mouse pointer working in MAME, otherwise you won't be able to navigate through menus.
• Download this file and put it into ~/.mame/cfg. Alternatively, you can put it into any folder and then send that path to MAME via the -cfg_directory command-line argument.

Framerate

• MAME stores framerate as frame duration in attoseconds, but signed 32-bit integers needed for numerator and denominator (according to AVI specification) are too small for all this information, so we have to reduce it. But due to some other complications described in this pull request, we have to reduce it to some arbitrary value that is mostly accurate from a human perspective. At least the value we use here matches MAME's AVI framerate since version 0.254 (and BizHawk since 2.9.1).

MAME replay file

• Disable Runtime -> Prevent writing to disk
• Add -record somefilename.inp to libTAS's Command-line options
• Replay your .ltm movie and stop when needed
• The resulting file will appear in ~/.mame/inp
• Replay it in standalone MAME via -playback somefilename.inp and other arguments of your choice

Movie submissions

• There should be no significant glitches caused by poor emulation (look out for machines marked by MAME as Overall: NOT WORKING or with something Unimplemented).
• Non-arcade machines are only allowed if:
  • TASVideos doesn't have an approved rerecording emulator for that system

• libTAS version
• MAME version (ideally with a link to the release build package)
• Additional MAME configuration steps if they are necessary for your movie.
• Filename and MD5 hash of your ROM set (use md5sum yourgame.zip in a terminal)