# M.U.G.E.N RC EX + alpha

The RC EX + alpha releases were experimental alpha releases of a development branch of the 1.0 RCs containing some BGM- and sound-related changes. The functionality from the EX + alpha development branch was folded it into the main RC series starting from 1.0 RC8. The rest of this document is relevant to changes introduced in the course of EX + alpha development.

The changes you will see, in a nutshell:

- Better MP3 and OGG support
- Extensible architecture (read: "M.U.G.E.N plugins")
- Loopstart and loopend support, for compatible plugins
- More intuitive volume settings: Master, wave/sfx, BGM
- Volume "offsets" replaced by volume scaling factors
- Various BGM bugfixes
- Improved sound quality
- Probably some new bugs

You MUST use the updated mugen.cfg included in order for BGM to work!

Contents

- Quick FAQ
- Detailed change list
  - mugen.cfg changes
  - CNS changes
  - New stage parameters
  - New system parameters
  - New storyboard parameters
- Previous changelogs
  - New in RC7 EX + alpha
  - New in RC5 EX + alpha
  - New in RC4 EX + alpha
  - RC3 EX + alpha

# Quick FAQ

17. What kind of plugins does this support?

1. M.U.G.E.N only recognizes plugins specifically designed for it. So, for instance, Winamp plugins will not work. You can see the initial EX + alpha blog post for an idea of the kinds of problems involved with non-native plugins.

17. How do I make a plugin for my favorite file type?

1. Consult the plugin SDK.

17. How do I find loop points for my MP3s or OGGs?

1. To get a good result, you will need to open your file in an audio editor and identify the precise points where the music repeats itself. For further details, you may wish to consult loopguide.html in the docs/ directory. This is especially recommended if you are using MP3 files, as there are several tricky issues involved for MP3 in particular.

17. How do I set loop points for my other file types?

1. You can't, yet. Looppoint-compatible plugins haven't yet been made for the other file types.

17. The audio stutters/skips!

1. Try turning up the audio buffer size and/or turning down the mixer sample rate in mugen.cfg ([Sound] section). Also, turn off high-quality resampling if you have it enabled. If you still can't get it to work right, then please report the issue to us, along with your system specs. In your report, try to distinguish between dropouts (a short period of silence), skips (the music jumps ahead by a small amount), and stutters (the music repeats itself briefly).

   For this alpha build, the BGM system tries to keep track of its status. You can find some summary timing statistics for the mixer callback written to the end of mugen.log. You can also see if the system detected a decoder underrun by searching for lines saying "possible read starvation detected!" This information helps us troubleshoot the possible causes of sound corruption.

17. Why are there three Microsoft.VC90.CRT folders? Is this some kind of joke?

1. Those folders are an unfortunate consequence of the way Visual C runtimes are loaded, and are usually required for correct operation. However, there is a way to get rid of them. You need to download and install the Visual C++ 2008 SP1 redistributable package (x86). Once you have done this, the Microsoft.VC90.CRT folders can be safely deleted.

# Detailed change list

The following plugins are in the package. See the comments in mugen.cfg for optional parameters and usage.

- mpg123

  Supports MP3 playback using the libmpg123 decoder, which features several optimized decoding engines written in assembly. Supports looppoints, ReplayGain volume adjustment, and sample-accurate seeking. (Note: seeking will lose an unnoticeable amount of accuracy if the MP3 is at a sample rate different from the mixer sample rate.) mpg123 also fixes the "my MP3 plays slow/fast" problems.

- vorbisplug

  Provides Ogg Vorbis playback using libogg and libvorbisfile. Supports loop points, ReplayGain volume adjustment, and sample-accurate seeking. Uses M.U.G.E.N's built-in resampling service for rate conversion, where necessary. This should provide noticeably better output than the default SDL mixer playback.

- sdlmix

  Wrapper plugin for selected BGM services provided by SDL mixer. This means MIDI, MODs, and other tracker files.

  sdlmix performs seamless looping from the end to the beginning of BGM files (except for MOD/tracker files that naturally loop). However, arbitrary loopstart and loopend points cannot be specified.

The volume system has also been revamped. There is now a master volume setting, a voice/sfx volume setting, and a BGM volume setting. That's it. Volume settings are floating-point numbers between 0% and 100%, and multiply together to give the final output volume. Plugins may also have individual volume multipliers.

For sound effects, the product of all volume scales (master volume, wave volume, and any additional scaling factors in the case of CNS) cannot exceed 100%. If the product is too large, it is reduced to 100%. For plugins, the meaning of a volume scale exceeding 100% (after including plugin-specific volume scaling) is dependent on the particular plugin.

## mugen.cfg changes

- [Options] WavVolume and MidiVolume removed (they were redundant).
- [Sound] SampleRate and BufferSize parameters added. These control the mixer parameters. See the comments in mugen.cfg for more details.
- [Sound] ModVoices, MasterWavVolume, MidiVolume, MP3Volume, ModVolume, CDAVolume parameters removed.
- [Sound] SFXResampleMethod parameter added. This specifies how to perform rate conversion of sound effects. SDL method uses SDL's built-in conversion, which performs no interpolation. This is relatively fast, but gives poor quality results. The libresample method performs bandlimited interpolation, which is higher quality, but may slow down loading by a small amount, and requires more working memory. If using libresample, you can set SFXResampleQuality to 1 for even higher quality, at the cost of more resource usage.
- [Sound] BGMResampleQuality parameter added. This functions the same as SFXResampleQuality, but for music. Note that libresample is always used for rate conversion of music; SDL conversion is not supported.
- [Sound] MasterVolume, WavVolume, BGMVolume parameters used to control volumes. These can also be set in the Options screen.
- [Music] Music group added for plugin specification.
- [Misc] SFXBackgroundMode configures how sounds should be played in the background. Choose from Mute or Play.
- [Misc] BGMBackgroundMode configures how music should be played in the background. Choose from Mute, Pause, or Play.

## CNS changes

- [Data] "volume" parameter is now ignored. Use "volumescale" to specify a volume scaling factor in percent (100, i.e. no change, is the default).
- (PlaySnd) "volume" parameter is now ignored. Use "volumescale" to specify a volume scaling factor in percent.

## New stage parameters

- [Music] bgmvolume (replaces bgvolume)

  bgmvolume is a floating-point multiplier for this stage's volume. 100% is no change. The old parameter, "bgvolume", is deprecated and is ignored.

- [Music] bgmloopstart, bgmloopend

  Specifies the start and end points of the music to loop. If these are set and looping is on, then the music will play from beginning to loopend, then continue looping from loopstart to loopend indefinitely. The exact specification of these parameters is plugin-dependent. For mpg123, the loop points are specified in terms of samples. No other plugins support loop points at present. bgmloopstart defaults to 0 (beginning) and bgmloopend defaults to -1 (end of file).

## New system parameters

- [Music] {title, select, vs, victory}.bgm.loopstart (also loopend and volume)

- [Demo Mode] fight.stopbgm

  If fight.playbgm = 0, then setting fight.stopbgm = 0 allows the title BGM to continue playing during Demo mode.

## New storyboard parameters

- bgm.loopstart, bgm.loopend

# Previous changelogs

These are just the ones we remember.

## New in RC7 EX + alpha

All the RC7 changes, plus:

- Ogg plugin (vorbisplug) supporting loop points and ReplayGain.
- Engine now provides high-quality resampling services (for plugins that require it) using libresample.
- Optional high-quality resampling for sound effects.
- Support for WAV, MP3, and OGG removed from sdlmix plugin, since there are better alternatives.
- Plugin API finalized.

New EX + alpha bug fixes:

- None!

Known EX + alpha bugs:

- Sound and music are sometimes muted when a particular window is focused, regardless of the background mode settings.
- If music is set to pause or mute in the background, it may start playing again if a new BGM is loaded while still in the background.

## New in RC5 EX + alpha

All the RC5 changes, plus:

- BGM loop points can now be specified in storyboards.

New EX + alpha bug fixes:

- loop = 0 mp3's now stop properly.

## New in RC4 EX + alpha

All the RC4 changes, plus:

- Sound effects can be muted when switching out of the M.U.G.E.N window.
- BGM can be paused or muted when switching out of the M.U.G.E.N window.
- Mixer parameters now configurable.
- BGM buffering scheme reworked to address stuttering and dropouts.
- Stage BGM is now guaranteed to start after the first tick, for compatibility with characters that assert NoMusic at the start of the round.
- Upgraded to SDL_mixer 1.2.9. This fixes crashes with WAV music and enables seamless looping for non-MP3 filetypes.

New EX + alpha bug fixes:

- Extension lists were cut off at the first semicolon. They are now comma-separated.
- Storyboard BGMs didn't play, or hanged the application.
- PlaySnd looping parameter didn't work.
- System BGMs didn't always play when loop was 0.
- mpg123 sometimes left a gap with loopend = -1, even on gapless MP3s.

## RC3 EX + alpha

If you use mpg123 for your mp3 files, then the following bugs are fixed:

- MP3's played at the wrong frequency
- Glitchy/scratchy sound when changing tracks
- MP3's with certain ID3 tags would crash the game