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MIDI Player

Play MIDI files in Garry's Mod! You can load MIDI files from your garrysmod folder, or from an internet URL.


Step 1: Acquire MIDI files
Put some MIDI files in your 'GarrysMod/garrysmod' folder, or find some somewhere online.
The Video Game Music Archive[vgmusic.com] has plenty of MIDIs with varying quality.

Step 2: Get in-game
You should know how to do this. Start a single-player game, or join a server that has this addon installed.

Step 3: Open the spawn menu
You should also know how to do this. Just press and hold 'Q'.

Step 4: Utilities tab
It's the one on the far right.

Step 5: Select MIDI Player - Control
You should see it in your tool list.

Step 6: Use interface to load a MIDI
Either double-click a MIDI file you placed into your garrysmod folder earlier, or paste in a URL and click 'Load'

Step 7: Listen to music

This MIDI player is far from perfect. Several issues with sound playback in the Source engine prevent any improvements. The only likely path to improving this MIDI player is for Garry's Mod to ditch its outdated Chrome 18 based embedded browser (Awesomium) with one based on modern versions of Chrome (Chromium Embedded Framework). Then, an HTML5 implementation of a more accurate MIDI player can be used. Until then, here's whats wrong, in the order it bothers me the most:

• Notes that require a sound to be pitch-shifted by a factor higher than 2.55 will be ignored. While an upper limit makes sense, Source made it way too low.
  
• If too many notes are played at once using the same sound file, some of them will be ignored. This is due to limitations in Source.
  
• The pitch of a note will not always be accurate. This is due to Source forcing what should be a floating point number into an 8-bit integer.
  
• Volume of notes may be wrong. The cause of this is unknown, but is probably the fault of Source. An HTML5 version of the MIDI player using the same methods produces correct output.
  
• The implementation of the SoundFont 2 spec is not complete. This is due to limitations in Source, and me being lazy.

This addon supports custom soundfonts, however, the Source Engine cannot play sounds directly from the soundfont. The sounds need to be extracted, have their sampling rate changed to something that the Source Engine will play, saved as *.wav files, and placed in the appropriate folder. I've included a Lua function that can do most of this for you, but you still have to do a little legwork yourself.

First, you must place the soundfont into your garrysmod folder. Then, run some Lua code:

midi.LoadSF("mysoundfont.sf2")
midi.sf:DumpSamples()

This will dump out the sounds into your garrysmod data folder, with the naming convention "garrysmod/data/mysoundfont.sf2/*.wav.txt". You must remove the .txt extension from each sound file, then move the whole "mysoundfont.sf2" folder into "garrysmod/sound/soundfont". The final path of the sounds should be "garrysmod/sound/soundfont/mysoundfont.sf2/*.wav".

Then you are all set. Any time you want to use that soundfont, you must run this bit of Lua:

midi.LoadSF("mysoundfont.sf2")

Any midi you play after this will use the new soundfont, until the client changes maps, disconnects, or exits.

Though this is possible to do, I do not recommend it. Most soundfonts will probably sound horrible due to the Source Engine limitations I mentioned.