L4D2 Custom Sound and Music Tutorial

Note:DUE TO "THE PASSING" UPDATE (April 22, 2010), THIS TUTORIAL IS OUT OF DATE. L4D2 NO LONGER USES _MASTER.CACHE TO CACHE SOUND FILES. THERE IS A POSSIBILITY THAT A NEW SYSTEM IS IN PLACE FOR CUSTOM CONTENT!

Introduction

Adding custom sound and music in a Left 4 Dead 2 map appears to be more flexible than Left 4 Dead (no random sounds, screeching, sound length requirements, strict sound file specs). The following tutorial will first get in-game sounds to work, followed by customizing existing in-game events/sounds (such as music and sound effects), then finally discusses the issue of sound file updating. The techniques in this tutorial maintains two key advantages:

1. Convenience for the end-user
2. Avoids conflicts with audio of other add-ons, existing audio, and versions of the game in different languages.

Warning:Simply packing an updated maps/soundcache/_master.cache file into a VPK is not an ideal solution and should not be done in any case. It causes conflicts with other add-ons that do the same thing and there are unpredictable consequences that will frustrate or inconvenience end-users. Valve is aware of the current situation with custom sounds, although there has been no estimated time that a solution will be patched into the game.

Todo: update tutorial when Valve improves support for custom sounds for add-ons

It is recommended to start with at least the following:

1. A map that can be loaded in-game named however you like - maps/<map name>.bsp
2. A blank per-map soundscript (a .txt file) named maps/<map name>_level_sounds.txt

Sound File Requirements

The following file types and specifications have been known to work:

• .WAV - 16-Bit - 22 Khz and 44 Khz - Mono and Stereo
• .MP3 - 128 Kbps - 22 Khz and 44 Khz - Mono and Stereo

Note:These specifications may not be universal. There may be differences with ambient, music, loops, etc.

Note:You can test out specifications. These are confirmed to work with custom music and ambient sounds.

Note:Sound loops are dependent on .WAV file type

Todo: test out other sound specs

Todo: create table

There are a lot of great free and trial third-party programs for audio conversion.

Preparing the Files

First convert the audio file to a file type and specification that you may consider to work (or use the recommended specs). In most cases, it's just copying over audio files or embedding them.

MP3 Method

.MP3 sound files will play in-game if they are added in the sound/music/<folder or no folder> folder and do not need to be embedded to work in-game or when shipping a VPK.

Note: .MP3 files are a lot smaller than .WAV files, but they require more processing power and therefore lowers either client or server performance

Embedded BSP Method

During development, a custom .WAV file can be played on a test computer without the need to embed it within <map name>.bsp. This is done by updating the sound cache via console:

snd_updateaudiocache

The in-game menu will freeze up temporarily and will eventually output results regarding the sound cache update.

Custom .WAV files should be embedded in a BSP when shipped as a VPK. The files can be placed anywhere within the BSP, preferably under the sound folder for the internal path. Third-party tools like Pakrat currently do not work with L4D2 BSP files.

Note:Successfully playing a custom .WAV file in-game will update the client /maps/soundcache/_master.cache. As a result, the sound file embedded in the BSP can be played by any other BSP after such a change. This can potentially save space if multiple BSP files use the same sound files. Although, getting the user to play the sound once and then restarting the client can be inconvenient.

Create a list of files you would like to embed C:\Program Files\Steam\steamapps\common\left 4 dead 2\bin\<listfile>.txt:

internal_path\file1
external_path\file1
internal_path\file2
external_path\file2
...

• Internal paths ('relative paths') are the location the file will take within the BSP, e.g. materials/metal/new_steel.vmt.
• External paths ('full paths') are the location of the file to be packed, e.g. C:\Users\Public\our_maps\materials\metal\new_steel.vmt.

Note:The internal path should be typed exactly as shown in the example. Use of forward slash ("/") instead of backslash ("\").

1. Copy <map name>.bsp to C:\Program Files\Steam\steamapps\common\left 4 dead 2\bin (Windows 32-Bit, default)
2. Open the Windows Command Prompt, preferable with administrator privileges.
3. Go to bin directory containing bspzip.exe:
   

   cd C:\Program Files\Steam\steamapps\common\left 4 dead 2\bin

4. Embed the files with the following commands:
   

   bspzip -addlist <bspfile> <listfile> <newbspfile>

   Tip:You can quickly select your file in command prompt by typing in the first letters of <map name> and hit TAB to cycle through file names
5. If BSPZIP is looking for gameinfo.txt try:
   

   bspzip -addlist <bspfile> <listfile> <newbspfile> -game "C:\Program Files\Steam\steamapps\common\left 4 dead 2\left4dead2"

6. Optional: You can see if the files have been embedded in the proper internal path by extracting the BSP or viewing the BSP with GCFScape. Note that this is not a way to check if the internal paths are in correct format (the use of slashes).

Creating the Soundscript

Open <map name>_level_sounds.txt with a text editor.

Soundscript Entries

An entry can be played in-game via console or entity, such as ambient_generic or ambient_music. An example entry:

entry.name
{
	channel		CHAN_AUTO
	volume		VOL_NORM
	pitch		PITCH_NORM
	soundlevel	SNDLVL_NORM
	wave		common/null.wav
}

If a value has a space or tab character within it, wrap it in "quote marks".

Examples

Ambience.Siren
{
	channel		CHAN_WEAPON
	volume		VOL_NORM
	pitch		PITCH_NORM
	soundlevel	SNDLVL_NORM
	wave		siren1.wav
}

Arbitrary.Song
{
	channel		CHAN_AUTO
	volume		VOL_NORM
	pitch		PITCH_NORM
	soundlevel	SNDLVL_NORM
	wave		music/singalongsong.wav
}

Foo.Song_mp3
{
	channel		CHAN_STATIC
	volume		VOL_NORM
	pitch		100
	soundlevel	SNDLVL_NORM
	wave		music/songalongdong.mp3
}

Testing In-Game

By Console

1. Open <map name>.bsp
   

   map <map name> coop

2. Test out the sound
   

   playgamesound entry.name

3. In most cases, if a sound refuses to stop playing, stop the sound
   

   stopsound

By Entities

1. Create an ambient_generic, ambient_music, or any other entity that has a property that requires a sound name
   Tip:For ambient_generic, if the sound file is programmed to loop (the actual sound file itself), then un-check the flag "is NOT looped" in order to be able to stop the sound from continuously looping with input StopSound. Ambient_music does not have this flag, but it is not necessary.
2. Change the targetname and change sound name to the soundscript entry of your choice
3. Optional: create an entity that will trigger the sound, if necessary or desired
4. Open <map name>.bsp via console
   

   map <map name> coop

5. Test out the sound via "trigger entity" or console command:
   

   ent_fire <ambient_generic targetname> PlaySound

6. In most cases, if a sound refuses to stop playing, stop the sound via console
   

   stopsound

Soundscapes

Custom soundscapes in L4D2 appear to work well without the need to modify the official soundscapes manifest during development or when shipped as a VPK (named as a per-map soundscape).

Todo: thoroughly test vpks with custom per-map soundscapes with other users or computers

In short, custom soundscapes in L4D2 are text files located in the scripts folder, named "per-map" as scripts/soundscapes_<map name>.txt
There is nothing different about preparing the sound files in order for the soundscapes to play, although using .MP3 files for soundscapes would be unusual.

Customizing Existing Sound and Music

Official Sound and Music Uses Soundscripts

All official in-game sound effects, vocalizations, and music rely on soundscripts to tweak the sound to the correct channels, volume, pitch, etc. With maps/<map name>_level_sounds.txt, you can customize those entries without causing conflicts with other addons and the official campaigns. Simply copy the entries you would like to change to the per-map soundscript.

Soundscript entries can be found in the scripts/game_sounds_*.txt folder by opening pak01_dir.vpk with GCFScape.

A lot of music entries rely on Map Properties, Post-Fix String and nav mesh attributes. For example, the Post-Fix String of the map c5m1_waterfront.bsp is "BigEasy" and it plays its style of intro music in-game, where the nav mesh is marked PLAYER_START and CHECKPOINT.

Interesting Soundscripts

They're all interesting, but here are a couple of them:

• game_sounds_music.txt provides great sample soundscript entries for music. Some entries string together different notes of the same instrument and are played randomly in succession.
• game_sounds_physics.txt has entries for sounds that play during in-game interactions, such as a walking on snow or shooting a concrete wall.

Updating Your Custom Sounds

When Valve ever adds or updates any of their sound files, may it be a change in the contents, length, loop position, etc, all they would have to do is include a new soundcache. This is not the case for custom add-ons.

The first time a custom sound is played in-game, /maps/soundcache/_master.cache is updated to include information about the sound file, such as the file location and a small portion of the sound file. Any changes to the sound file requires an update to the sound cache.

During Development

During development, the sound cache can be updated using a console command:

snd_updateaudiocache

The in-game menu will freeze up temporarily and will eventually output results regarding the sound cache update. Your patience will be rewarded!

For Users

It would be really inconvenient for users to update their sound cache by console command whenever an add-on shipped with updated sound files. One workaround would be changing the filenames and soundscript entries of updated sound files. You can devise a naming scheme that denotes an updated sound file.

Warning:Simply packing an updated maps/soundcache/_master.cache file into a VPK is not an ideal solution and should not be done in any case. It causes conflicts with other add-ons that do the same thing and there are unpredictable consequences that will frustrate or inconvenience end-users. Valve is aware of the current situation with custom sounds, although there has been no estimated time that a solution will be patched into the game.

Troubleshooting

Todo: troubleshooting common problems

See also

• ambient_generic
• ambient_music
• Looping a Sound
• Music Composition
• Sound and Music
• Soundcache
• Sound Download Sites
• Soundscapes
• Soundscripts
• Category:Sound System