L4D2 Custom Sound and Music Tutorial

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 requirements). 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).

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

Note:You can test out other specifications. These are just confirmed to work.

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

Custom .WAV files must be embedded in a BSP to work and when shipped as a VPK, but they can be placed anywhere, 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:It is recommended that the internal path be typed exactly as shown in the example (use of forward slash ("/") instead of backslash ("\")

1. It is recommended to copy the <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"

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 via console
   

   map <map name>.bsp coop

2. Test out the sound via console
   

   playgamesound entry.name

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, test out the sound before changing the default flags
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
4. Open <map name>.bsp via console
   

   map <map name>.bsp coop

5. Test out the sound via console command:
   

   ent_fire <ambient_generic targetname> PlaySound

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 <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.

Troubleshooting

Todo: troubleshooting common problems