# Audio File Extensions

<p class="callout info">These are the audio file types you will be interacting with.</p>

##### **.wav**

Edited SFX, VO, &amp; MUSIC files must be converted into the WAV format before they can be converted into WEM files.  
WAV files **SHOULD NOT** be included in your mod.  
<span style="text-decoration: underline;">Example:</span>  
`<strong>cultist_base_music_main_heavy_0_id#156134790.wav</strong>`

##### **.wem**

The format that SFX, VO, &amp; MUSIC files have been converted into the WEM format.  
WEM files **SHOULD** be include in your mod.  
<span style="text-decoration: underline;">Example:</span>  
`<strong>cultist_base_music_main_heavy_0_id#156134790.wem</strong>`

##### **.snd**

These contain the audio files. They **CANNOT** be directly modified by a conventional audio editor.  
Instead, tools are used to extract individual audio audio files.  
<span style="text-decoration: underline;">Example:</span>  
**`music.snd`**

##### **.pck**

These contain the audio resources. They **CANNOT** be directly modified by a conventional audio editor.  
However, [Fusion Tools](https://wiki.eternalmods.com/books/eternal-audio-modding/page/audio-length) can directly modify PCK files.  
<span style="text-decoration: underline;">Example:  
</span>`<strong>mus.pck</strong>`

<p class="callout danger">**PCK** files modified by **[Fusion ](https://www.nexusmods.com/site/mods/1812)[Tools](https://www.nexusmods.com/site/mods/1812)** are not supported by the [**Atlan Mod Loader**](https://github.com/FlavorfulGecko5/EntityAtlan/releases).  
which is a program that allows certain mods type to be injected.</p>

<p class="callout info">See [Creating Audio Mods](https://wiki.eternalmods.com/books/eternal-audio-modding/page/creating-audio-mods) for more information.</p>

#### **Legacy Formats**

##### **.ogg**

Extracted MUSIC files from "**music**", "**music\_patch\_1**", &amp; **"music\_patch\_2"** can be in this format.  
OGG files **SHOULD NOT** be included in your mod.  
<span style="text-decoration: underline;">Example:</span>  
`<strong>cultist_base_music_main_heavy_0_id#156134790.ogg</strong>`

##### **.opus**

Extracted SFX &amp; VO files from "**sfx**", "**sfx\_patch\_1**", "**vo\_English(US)**", etc can be in this format.  
OPUS files **SHOULD NOT** be included in your mod.  
<span style="text-decoration: underline;">Example:</span>  
`<strong>ammo_bfg_id#373311939.opus</strong>`