IngameSounds.def

Structure
File header
 * Category 1
 * Sound 1 label
 * Sound 1 file 1
 * Sound 1 file 2
 * Sound 1 file N
 * Sound 2
 * Sound N
 * Category 2
 * Category N

File header
IngameSound.def begins with E803 followed by the file's bytecount.

Sound category
Each new category begins with 4C04 followed by the category's bytecount. Then as in the table below.

Sounds
Each new sound begins with B004 and it's bytecount. Then as in the table below.

For each sound label several sound files can be assigned. Each new sound file begins with 1405 and it's bytecount. Then as in the table below.