What file formats can be used with extraSounds:

[The Martian]

Do I need to use .wav or can other formats like FLAC also be used to add new sounds?

[Solarius Scorch]

Do I need to use .wav or can other formats like FLAC also be used to add new sounds?

.ogg works fine. .mp3 doesn't. I don't know about .flac.

[The Martian]

It appears that .flac sound files seem to work as well.

Is it a good idea to mix audio formats or should all sound files be the same type?

Example (Mixed):

Code: [Select]

extraSounds:
  - type: BATTLE.CAT
    files:
      68: Resources/Sound/OBJECT_ONE_Activate.flac
      69: Resources/Sound/OBJECT_TWO_Activate.wav
      70: Resources/Sound/OBJECT_TWO_Deactivate.wav
      71: Resources/Sound/OBJECT_THREE_Activated.flac
Example (Same):

Code: [Select]

extraSounds:
  - type: BATTLE.CAT
    files:
      68: Resources/Sound/OBJECT_ONE_Activate.wav
      69: Resources/Sound/OBJECT_TWO_Activate.wav
      70: Resources/Sound/OBJECT_TWO_Deactivate.wav
      71: Resources/Sound/OBJECT_THREE_Activated.wav

[Chuckebaby]

I can't help you on the compatibility issue but one thing I do know is audio.
FLAC is indeed higher quality than a compressed format such as Ogg/vorbis. However FLAC is 3 times the size as compressed formats such as Ogg.
To give you an example, a 3 minutes song for FLAC is approx 15MB where as a 3 minute song in Ogg is around 4MB.

I'm sure your not going to be racking up gigs of data in 3 second samples but it's just something to keep in mind when your mod size goes up.