As with Meshes or Textures, the workflow for Audio File assets is designed to be smooth and trouble free. Unity can import almost every common file format but there are a few details that are useful to be aware of when working with Audio Files.
Audio in Unity is either Native or Compressed. Unity supports most common formats (see the list below) and will import an audio file when it is added to the project. The default mode is Native, where the audio data from the original file is imported unchanged. However, Unity can also compress the audio data on import, simply by enabling the Compressed option in the importer. (iOS projects can make use of the hardware decoder - see the iOS documentation for further details). The difference between Native and Compressed modes are as follows:-
Native: Use Native (WAV, AIFF) audio for short sound effects. The audio data will be larger but sounds won’t need to be decoded at runtime.
Compressed: The audio data will be small but will need to be decompressed at runtime, which entails a processing overhead. Depending on the target, Unity will encode the audio to either Ogg Vorbis (Mac/PC/Consoles) or MP3 (Mobile platforms). For the best sound quality, supply the audio in an uncompressed format such as WAV or AIFF (containing PCM data) and let Unity do the encoding. If you are targeting Mac and PC platforms only (including both standalones and webplayers) then importing an Ogg Vorbis file will not degrade the quality. However, on mobile platforms, Ogg Vorbis and MP3 files will be re-encoded to MP3 on import, which will introduce a slight quality degradation.
Any Audio File imported into Unity is available from scripts as an Audio Clip instance, which is effectively just a container for the audio data. The clips must be used in conjunction with Audio Sources and an Audio Listener in order to actually generate sound. When you attach your clip to an object in the game, it adds an Audio Source component to the object, which has Volume, Pitch and a numerous other properties. While a Source is playing, an Audio Listener can “hear” all sources within range, and the combination of those sources gives the sound that will actually be heard through the speakers. There can be only one Audio Listener in your scene, and this is usually attached to the Main Camera.
| Format | Compressed as (Mac/PC) | Compressed as (Mobile) |
|---|---|---|
| MPEG(1/2/3) | Ogg Vorbis | MP3 |
| Ogg Vorbis | Ogg Vorbis | MP3 |
| WAV | Ogg Vorbis | MP3 |
| AIFF | Ogg Vorbis | MP3 |
| MOD | - | - |
| IT | - | - |
| S3M | - | - |
| XM | - | - |
See the Audio Overview for more information on using sound in Unity.