This is a feature not yet fully implemented due to further FMOD integration being preferable. The documentation should remain the same, but for now, this feature is not accessible.
TL;DR, FMOD is optionally used with Ryle Radio to stream audio files at runtime. It does not have any further integration yet.
Why is it used?
Inside ClipRadioTrack, we access data from the provided AudioClip using the built-in method GetData(...). However, this method requires that the entire audio clip is decompressed before the data can be obtained- that is, the clip has to be loaded at the game startup. With only a few short audio clips this can be negligible, but once you start using longer tracks or full songs, a significant amount of waiting happens whenever you start the game or Play Mode- quickly becoming a major detriment to development.
The solution that Unity gives us to this problem is the Streaming load type. Normally, this would allow the audio to be loaded in small chunks over time, making big audio files load significantly faster. Unfortunately, this does not work for us- in order to use GetData(...), the whole clip needs to be loaded, as previously described. Attempting to use Streaming (or even CompressedInMemory) spits back errors at runtime.
This leaves as with an issue, then- how do we stream audio for big files? The answer I’ve gone with is FMOD.
What does it do?
FMOD for Unity is an incredibly popular third-party audio system that allows for complex audio in a Unity project, though the base FMOD works with countless engines and systems. It also provides low-level audio loading and streaming that we can utilise in Ryle Radio.
We load the selected AudioClip into FMOD’s programmer audio, then over time stream chunks into a buffer that we play through Unity. The only difference you’ll notice is that your game starts up faster :)
When should I use it?
If you’re using large audio files, e.g: songs, ambience, it could be worthwhile using FMOD streaming in order to reduce load times. You usually should be able to get by without it by using AudioClip.loadInBackground, but huge audio clips may struggle.
However, do note that using this feature requires that the entire FMOD for Unity package be installed. This is a fairly substantial package that includes a lot of other functionality, so if you’re averse to installing a large package you may be better off avoiding this feature.
In short: if you’re having slow loading and are happy installing an extra package, try out FMOD streaming.
How do I use it?
First of all, install FMOD for Unity to your project through the Asset Store (or some other method, though that’s untested).
You should then be able to select “FMOD Audio Streaming” in the list of track options on a RadioData, same place you’d select “Procedural” or “Audio Clip”.
What could change?
I have the possibility of adding further FMOD integration on my radar. If inclusion of the package into FMOD itself or linked closer into its functionality is a feature people would use, I’m very happy to implement it :) For the current version, though, integration is limited to audio streaming.