Module kira::mixer

Organizes and applies effects to audio.

All sounds in Kira are processed by the mixer before being sent to the operating system’s audio driver. The mixer is made up of a number of tracks, which are like continuously flowing rivers of audio data. Each track can have a series of effects, which are processors that transform input audio in some way and output the transformed audio.

There are three kinds of mixer tracks:

• The main track, which all audio eventually reaches
• Sub-tracks, which can each have their own volume levels, sets of effects, and parent tracks (either the main track or another sub-track)
• Send tracks, which sub-tracks can be additionally routed to. These are useful for applying effects to sounds from multiple sub-tracks.

Each instance of a sound or arrangement can have its audio sent to the main track, a sub-track, or a send track.

Here’s an example of a way you might want to set up a mixer:

┌──Sub──┐    ┌──Sub──┐    ┌──Sub───┐
│ Music │    │  SFX  │    │Ambience├─────┐
└───┬───┘    └───┬─┬─┘    └────┬───┘     │
    │            │ │           │         ▼
    │            │ │           │      ┌─Send─┐
    │            │ └───────────┼─────►│Reverb│
    │            │             │      └──┬───┘
    │     ┌──────▼─────┐       │         │
    │     │            ◄───────┘         │
    └─────► Main track │                 │
          │            ◄─────────────────┘
          └────────────┘

Using sub-tracks for different categories of audio allows for easy control of the volume levels of the music, sfx, etc. Using a send track for reverb allows you to use the same reverb effect for multiple kinds of audio, reducing CPU usage and code repetition (of course, this only applies if you want SFX and ambience to have the same reverb effect).

For each track, audio is fed through each effect in order. The signal flow for a track with a filter added first and then a reverb looks like this:

  Input audio
       │
       ▼
┌────Track─────┐
│      │       │
│   ┌──▼───┐   │
│   │Filter│   │
│   └──┬───┘   │
│      │       │
│   ┌──▼───┐   │
│   │Reverb│   │
│   └──┬───┘   │
│      │       │
└──────┼───────┘
       │
       ▼
  Output audio

Modules

effect

Modifies audio in real time.

Structs

MainTrackHandle	Allows you to control the main mixer track.
SendTrackHandle	Allows you to control a mixer send track.
SendTrackId	A unique identifier for a send track.
SendTrackSettings	Settings for a mixer send-track.
SubTrackHandle	Allows you to control a mixer sub-track.
SubTrackId	A unique identifier for a sub-track.
SubTrackSettings	Settings for a mixer sub-track.
TrackSends	A mapping of send tracks to volume levels.

Enums

TrackIndex

An identifier for a mixer track.