VoxaTrace/com.musicmuni.voxatrace.sonix/SonixMixer

SonixMixer

Multi-track audio mixer with synchronized playback.

Quick Start

Kotlin

val mixer = SonixMixer.create()
mixer.addTrack("backing", "/path/to/backing.mp3")  // Auto-decodes
mixer.addTrack("vocal", "/path/to/vocal.mp3")
mixer.play()

// Control individual tracks
mixer.setTrackVolume("vocal", 0.5f)  // Reduce vocal volume
mixer.fadeTrackVolume("vocal", 0f, 2000)  // Fade out over 2 seconds

// Release when done
mixer.release()

Swift

let mixer = SonixMixer.create(
    config: .default,
    audioSession: .playback
)
await mixer.addTrack(name: "backing", filePath: "/path/to/backing.mp3")
await mixer.addTrack(name: "vocal", filePath: "/path/to/vocal.mp3")
mixer.play()

// Control individual tracks
mixer.setTrackVolume(name: "vocal", volume: 0.5)
mixer.fadeTrackVolume(name: "vocal", targetVolume: 0, durationMs: 2000)

// Release when done
mixer.release()

Builder Pattern (Advanced)

Kotlin

val config = SonixMixerConfig.Builder()
    .loopCount(3)
    .onPlaybackComplete { println("All loops done!") }
    .onLoopComplete { index -> println("Completed loop $index") }
    .build()
val mixer = SonixMixer.create(config)

StateFlows

StateFlow	Type	Description
`currentTime`	Long	Current playback time in ms
`isPlaying`	Boolean	True while playing
`error`	SonixError?	Error state

Platform Notes

iOS

Uses AVAudioEngine for synchronized playback
Automatically configures audio session

Android

Uses AudioTrack with synchronized playback
Automatically configures audio focus

Common Pitfalls

addTrack is suspend: Call from coroutine or use addTrack(name, data, rate, channels)
Forgetting to release: Call release() when done
Track names must be unique: Adding a track with same name replaces it
Different sample rates: Tracks are automatically resampled to match