Visualization toolkit for vocal and pitch apps: scrolling pitch canvases, real-time indicators, offline charts, navigation components, and composable primitives to render users' sung pitch effectively.
Compose Multiplatform visualization library for singing and pitch apps, on Android and iOS. Scrolling practice canvases, live pitch monitors, charts, meters, and segment and lyrics navigation: VoxaVis draws what your users sing.
VoxaVis renders what you give it. It does not capture audio, detect pitch or score singing. Pair it with VoxaTrace or any pitch source.
Documentation: musicmuni.github.io/voxavis. Upgrading from 1.x? See MIGRATION.md. What changed in each release: CHANGELOG.md.
Every component reads MaterialTheme.colorScheme, so an app with its own
Material 3 theme needs nothing else. Apps without one wrap VoxaVis in
VoxaVisTheme.
dependencies {
implementation("com.musicmuni:voxavis:2.0.0")
}
In Xcode: File > Add Package Dependencies, enter
https://github.com/musicmuni/voxavis, or in Package.swift:
.package(url: "https://github.com/musicmuni/voxavis", from: "2.0.0")
pod 'VoxaVis', :podspec => 'https://raw.githubusercontent.com/musicmuni/voxavis/2.0.0/VoxaVis.podspec'
VoxaVis needs a licence. Call VV.initialize once at app start, before the
first feature component (SingingPractice, InstantPitchMonitor,
ScrollingPitchMonitor, PracticeReview) is shown; those throw
VoxaVisNotInitializedException without it. Charts, meters, navigation and
primitives do not need it.
The recommended setup keeps your API key on your server. Your backend exposes
one endpoint that registers a device with the licence server using your key
and returns the device token; the app passes that endpoint to initialize.
It is the same proxy contract VoxaTrace uses, so one endpoint can serve both
SDKs; what the endpoint receives and returns is in VoxaTrace's
authentication guide. Contact
support@musicmuni.com for a key.
Android:
class MyApp : Application() {
override fun onCreate() {
super.onCreate()
VV.initialize(
proxyEndpoint = "https://your-server.com/voxatrace/register",
context = this,
// Optional: the Authorization header your endpoint expects.
proxyAuth = { "Bearer ${currentUserToken()}" },
)
}
}
proxyAuth is a suspend function, for a login token you fetch
asynchronously. proxyAuthProvider is the same for a token you already hold.
Pass one or neither. Your app needs the INTERNET permission.
iOS:
do {
try VV.initialize(
proxyEndpoint: "https://your-server.com/voxatrace/register",
proxyAuthProvider: { "Bearer \(currentUserToken())" }
)
} catch {
print("VoxaVis licence error: \(error)")
}
Only a 403 from your endpoint switches the SDK off. A device that already holds a token never waits on the network at start-up.
A practice screen: the teacher's line, the learner's live pitch, and a playhead your player drives.
@Composable
fun PracticeScreen(
lesson: SingingPracticeResources,
pitchBuffer: CircularPitchBuffer, // fill it from your pitch detector
positionMs: MutableLongState, // write your player's position once per frame
) {
val clock = remember(positionMs) { { positionMs.longValue } }
SingingPractice(
resources = lesson,
currentTimeMs = clock,
performancePitch = pitchBuffer,
)
}
The playhead is a reader, called while drawing. Keep it in a remember: a
playing session then moves by one transform per frame instead of recomposing
the screen.
The learner's line is drawn only inside SegmentType.PERFORMANCE segments:
what the microphone hears while the teacher sings is not shown. For free
singing with no lesson, pass one performance segment that covers the track.
Describe the lesson once:
val lesson = SingingPracticeResources.create(
mode = SessionMode.Singafter,
trackLengthMs = 30_000L,
segments = phrases, // List<Segment>: who sings when
referencePitch = teacherLine, // PitchContourData, in cents
gridLines = scaleLines, // List<GridLine>: the notes of the scale
)
A live pitch monitor needs only the buffer:
InstantPitchMonitor(
currentTimeMs = nowMs,
performancePitch = pitchBuffer,
pitchRange = 100f..900f,
)
demo-apps/android and demo-apps/ios
show every component with mock data. Each has a README with setup steps.
Commercial License. See LICENSE. Contact support@musicmuni.com for terms.
| Group | Components |
|---|
| Features | SingingPractice (the practice canvas: teacher's line, the learner's pitch, phrases, takes, count-in and rhythm lane), InstantPitchMonitor, ScrollingPitchMonitor, PracticeReview |
| Primitives | PitchGrid, PitchContour, PitchBall, PitchTrail, ReferenceLine, NoteBars, SegmentBands, NowLine |
| Layouts | PitchSpace, ScrollingPitchSpace: coordinate systems the primitives draw in |
| Components | Note accuracy, radar, vocal range, scatter and score trend charts; score cards and metrics lists; ring, tuning, beat, level and confidence meters |
| Navigation | SegmentScrubber, SegmentedSeekBar, LyricsOverlay |
| Theme | VoxaVisTheme, VoxaVisColors, ScoreBands |
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