Examples>Levels
Levels
You can grab the current levels of each channel from an audio sample as it is playing back. To do so you’ll need to set up a timer and turn on metering, but otherwise it’s pretty easy:
player.meteringEnabled = true
player.averagePower(0)Example
let audioPlayer = AudioPlayer("C4Loop.aif")!
var avgL, avgR, peakL, peakR: Line!
override func setup() {
audioPlayer.play()
audioPlayer.loops = true
audioPlayer.meteringEnabled = true
audioPlayer.play()
createMeterLines()
let t = Timer(interval: 1/30.0) {
self.updateMeters()
}
t.start()
}
func updateMeters() {
ShapeLayer.disableActions = true
audioPlayer.updateMeters()
avgL.strokeEnd = pow(10, 0.05 * audioPlayer.averagePower(0))
avgR.strokeEnd = pow(10, 0.05 * audioPlayer.averagePower(1))
peakL.strokeEnd = pow(10, 0.05 * audioPlayer.peakPower(0))
peakR.strokeEnd = pow(10, 0.05 * audioPlayer.peakPower(1))
ShapeLayer.disableActions = false
}
func createMeterLines() {
let dx = Vector(x: canvas.width/4.0, y: 0)
var points = (Point(0, canvas.height), Point())
points.0 += dx/2.0
points.1 += dx/2.0
avgL = Line(points)
avgL.lineCap = .Butt
avgL.lineWidth = dx.x
avgL.strokeColor = C4Pink
points.0 += dx
points.1 += dx
avgR = Line(points)
avgR.lineCap = .Butt
avgR.lineWidth = dx.x
avgR.strokeColor = C4Pink
points.0 += dx
points.1 += dx
peakL = Line(points)
peakL.lineCap = .Butt
peakL.lineWidth = dx.x
points.0 += dx
points.1 += dx
peakR = Line(points)
peakR.lineCap = .Butt
peakR.lineWidth = dx.x
points.0 += dx
points.1 += dx
canvas.add(avgL)
canvas.add(avgR)
canvas.add(peakL)
canvas.add(peakR)
}