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dmrschmidt/DSWaveformImage 11.0.1
Generate waveform images from audio files on iOS & macOS in Swift. Native SwiftUI & UIKit views.
⭐️ 521
πŸ•“ 2 weeks ago
iOS macOS
.package(url: "https://github.com/dmrschmidt/DSWaveformImage.git", from: "11.0.1")

DSWaveformImage - iOS & macOS realtime audio waveform rendering

Swift Package Manager compatible

DSWaveformImage offers a native interfaces for drawing the envelope waveform of audio data in iOS, iPadOS, macOS or via Catalyst. To do so, you can use

Additionally, you can get a waveform's (normalized) [Float] samples directly as well by creating an instance of WaveformAnalyzer.

Example UI (included in repository) --src="https://raw.github.com/dmrschmidt/DSWaveformImage/main/-----

For a practical real-world example usage of a SwiftUI live audio recording waveform rendering, see RecordingIndicatorView.

Audio Recorder Example

More related iOS Controls

You may also find the following iOS controls written in Swift interesting:

If you really like this library (aka Sponsoring)

I'm doing all this for fun and joy and because I strongly believe in the power of open source. On the off-chance though, that using my library has brought joy to you and you just feel like saying "thank you", I would smile like a 4-year old getting a huge ice cream cone, if you'd support my via one of the sponsoring buttons β˜ΊοΈπŸ’•

If you're feeling in the mood of sending someone else a lovely gesture of appreciation, maybe check out my iOS app πŸ’Œ SoundCard to send them a real postcard with a personal audio message.

Buy Me A Coffee


  • use SPM: add https://github.com/dmrschmidt/DSWaveformImage and set "Up to Next Major" with "11.0.0"
import DSWaveformImage // for core classes to generate `UIImage` / `NSImage` directly
import DSWaveformImageViews // if you want to use the native UIKit / SwiftUI views

Deprecated or discouraged but still possible alternative ways for older apps:

  • since it has no other dependencies you may simply copy the Sources folder directly into your project
  • use carthage: github "dmrschmidt/DSWaveformImage" ~> 7.0 (last supported version is 10)
  • or, sunset since 6.1.1: use cocoapods: pod 'DSWaveformImage', '~> 6.1'


DSWaveformImage provides 3 kinds of tools to use

The core renderes and processors as well as SwiftUI views natively support iOS & macOS, using UIImage & NSImage respectively.


WaveformView - renders a one-off waveform from an audio file:

@State var audioURL = Bundle.main.url(forResource: "example_sound", withExtension: "m4a")!
WaveformView(audioURL: audioURL)

WaveformLiveCanvas - renders a live waveform from (0...1) normalized samples:

@StateObject private var audioRecorder: AudioRecorder = AudioRecorder() // just an example
WaveformLiveCanvas(samples: audioRecorder.samples)


WaveformImageView - renders a one-off waveform from an audio file:

let audioURL = Bundle.main.url(forResource: "example_sound", withExtension: "m4a")!
waveformImageView = WaveformImageView(frame: CGRect(x: 0, y: 0, width: 500, height: 300)
waveformImageView.waveformAudioURL = audioURL

WaveformLiveView - renders a live waveform from (0...1) normalized samples:

Find a full example in the sample project's RecordingViewController.

let waveformView = WaveformLiveView()

// configure and start AVAudioRecorder
let recorder = AVAudioRecorder()
recorder.isMeteringEnabled = true // required to get current power levels

// after all the other recording (omitted for focus) setup, periodically (every 20ms or so):
recorder.updateMeters() // gets the current value
let currentAmplitude = 1 - pow(10, recorder.averagePower(forChannel: 0) / 20)
waveformView.add(sample: currentAmplitude)



Note: Calculations are always performed and returned on a background thread, so make sure to return to the main thread before doing any UI work.

Check Waveform.Configuration in WaveformImageTypes for various configuration options.

WaveformImageDrawer - creates a UIImage waveform from an audio file:

let waveformImageDrawer = WaveformImageDrawer()
let audioURL = Bundle.main.url(forResource: "example_sound", withExtension: "m4a")!
waveformImageDrawer.waveformImage(fromAudioAt: audioURL, with: .init(
                                  size: topWaveformView.bounds.size,
                                  style: .filled(UIColor.black),
                                  position: .top)) { image in
    // need to jump back to main queue
    DispatchQueue.main.async {
        self.topWaveformView.image = image

WaveformAnalyzer - calculates an audio file's waveform sample:

let audioURL = Bundle.main.url(forResource: "example_sound", withExtension: "m4a")!
waveformAnalyzer = WaveformAnalyzer(audioAssetURL: audioURL)
waveformAnalyzer.samples(count: 200) { samples in
    print("so many samples: \(samples)")

async / await Support

The public API has been updated in 9.1 to support async / await. See the example app for an illustration.

public class WaveformAnalyzer {
    func samples(count: Int, qos: DispatchQoS.QoSClass = .userInitiated) async throws -> [Float]

public class WaveformImageDrawer {
    public func waveformImage(
        fromAudioAt audioAssetURL: URL,
        with configuration: Waveform.Configuration,
        qos: DispatchQoS.QoSClass = .userInitiated
    ) async throws -> UIImage

Playback Progress Indication

If you're playing back audio files and would like to indicate the playback progress to your users, you can find inspiration in this ticket. There's various other ways of course, depending on your use case and design. One way to achieve this in SwiftUI could be

// @State var progress: src="https://raw.github.com/dmrschmidt/DSWaveformImage/main/at = 0 // must be between 0 and 1

ZStack(alignment: .leading) {
    WaveformView(audioURL: audioURL, configuration: configuration)
    WaveformView(audioURL: audioURL, configuration: configuration.with(style: .filled(.red)))
        .mask(alignment: .leading) {
            GeometryReader { geometry in
                Rectangle().frame(width: geometry.size.width * progress)

This will result in something like the image below.

playback progress waveform

Keep in mind though, that this approach will calculate and render the waveform twice initially. This will be more than fine for 95% of typical use cases. If you do have very strict performance requirements however, you may want to use WaveformImageDrawer directly instead of the build-in views. There is currently no plan to integrate this as a 1st class citizen as every app will have different requirements, and WaveformImageDrawer as well as WaveformAnalyzer are as simple to use asrc="https://raw.github.com/dmrschmidt/DSWaveformImage/main/ views themselves.

Loading remote audio files from URL

For one example way to display waveforms for audio files on remote URLs see https://github.com/dmrschmidt/DSWaveformImage/issues/22.

What it looks like

Waveforms can be rendered in 3 different styles: .filled, .gradient and .striped.

Similarly, there are 3 positions relative to the canvas, .top, .middle and .bottom.

The effect of each of those can be seen here:


Live waveform rendering



In 11.0.0 the library was split into two: DSWaveformImage and DSWaveformImageViews. If you've used any of the native views bevore, just add the additional import DSWaveformImageViews. The SwiftUI views have changed from taking a Binding to the respective plain values instead.

In 9.0.0 a few public API's have been slightly changed to be more concise. All types have also been grouped under the Waveform enum-namespace. Meaning WaveformConfiguration for instance has become Waveform.Configuration and so on.

In 7.0.0 colors have moved into associated values on the respective style enum.

Waveform and the UIImage category have been removedsrc="https://raw.github.com/dmrschmidt/DSWaveformImage/main/.0.0 to simplify the API. See Usage for current usage.

See it live in action

SoundCard - postcards with sound lets you send real, physical postcards with audio messages. Right from your iOS device.

DSWaveformImage is used to draw the waveforms of the audio messages that get printed on the postcards sent by SoundCard - postcards with audio.





Stars: 521
Last commit: 2 weeks ago
jonrohan Something's broken? Yell at me @ptrpavlik. Praise and feedback (and money) is also welcome.

Release Notes

2 weeks ago

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