DSWaveformImage offers a few interfaces for the purpose of drawing the envelope waveform of audio data in iOS, iPadOS and Mac Catalyst. To do so, you can use
WaveformImageView
(UIKit) /WaveformView
(SwiftUI) to render a static waveform from an audio file orWaveformLiveView
(UIKit) /WaveformLiveCanvas
(SwiftUI) to realtime render a waveform of live audio data (e.g. fromAVAudioRecorder
)WaveformImageDrawer
to generate a waveformUIImage
from an audio file
Additionally, you can get a waveform's (normalized) [Float]
samples directly as well by
creating an instance of WaveformAnalyzer
.
For a practical real-world example usage of a SwiftUI live audio recording waveform rendering, see RecordingIndicatorView.
You may also find the following iOS controls written in Swift interesting:
- SwiftColorWheel - a delightful color picker
- QRCode - a customizable QR code generator
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
If you're feeling in the mood of sending someone else a lovely gesture of appreciation, maybe check out my iOS app 💌 SoundCard to send them a real postcard with a personal audio message.
- use SPM: add
https://github.com/dmrschmidt/DSWaveformImage
and set "Up to Next Major" with "10.0.0"
Deprecated or discouraged but still possible alternative ways for older apps:
- since it has no other dependencies you may simply copy the
DSWaveformImage
folder directly into your project - use carthage:
github "dmrschmidt/DSWaveformImage" ~> 7.0
- or, sunset since 6.1.1:
use cocoapods:pod 'DSWaveformImage', '~> 6.1'
DSWaveformImage
provides 3 kinds of tools to use
- native SwiftUI views - SwiftUI example usage code
- native UIKit views - UIKit example usage code
- access to the raw renderes and processors
@State var audioURL = Bundle.main.url(forResource: "example_sound", withExtension: "m4a")!
WaveformView(audioURL: $audioURL)
@StateObject private var audioRecorder: AudioRecorder = AudioRecorder() // just an example
WaveformLiveCanvas(samples: $audioRecorder.samples)
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
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.
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
}
}
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)")
}
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
}
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. Using WaveformLiveView
may be another one in conjunction with AVAudioPlayer
(note that AVPlayer
does not offer
the same simple access to its audio metering data, so is not as suitable out of the box).
For one example way to display waveforms for audio files on remote URLs see dmrschmidt#22.
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-recording.mov
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 removed in 6.0.0 to simplify the API.
See Usage
for current usage.
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.
![Screenshot](https://github.com/dmrschmidt/DSWaveformImage/raw/main/screenshot3.png?raw=true)