A Swift camera system designed for easy integration, customized media capture

NextLevel

NextLevel is a Swift camera system designed for easy integration, customized media capture, and image streaming in iOS. Integration can optionally leverage AVFoundation or ARKit.

Need a different version of Swift?

• 5.0 - Target your Podfile to the latest release or master
• 4.2 - Target your Podfile to the swift4.2 branch

Quick Start

# CocoaPods
pod "NextLevel", "~> 0.16.3"

# Carthage
github "nextlevel/NextLevel" ~> 0.16.3

# Swift PM
let package = Package(
    dependencies: [
        .Package(url: "https://github.com/nextlevel/NextLevel", majorVersion: 0)
    ]
)

Alternatively, drop the NextLevel source files or project file into your Xcode project.

Important Configuration Note for ARKit and True Depth

ARKit and the True Depth Camera software features are enabled with the inclusion of the Swift compiler flag USE_ARKIT and USE_TRUE_DEPTH respectively.

Apple will reject apps that link against ARKit or the True Depth Camera API and do not use them.

If you use Cocoapods, you can include -D USE_ARKIT or -D USE_TRUE_DEPTH with the following Podfile addition or by adding it to your Xcode build settings.

  installer.pods_project.targets.each do |target|
    # setup NextLevel for ARKit use
    if target.name == 'NextLevel'
      target.build_configurations.each do |config|
        config.build_settings['OTHER_SWIFT_FLAGS'] = ['$(inherited)', '-DUSE_ARKIT']
      end
    end
  end

Overview

Before starting, ensure that permission keys have been added to your app's Info.plist.

<key>NSCameraUsageDescription</key>
    <string>Allowing access to the camera lets you take photos and videos.</string>
<key>NSMicrophoneUsageDescription</key>
    <string>Allowing access to the microphone lets you record audio.</string>

Recording Video Clips

Import the library.

import NextLevel

Setup the camera preview.

let screenBounds = UIScreen.main.bounds
self.previewView = UIView(frame: screenBounds)
if let previewView = self.previewView {
    previewView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    previewView.backgroundColor = UIColor.black
    NextLevel.shared.previewLayer.frame = previewView.bounds
    previewView.layer.addSublayer(NextLevel.shared.previewLayer)
    self.view.addSubview(previewView)
}

Configure the capture session.

override func viewDidLoad() {
    NextLevel.shared.delegate = self
    NextLevel.shared.deviceDelegate = self
    NextLevel.shared.videoDelegate = self
    NextLevel.shared.photoDelegate = self

    // modify .videoConfiguration, .audioConfiguration, .photoConfiguration properties
    // Compression, resolution, and maximum recording time options are available
    NextLevel.shared.videoConfiguration.maximumCaptureDuration = CMTimeMakeWithSeconds(5, 600)
    NextLevel.shared.audioConfiguration.bitRate = 44000
 }

Start/stop the session when appropriate. These methods create a new "session" instance for 'NextLevel.shared.session' when called.

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)     
    NextLevel.shared.start()
    // …
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)        
    NextLevel.shared.stop()
    // …
}

Video record/pause.

// record
NextLevel.shared.record()

// pause
NextLevel.shared.pause()

Editing Recorded Clips

Editing and finalizing the recorded session.

if let session = NextLevel.shared.session {

    //..

    // undo
    session.removeLastClip()

    // various editing operations can be done using the NextLevelSession methods

    // export
    session.mergeClips(usingPreset: AVAssetExportPresetHighestQuality, completionHandler: { (url: URL?, error: Error?) in
        if let _ = url {
            //
        } else if let _ = error {
            //
        }
     })

    //..

}

Videos can also be processed using the NextLevelSessionExporter, a media transcoding library in Swift.

Custom Buffer Rendering

‘NextLevel’ was designed for sample buffer analysis and custom modification in real-time along side a rich set of camera features.

Just to note, modifications performed on a buffer and provided back to NextLevel may potentially effect frame rate.

Enable custom rendering.

NextLevel.shared.isVideoCustomContextRenderingEnabled = true

Optional hook that allows reading sampleBuffer for analysis.

extension CameraViewController: NextLevelVideoDelegate {

    // ...

    // video frame processing
    public func nextLevel(_ nextLevel: NextLevel, willProcessRawVideoSampleBuffer sampleBuffer: CMSampleBuffer) {
        // Use the sampleBuffer parameter in your system for continual analysis
    }

Another optional hook for reading buffers for modification, imageBuffer. This is also the recommended place to provide the buffer back to NextLevel for recording.

extension CameraViewController: NextLevelVideoDelegate {

    // ...

    // enabled by isCustomContextVideoRenderingEnabled
    public func nextLevel(_ nextLevel: NextLevel, renderToCustomContextWithImageBuffer imageBuffer: CVPixelBuffer, onQueue queue: DispatchQueue) {
		    // provide the frame back to NextLevel for recording
        if let frame = self._availableFrameBuffer {
            nextLevel.videoCustomContextImageBuffer = frame
        }
    }

NextLevel will check this property when writing buffers to a destination file. This works for both video and photos with capturePhotoFromVideo.

nextLevel.videoCustomContextImageBuffer = modifiedFrame

About

NextLevel was initally a weekend project that has now grown into a open community of camera platform enthusists. The software provides foundational components for managing media recording, camera interface customization, gestural interaction customization, and image streaming on iOS. The same capabilities can also be found in apps such as Snapchat, Instagram, and Vine.

The goal is to continue to provide a good foundation for quick integration (enabling projects to be taken to the next level) – allowing focus to placed on functionality that matters most whether it's realtime image processing, computer vision methods, augmented reality, or computational photography.

ARKit

NextLevel provides components for capturing ARKit video and photo. This enables a variety of new camera features while leveraging the existing recording capabilities and media management of NextLevel.

If you are trying to capture frames from SceneKit for ARKit recording, check out the examples project.

GitHub

https://github.com/NextLevel/NextLevel