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Next Level

Next Level is a media capture camera library for iOS written in Swift.

Build Status Pod Version Swift Version GitHub license

:clapper: Vine-like” video clip recording and editing
:framed_picture: photo capture (raw, jpeg, and from a video frame)
:point_up_2: customizable gestural interaction and user interface
:camera: dual camera, wide angle, and telephoto device support
:turtle: adjustable frame rate on supported hardware (ie fast/slow motion capture)
:mag: video zoom
white balance, focus, and exposure adjustment
:flashlight: flash and torch support
:dancing_women: mirroring support
low light boost
:dark_sunglasses: smooth auto-focus
configurable encoding and compression settings
:hammer_and_wrench: simple media capture and editing API
:cyclone: extensible API for image processing and CV
:bird: Swift 3

Quick Start

# CocoaPods
swift_version = "3.0"
pod "NextLevel", "~> 0.3.4"

# Carthage
github "nextlevel/NextLevel" ~> 0.3.4

# Swift PM
let package = Package(
    dependencies: [
        .Package(url: "", majorVersion: 0)

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


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

    <string>Allowing access to the camera lets you take photos and videos.</string>
    <string>Allowing access to the microphone lets you record audio.</string>复制代码

Recording Video Clips

Import the library.

import NextLevel复制代码

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 =
    NextLevel.shared.previewLayer.frame = previewView.bounds

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.maxRecordDuration = 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) {
    // …
override func viewWillDisappear(_ animated: Bool) {
    // …

Video record/pause.

// record

// pause

Editing Recorded Clips

Editing and finalizing the recorded session.

if let session = NextLevel.shared.session {


    // undo

    // 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复制代码

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复制代码


You can find the docs here. Documentation is generated with jazzy and hosted on GitHub-Pages.


Next Level was a little weekend project that turned into something more useful. The software provides foundational components for advanced media recording, camera interface customization, and gestural interaction customization for 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 (taking you to the next level) – allowing everyone to focus on the app functionality that matters most. My hope is the app functionality that matters most whether is be realtime image processing, computer vision methods, augmented reality, or even new cinematographic recording techniques benefit from how this library is structured.

Related Projects


NextLevel is a community – contributions and discussions are welcome!


  • Feature idea? Open an issue.
  • Found a bug? Open an issue.
  • Need help? Use Stack Overflow with the tag ’nextlevel’.
  • Questions? Use Stack Overflow with the tag 'nextlevel'.
  • Want to contribute? Submit a pull request.


If you found this project to be helpful, check out the Next Level stickers.

You can use this sign up link for a $10 credit.

If other projects have interest in providing a similar hex sticker, it conforms to the sticker standard used by several node projects.



NextLevel is available under the MIT license, see the LICENSE file for more information.

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