AVFoundation for Swift: Complete Guide with Examples

Introduction to AVFoundation

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AVFoundation is a powerful framework from Apple designed for working with audio and video on iOS, macOS, tvOS, and watchOS platforms. It provides developers with a high-level API for capturing, processing, playing back, and editing multimedia content. Unlike lower-level solutions (such as Core Audio or Video Toolbox), AVFoundation abstracts the complex details of codecs, containers, and synchronization, allowing you to focus on application logic.

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Why do you need AVFoundation? It enables solving a wide range of tasks:

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• Playback: Playing audio files (MP3, AAC, WAV) and video files (MP4, MOV, M4V) with support for subtitles and chapters.
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• Recording: Capturing video from the camera and audio from the microphone in real time.
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• Editing: Creating compositions from multiple tracks, applying effects, trimming, changing speed.
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• Processing: Extracting metadata, working with audio samples, applying filters.
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• Streaming: Playing HLS (HTTP Live Streaming) content.
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AVFoundation is the de facto standard for Apple development. If you are writing an application that needs to play music, record video, or edit podcasts — you will be using this framework.

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Installation (Adding to Project)

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AVFoundation is not installed via pip or npm, as it is a native Apple framework. It is built into Xcode and the SDK. To use it, simply import the module into your Swift files.

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Steps to add:

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1. Open your project in Xcode.
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2. In any Swift file where you need to work with multimedia, add the import statement:
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import AVFoundation

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No additional actions are required. The framework is automatically available for all iOS/macOS projects.

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Configuring Permissions (iOS)

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To work with the camera and microphone, you need to add entries to the Info.plist file:

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• NSCameraUsageDescription — description of why the app needs the camera.
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• NSMicrophoneUsageDescription — description of why the app needs the microphone.
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Without these keys, the app will crash with an error when attempting to access the devices.

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Quick Start: Playing Audio

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The simplest example is playing a local audio file. Create an instance of AVAudioPlayer and call the play() method.

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import AVFoundation\nimport UIKit\n\nclass ViewController: UIViewController {\n    var audioPlayer: AVAudioPlayer?\n\n    override func viewDidLoad() {\n        super.viewDidLoad()\n        \n        // 1. Find the file path in the Bundle\n        guard let path = Bundle.main.path(forResource: "sample", ofType: "mp3") else {\n            print("File not found")\n            return\n        }\n        \n        let url = URL(fileURLWithPath: path)\n        \n        do {\n            // 2. Initialize the player\n            audioPlayer = try AVAudioPlayer(contentsOf: url)\n            // 3. Prepare for playback (optional but recommended)\n            audioPlayer?.prepareToPlay()\n            // 4. Start playing\n            audioPlayer?.play()\n            print("Playback started")\n        } catch {\n            print("Player initialization error: \\(error.localizedDescription)")\n        }\n    }\n}

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This code creates a player, loads the sample.mp3 file from the app's resources, and starts playing it.

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Key Classes and Methods

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Below are the key AVFoundation classes and methods used in 90% of tasks. For each method, a description, parameters, and a working example are provided.

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1. AVAudioPlayer

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What