Rubber Band Library – iOS & macOS AVFoundation Example

This project demonstrates how to integrate the Rubber Band Library into an iOS or macOS application using AVFoundation. It includes a working Objective-C example that loads an audio file, applies real-time pitch and time-stretching using Rubber Band, and plays back the processed audio.

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🔧 Features

• ✅ Real-time audio pitch shifting
• ✅ Optional time-stretching
• ✅ Uses Rubber Band v4.0.0 (R3 engine support)
• ✅ Formant preservation for natural voice quality
• ✅ Built with AVAudioEngine and AVAudioPlayerNode

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📦 Requirements

• Xcode 14 or newer
• iOS 14+ or macOS 11+

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🚀 Setup Instructions

1. Clone this repo

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🧠 Key Concepts

• Rubber Band requires audio to be de-interleaved per channel
• Audio is processed in blocks and output is reassembled into buffers
• The R3 engine (OptionEngineFiner) provides higher-quality pitch shifting
• OptionFormantPreserved maintains vocal character

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🙌 Credits

• Rubber Band Library by Particular Programs Ltd.
• Example developed by Jerry Seigle

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📄 License

This example is for educational purposes and provided "as-is." For commercial use of the Rubber Band Library, you must obtain a license from the authors.

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