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Code samples

NCKitStreamProcessor

Live / real-time denoise adapter for AVAudioEngine microphone taps. Resamples to 48 kHz mono, accumulates 10 ms hops, and drives NCKitProcessor.processFrame.

Requires NCKit 1.1.1+ for reset().

API​

public final class NCKitStreamProcessor {
    public let frameLength: Int

    public init(processor: NCKitProcessor) throws

    public func prepare(inputFormat: AVAudioFormat) throws
    public func convertToTargetFormat(_ buffer: AVAudioPCMBuffer) throws -> AVAudioPCMBuffer
    public func process(buffer: AVAudioPCMBuffer) throws -> [AVAudioPCMBuffer]
    public func processConverted(_ buffer: AVAudioPCMBuffer) throws -> [AVAudioPCMBuffer]
    public func flush() throws -> [AVAudioPCMBuffer]
    public func reset()
    public func setAttenLim(_ db: Float)
    public func setPostFilterBeta(_ b: Float)
}

Setup​

import NCKit
import AVFoundation

let modelURL = try NCKitModelLocator.modelTarGzURL()
let processor = try NCKitProcessor(modelURL: modelURL)
let stream = try NCKitStreamProcessor(processor: processor)

Install microphone tap​

inputNode.installTap(onBus: 0, bufferSize: 4096, format: tapFormat) { buffer, _ in
    try stream.prepare(inputFormat: buffer.format)
    let frames = try stream.process(buffer: buffer)
    for frame in frames {
        // 480 Float samples @ 48 kHz mono
    }
}

Dry + denoised (A/B)​

try stream.prepare(inputFormat: buffer.format)
let dry = try stream.convertToTargetFormat(buffer)
let denoised = try stream.processConverted(dry)

End of session​

let tail = try stream.flush()
stream.reset()

Threading​

Not thread-safe — call prepare, process, processConverted, flush, and reset from one serial queue (typically the audio tap thread).