Add Swift API for speech enhancement GTCRN models (#1989)

swift-api-examples/speech-enhancement-gtcrn.swift

@@ -0,0 +1,55 @@
+import AVFoundation
+
+extension AudioBuffer {
+  func array() -> [Float] {
+    return Array(UnsafeBufferPointer(self))
+  }
+}
+
+extension AVAudioPCMBuffer {
+  func array() -> [Float] {
+    return self.audioBufferList.pointee.mBuffers.array()
+  }
+}
+
+func run() {
+  // Please refer to
+  // https://github.com/k2-fsa/sherpa-onnx/releases/tag/speech-enhancement-models
+  // to download files used in this script
+  var config = sherpaOnnxOfflineSpeechDenoiserConfig(
+    model: sherpaOnnxOfflineSpeechDenoiserModelConfig(
+      gtcrn: sherpaOnnxOfflineSpeechDenoiserGtcrnModelConfig(model: "./gtcrn_simple.onnx"))
+  )
+
+  let sd = SherpaOnnxOfflineSpeechDenoiserWrapper(config: &config)
+
+  let fileURL: NSURL = NSURL(fileURLWithPath: "./inp_16k.wav")
+  let audioFile = try! AVAudioFile(forReading: fileURL as URL)
+
+  let audioFormat = audioFile.processingFormat
+  assert(audioFormat.sampleRate == 16000)
+  assert(audioFormat.channelCount == 1)
+  assert(audioFormat.commonFormat == AVAudioCommonFormat.pcmFormatFloat32)
+
+  let audioFrameCount = UInt32(audioFile.length)
+  let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: audioFrameCount)
+
+  try! audioFile.read(into: audioFileBuffer!)
+  let array: [Float]! = audioFileBuffer?.array()
+  let audio = sd.run(samples: array, sampleRate: Int(audioFormat.sampleRate))
+
+  let filename = "enhanced_16k.wav"
+  let ok = audio.save(filename: filename)
+  if ok == 1 {
+    print("\nSaved to:\(filename)")
+  } else {
+    print("Failed to save to \(filename)")
+  }
+}
+
+@main
+struct App {
+  static func main() {
+    run()
+  }
+}