Swift API for keyword spotting. (#1027)

swift-api-examples/keyword-spotting-from-file.swift

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+import AVFoundation
+
+extension AudioBuffer {
+  func array() -> [Float] {
+    return Array(UnsafeBufferPointer(self))
+  }
+}
+
+extension AVAudioPCMBuffer {
+  func array() -> [Float] {
+    return self.audioBufferList.pointee.mBuffers.array()
+  }
+}
+
+func run() {
+  let filePath = "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/test_wavs/3.wav"
+  let encoder =
+    "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/encoder-epoch-12-avg-2-chunk-16-left-64.onnx"
+  let decoder =
+    "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/decoder-epoch-12-avg-2-chunk-16-left-64.onnx"
+  let joiner =
+    "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/joiner-epoch-12-avg-2-chunk-16-left-64.onnx"
+  let tokens =
+    "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/tokens.txt"
+  let keywordsFile =
+    "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/test_wavs/test_keywords.txt"
+  let transducerConfig = sherpaOnnxOnlineTransducerModelConfig(
+    encoder: encoder,
+    decoder: decoder,
+    joiner: joiner
+  )
+
+  let modelConfig = sherpaOnnxOnlineModelConfig(
+    tokens: tokens,
+    transducer: transducerConfig
+  )
+
+  let featConfig = sherpaOnnxFeatureConfig(
+    sampleRate: 16000,
+    featureDim: 80
+  )
+  var config = sherpaOnnxKeywordSpotterConfig(
+    featConfig: featConfig,
+    modelConfig: modelConfig,
+    keywordsFile: keywordsFile
+  )
+
+  let spotter = SherpaOnnxKeywordSpotterWrapper(config: &config)
+
+  let fileURL: NSURL = NSURL(fileURLWithPath: filePath)
+  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()
+  spotter.acceptWaveform(samples: array)
+
+  let tailPadding = [Float](repeating: 0.0, count: 3200)
+  spotter.acceptWaveform(samples: tailPadding)
+
+  spotter.inputFinished()
+  while spotter.isReady() {
+    spotter.decode()
+    let keyword = spotter.getResult().keyword
+    if keyword != "" {
+      print("Detected: \(keyword)")
+    }
+  }
+}
+
+@main
+struct App {
+  static func main() {
+    run()
+  }
+}