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| 1 | +import Foundation |
| 2 | +import Flutter |
| 3 | +import WhisperKit |
| 4 | + |
| 5 | +public class WhisperKitRunner: NSObject, FlutterStreamHandler { |
| 6 | + let transcriptionChannelName = "lotti/transcribe" |
| 7 | + let transcriptionProgressChannelName = "lotti/transcribe-progress" |
| 8 | + let model = "small" |
| 9 | + |
| 10 | + private var eventSink: FlutterEventSink? |
| 11 | + private let transcriptionChannel: FlutterMethodChannel |
| 12 | + private let transcriptionProgressChannel: FlutterEventChannel |
| 13 | + |
| 14 | + private var whisperKit: WhisperKit? |
| 15 | + |
| 16 | + init(binaryMessenger: FlutterBinaryMessenger) { |
| 17 | + transcriptionChannel = FlutterMethodChannel( |
| 18 | + name: transcriptionChannelName, |
| 19 | + binaryMessenger: binaryMessenger) |
| 20 | + |
| 21 | + transcriptionProgressChannel = FlutterEventChannel(name: transcriptionProgressChannelName, |
| 22 | + binaryMessenger: binaryMessenger) |
| 23 | + |
| 24 | + super.init() |
| 25 | + |
| 26 | + transcriptionChannel.setMethodCallHandler { (call, result) in |
| 27 | + switch call.method { |
| 28 | + case "transcribe": |
| 29 | + guard let args = call.arguments as? [String: Any] else { return } |
| 30 | + let audioFilePath = args["audioFilePath"] as! String |
| 31 | + |
| 32 | + Task { |
| 33 | + if (self.whisperKit == nil) { |
| 34 | + if (self.eventSink != nil) { |
| 35 | + self.eventSink!(["initializing model...", ""]) |
| 36 | + } |
| 37 | + |
| 38 | + self.whisperKit = try? await WhisperKit(model: self.model, |
| 39 | + verbose: true, |
| 40 | + prewarm: true) |
| 41 | + } |
| 42 | + |
| 43 | + let transcription = try? await self.whisperKit!.transcribe( |
| 44 | + audioPath: audioFilePath, |
| 45 | + decodeOptions: DecodingOptions( |
| 46 | + task: DecodingTask.transcribe, |
| 47 | + usePrefillPrompt: false |
| 48 | + ), |
| 49 | + callback: self.sendTranscriptionProgressEvent |
| 50 | + ) |
| 51 | + |
| 52 | + let text = transcription?.text |
| 53 | + let language = transcription?.language |
| 54 | + |
| 55 | + let data = [language, self.model, text] |
| 56 | + result(data) |
| 57 | + } |
| 58 | + default: |
| 59 | + result(FlutterMethodNotImplemented) |
| 60 | + } |
| 61 | + } |
| 62 | + |
| 63 | + transcriptionProgressChannel.setStreamHandler(self) |
| 64 | + } |
| 65 | + |
| 66 | + private func sendTranscriptionProgressEvent(progress: TranscriptionProgress)->Bool? { |
| 67 | + guard let eventSink = eventSink else { |
| 68 | + return nil |
| 69 | + } |
| 70 | + |
| 71 | + eventSink([progress.text, |
| 72 | + progress.timings.pipelineStart.formatted()]) |
| 73 | + return nil |
| 74 | + } |
| 75 | + |
| 76 | + public func onListen(withArguments arguments: Any?, |
| 77 | + eventSink: @escaping FlutterEventSink) -> FlutterError? { |
| 78 | + self.eventSink = eventSink |
| 79 | + return nil |
| 80 | + } |
| 81 | + |
| 82 | + public func onCancel(withArguments arguments: Any?) -> FlutterError? { |
| 83 | + eventSink = nil |
| 84 | + return nil |
| 85 | + } |
| 86 | +} |
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