Add Golang API for spoken language identification. (#709)

@@ -23,4 +23,7 @@ for details.
 - [./vad-asr-paraformer](./vad-asr-paraformer) It shows how to use silero VAD + Paraformer
   for speech recognition.
 
+- [./vad-spoken-language-identification](./vad-spoken-language-identification) It shows how to use silero VAD + Whisper
+  for spoken language identification.
+
 [sherpa-onnx]: https://github.com/k2-fsa/sherpa-onnx

+module vad-spoken-language-identification
+
+go 1.12

+package main
+
+import (
+	"fmt"
+	iso639 "github.com/barbashov/iso639-3"
+	"github.com/gordonklaus/portaudio"
+	sherpa "github.com/k2-fsa/sherpa-onnx-go/sherpa_onnx"
+	"log"
+)
+
+func main() {
+	log.SetFlags(log.LstdFlags | log.Lmicroseconds)
+
+	// 1. Create VAD
+	config := sherpa.VadModelConfig{}
+
+	// Please download silero_vad.onnx from
+	// https://github.com/snakers4/silero-vad/blob/master/files/silero_vad.onnx
+
+	config.SileroVad.Model = "./silero_vad.onnx"
+	config.SileroVad.Threshold = 0.5
+	config.SileroVad.MinSilenceDuration = 0.5
+	config.SileroVad.MinSpeechDuration = 0.25
+	config.SileroVad.WindowSize = 512
+	config.SampleRate = 16000
+	config.NumThreads = 1
+	config.Provider = "cpu"
+	config.Debug = 1
+
+	var bufferSizeInSeconds float32 = 20
+
+	vad := sherpa.NewVoiceActivityDetector(&config, bufferSizeInSeconds)
+	defer sherpa.DeleteVoiceActivityDetector(vad)
+
+	// 2. Create spoken language identifier
+
+	c := sherpa.SpokenLanguageIdentificationConfig{}
+	c.Whisper.Encoder = "./sherpa-onnx-whisper-tiny/tiny-encoder.int8.onnx"
+	c.Whisper.Decoder = "./sherpa-onnx-whisper-tiny/tiny-decoder.int8.onnx"
+	c.NumThreads = 2
+	c.Debug = 1
+	c.Provider = "cpu"
+
+	slid := sherpa.NewSpokenLanguageIdentification(&c)
+	defer sherpa.DeleteSpokenLanguageIdentification(slid)
+
+	err := portaudio.Initialize()
+	if err != nil {
+		log.Fatalf("Unable to initialize portaudio: %v\n", err)
+	}
+	defer portaudio.Terminate()
+
+	default_device, err := portaudio.DefaultInputDevice()
+	if err != nil {
+		log.Fatal("Failed to get default input device: %v\n", err)
+	}
+	log.Printf("Selected default input device: %s\n", default_device.Name)
+	param := portaudio.StreamParameters{}
+	param.Input.Device = default_device
+	param.Input.Channels = 1
+	param.Input.Latency = default_device.DefaultHighInputLatency
+
+	param.SampleRate = float64(config.SampleRate)
+	param.FramesPerBuffer = 0
+	param.Flags = portaudio.ClipOff
+
+	// you can choose another value for 0.1 if you want
+	samplesPerCall := int32(param.SampleRate * 0.1) // 0.1 second
+	samples := make([]float32, samplesPerCall)
+
+	s, err := portaudio.OpenStream(param, samples)
+	if err != nil {
+		log.Fatalf("Failed to open the stream")
+	}
+
+	defer s.Close()
+	chk(s.Start())
+
+	log.Print("Started! Please speak")
+	printed := false
+
+	k := 0
+	for {
+		chk(s.Read())
+		vad.AcceptWaveform(samples)
+
+		if vad.IsSpeech() && !printed {
+			printed = true
+			log.Print("Detected speech\n")
+		}
+
+		if !vad.IsSpeech() {
+			printed = false
+		}
+
+		for !vad.IsEmpty() {
+			speechSegment := vad.Front()
+			vad.Pop()
+
+			duration := float32(len(speechSegment.Samples)) / float32(config.SampleRate)
+
+			audio := &sherpa.GeneratedAudio{}
+			audio.Samples = speechSegment.Samples
+			audio.SampleRate = config.SampleRate
+
+			// Now decode it
+			go decode(slid, audio, k)
+
+			k += 1
+
+			log.Printf("Duration: %.2f seconds\n", duration)
+		}
+	}
+
+	chk(s.Stop())
+}
+
+func decode(slid *sherpa.SpokenLanguageIdentification, audio *sherpa.GeneratedAudio, id int) {
+	stream := slid.CreateStream()
+	defer sherpa.DeleteOfflineStream(stream)
+
+	stream.AcceptWaveform(audio.SampleRate, audio.Samples)
+	result := slid.Compute(stream)
+	lang := iso639.FromPart1Code(result.Lang).Name
+	log.Printf("Detected language: %v", lang)
+
+	duration := float32(len(audio.Samples)) / float32(audio.SampleRate)
+
+	filename := fmt.Sprintf("seg-%d-%.2f-seconds-%s.wav", id, duration, lang)
+	ok := audio.Save(filename)
+	if ok {
+		log.Printf("Saved to %s", filename)
+	}
+	log.Print("----------\n")
+}
+
+func chk(err error) {
+	if err != nil {
+		panic(err)
+	}
+}

+#!/usr/bin/env bash
+
+
+if [ ! -f ./silero_vad.onnx ]; then
+  curl -SL -O https://github.com/snakers4/silero-vad/blob/master/files/silero_vad.onnx
+fi
+
+if [ ! -f ./sherpa-onnx-whisper-tiny/tiny-encoder.int8.onnx ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-whisper-tiny.tar.bz2
+  tar xvf sherpa-onnx-whisper-tiny.tar.bz2
+  rm sherpa-onnx-whisper-tiny.tar.bz2
+fi
+
+go mod tidy
+go build
+./vad-spoken-language-identification

+vad-spoken-language-identification
+

+module vad-spoken-language-identification
+
+go 1.12
+
+replace github.com/k2-fsa/sherpa-onnx-go/sherpa_onnx => ../

+/Users/fangjun/open-source/sherpa-onnx/go-api-examples/vad-spoken-language-identification/main.go
\ No newline at end of file

+/Users/fangjun/open-source/sherpa-onnx/go-api-examples/vad-spoken-language-identification/run.sh
\ No newline at end of file

@@ -783,3 +783,72 @@ func (vad *VoiceActivityDetector) Front() *SpeechSegment {
 func (vad *VoiceActivityDetector) Reset() {
 	C.SherpaOnnxVoiceActivityDetectorReset(vad.impl)
 }
+
+// Spoken language identification
+
+type SpokenLanguageIdentificationWhisperConfig struct {
+	Encoder      string
+	Decoder      string
+	TailPaddings int
+}
+
+type SpokenLanguageIdentificationConfig struct {
+	Whisper    SpokenLanguageIdentificationWhisperConfig
+	NumThreads int
+	Debug      int
+	Provider   string
+}
+
+type SpokenLanguageIdentification struct {
+	impl *C.struct_SherpaOnnxSpokenLanguageIdentification
+}
+
+type SpokenLanguageIdentificationResult struct {
+	Lang string
+}
+
+func NewSpokenLanguageIdentification(config *SpokenLanguageIdentificationConfig) *SpokenLanguageIdentification {
+	c := C.struct_SherpaOnnxSpokenLanguageIdentificationConfig{}
+
+	c.whisper.encoder = C.CString(config.Whisper.Encoder)
+	defer C.free(unsafe.Pointer(c.whisper.encoder))
+
+	c.whisper.decoder = C.CString(config.Whisper.Decoder)
+	defer C.free(unsafe.Pointer(c.whisper.decoder))
+
+	c.whisper.tail_paddings = C.int(config.Whisper.TailPaddings)
+
+	c.num_threads = C.int(config.NumThreads)
+	c.debug = C.int(config.Debug)
+
+	c.provider = C.CString(config.Provider)
+	defer C.free(unsafe.Pointer(c.provider))
+
+	slid := &SpokenLanguageIdentification{}
+	slid.impl = C.SherpaOnnxCreateSpokenLanguageIdentification(&c)
+
+	return slid
+}
+
+func DeleteSpokenLanguageIdentification(slid *SpokenLanguageIdentification) {
+	C.SherpaOnnxDestroySpokenLanguageIdentification(slid.impl)
+	slid.impl = nil
+}
+
+// The user has to invoke DeleteOfflineStream() to free the returned value
+// to avoid memory leak
+func (slid *SpokenLanguageIdentification) CreateStream() *OfflineStream {
+	stream := &OfflineStream{}
+	stream.impl = C.SherpaOnnxSpokenLanguageIdentificationCreateOfflineStream(slid.impl)
+	return stream
+}
+
+func (slid *SpokenLanguageIdentification) Compute(stream *OfflineStream) *SpokenLanguageIdentificationResult {
+	r := C.SherpaOnnxSpokenLanguageIdentificationCompute(slid.impl, stream.impl)
+	// defer C.SherpaOnnxDestroySpokenLanguageIdentificationResult(r)
+
+	ans := &SpokenLanguageIdentificationResult{}
+	ans.Lang = C.GoString(r.lang)
+
+	return ans
+}

@@ -91,7 +91,7 @@ std::string SpokenLanguageIdentificationConfig::ToString() const {
   std::ostringstream os;
 
   os << "SpokenLanguageIdentificationConfig(";
-  os << "whisper=\"" << whisper.ToString() << "\", ";
+  os << "whisper=" << whisper.ToString() << ", ";
   os << "num_threads=" << num_threads << ", ";
   os << "debug=" << (debug ? "True" : "False") << ", ";
   os << "provider=\"" << provider << "\")";