Add VAD configuration and implement VAD reader for audio processing

config.yaml

@@ -1,3 +1,5 @@
 rtsp_url: "rtsp://10.10.10.104:8554/union"
 output_file: "output.wav"
 record_segment_duration: "30m"  # Duration for each recording segment
+vad_mode: 1
+frame_ms: 10

go.mod

@@ -5,6 +5,7 @@ go 1.25
 require (
 	github.com/bluenviron/gortsplib/v4 v4.16.2
 	github.com/bluenviron/mediacommon/v2 v2.4.1
+	github.com/maxhawkins/go-webrtcvad v0.0.0-20210121163624-be60036f3083
 	github.com/pion/rtp v1.8.21
 	gopkg.in/yaml.v3 v3.0.1
 )

go.sum

@@ -6,6 +6,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/maxhawkins/go-webrtcvad v0.0.0-20210121163624-be60036f3083 h1:0JDcvP4R28p6+u8VIHCwYx7UwiHZ074INz3C397oc9s=
+github.com/maxhawkins/go-webrtcvad v0.0.0-20210121163624-be60036f3083/go.mod h1:YdrZ05xnooeP54y7m+/UvI23O1Td46PjWkLJu1VLObM=
 github.com/pion/logging v0.2.4 h1:tTew+7cmQ+Mc1pTBLKH2puKsOvhm32dROumOZ655zB8=
 github.com/pion/logging v0.2.4/go.mod h1:DffhXTKYdNZU+KtJ5pyQDjvOAh/GsNSyv1lbkFbe3so=
 github.com/pion/randutil v0.1.0 h1:CFG1UdESneORglEsnimhUjf33Rwjubwj6xfiOXBa3mA=

main.go

@@ -16,15 +16,18 @@ import (
 	"github.com/bluenviron/gortsplib/v4/pkg/description"
 	"github.com/bluenviron/gortsplib/v4/pkg/format"
 	"github.com/bluenviron/mediacommon/v2/pkg/codecs/g711"
+	"github.com/maxhawkins/go-webrtcvad"
 	"github.com/pion/rtp"
 	"gopkg.in/yaml.v3"
 )
 
-// Config holds RTSP URL, output file path, and rotation settings
+// Config holds RTSP URL, output file path, rotation settings, and VAD settings
 type Config struct {
 	RTSPURL               string `yaml:"rtsp_url"`
 	OutputFile            string `yaml:"output_file"`
-	RecordSegmentDuration string `yaml:"record_segment_duration"` // Added
+	RecordSegmentDuration string `yaml:"record_segment_duration"`
+	VADMode               int    `yaml:"vad_mode"`
+	FrameMs               int    `yaml:"frame_ms"`
 }
 
 // Event represents lifecycle events (e.g., source ready, recording started)
@@ -66,6 +69,19 @@ type Recorder struct {
 	fileMu        sync.Mutex    // Protects file operations // Added
 }
 
+// VADReader detects speech in audio packets using WebRTC VAD
+type VADReader struct {
+	name         string
+	path         *Path
+	isMuLaw      bool
+	dataChan     chan *Data
+	terminate    chan struct{}
+	vad          *webrtcvad.VAD
+	sampleRate   int
+	frameMs      int
+	segmentStart time.Time // Tracks start of current audio/silence segment
+}
+
 // NewPath creates a stream hub
 func NewPath(eventChan chan Event) *Path {
 	return &Path{
@@ -341,6 +357,135 @@ func (r *Recorder) Stop() {
 	close(r.terminate)
 }
 
+// NewVADReader creates a VAD reader that subscribes to the path
+func NewVADReader(path *Path, isMuLaw bool, vadMode, frameMs int) (*VADReader, error) {
+	vad, err := webrtcvad.New()
+	if err != nil {
+		return nil, fmt.Errorf("create VAD: %w", err)
+	}
+	if err := vad.SetMode(vadMode); err != nil {
+		return nil, fmt.Errorf("set VAD mode %d: %w", vadMode, err)
+	}
+	if frameMs != 10 && frameMs != 20 && frameMs != 30 {
+		return nil, fmt.Errorf("invalid frame duration %dms; must be 10, 20, or 30", frameMs)
+	}
+	sampleRate := 8000
+	frameSamples := sampleRate * frameMs / 1000
+	frameBytes := frameSamples * 2 // 16-bit PCM
+	if !vad.ValidRateAndFrameLength(sampleRate, frameBytes) {
+		return nil, fmt.Errorf("invalid VAD parameters: sample_rate=%d, frame_bytes=%d", sampleRate, frameBytes)
+	}
+
+	r := &VADReader{
+		name:         "vad_reader",
+		path:         path,
+		isMuLaw:      isMuLaw,
+		dataChan:     make(chan *Data, 100), // Buffered channel
+		terminate:    make(chan struct{}),
+		vad:          vad,
+		sampleRate:   sampleRate,
+		frameMs:      frameMs,
+		segmentStart: time.Now(),
+	}
+	path.AddReader(r.name, r.dataChan)
+	return r, nil
+}
+
+// Start runs the VAD reader's async processing loop
+func (r *VADReader) Start() {
+	go func() {
+		var pcmBuffer []byte
+		var isSilent = true
+		var audioStart time.Time                   // Added to track audio duration
+		const minSilenceDuration = 4 * time.Second // Changed from 2s
+		const maxSilenceDuration = 6 * time.Second // Added
+
+		frameSamples := r.sampleRate * r.frameMs / 1000
+		frameBytes := frameSamples * 2 // 16-bit PCM
+		for {
+			select {
+			case data := <-r.dataChan:
+				if data.Media.Type == "audio" {
+					// Unmarshal G.711 payload
+					var samples []byte
+					var err error
+					if r.isMuLaw {
+						var mu g711.Mulaw
+						mu.Unmarshal(data.Pkt.Payload)
+						samples = []byte(mu)
+					} else {
+						var al g711.Alaw
+						al.Unmarshal(data.Pkt.Payload)
+						samples = []byte(al)
+					}
+					if err != nil {
+						slog.Error("Unmarshal audio error", "error", err)
+						continue
+					}
+					// Convert to 16-bit PCM
+					for _, sample := range samples {
+						var pcmSample int16
+						if r.isMuLaw {
+							pcmSample = muLawToPCM(sample)
+						} else {
+							pcmSample = aLawToPCM(sample)
+						}
+						var buf [2]byte
+						binary.LittleEndian.PutUint16(buf[:], uint16(pcmSample))
+						pcmBuffer = append(pcmBuffer, buf[:]...)
+					}
+
+					// Process VAD frames
+					for len(pcmBuffer) >= frameBytes {
+						frame := pcmBuffer[:frameBytes]
+						pcmBuffer = pcmBuffer[frameBytes:]
+
+						active, err := r.vad.Process(r.sampleRate, frame)
+						if err != nil {
+							slog.Warn("VAD processing error", "error", err)
+							continue
+						}
+
+						now := time.Now()
+						if active && isSilent {
+							slog.Info("Speech detected", "timestamp", now.Format("2006-01-02 15:04:05"))
+							r.path.eventChan <- Event{Type: "speech_detected", Data: now}
+							isSilent = false
+							r.segmentStart = now
+							audioStart = now // Added
+						} else if !active && !isSilent {
+							if r.segmentStart.IsZero() {
+								r.segmentStart = now
+							} else if now.Sub(r.segmentStart) >= minSilenceDuration && now.Sub(r.segmentStart) <= maxSilenceDuration {
+								var audioDurationMs int64
+								if !audioStart.IsZero() {
+									audioDurationMs = now.Sub(audioStart).Milliseconds() // Added
+								}
+								slog.Info("Silence detected",
+									"timestamp", now.Format("2006-01-02 15:04:05"),
+									"silence_duration_ms", now.Sub(r.segmentStart).Milliseconds(),
+									"audio_duration_ms", audioDurationMs) // Added
+								r.path.eventChan <- Event{Type: "silence_detected", Data: now}
+								isSilent = true
+								r.segmentStart = time.Time{} // Modified: reset to allow new silence detection
+								audioStart = time.Time{}     // Added
+							}
+						}
+					}
+				}
+			case <-r.terminate:
+				return
+			}
+		}
+	}()
+}
+
+// Stop terminates the VAD reader
+func (r *VADReader) Stop() {
+	r.path.RemoveReader(r.name)
+	close(r.terminate)
+}
+
 func main() {
 	// Initialize slog (default handler for structured logging)
 	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelInfo})))
@@ -361,6 +506,7 @@ func main() {
 		os.Exit(1)
 	}
 
+	// Parse segment duration (default to 5 minutes)
 	segmentDur := 5 * time.Minute
 	if conf.RecordSegmentDuration != "" {
 		dur, err := time.ParseDuration(conf.RecordSegmentDuration)
@@ -371,6 +517,24 @@ func main() {
 		segmentDur = dur
 	}
 
+	// Parse VAD settings (default: mode=3, frame_ms=20)
+	vadMode := 3
+	frameMs := 20
+	if conf.VADMode != 0 {
+		if conf.VADMode < 0 || conf.VADMode > 3 {
+			slog.Error("Invalid vad_mode", "value", conf.VADMode, "allowed", "0-3")
+			os.Exit(1)
+		}
+		vadMode = conf.VADMode
+	}
+	if conf.FrameMs != 0 {
+		if conf.FrameMs != 10 && conf.FrameMs != 20 && conf.FrameMs != 30 {
+			slog.Error("Invalid frame_ms", "value", conf.FrameMs, "allowed", "10, 20, 30")
+			os.Exit(1)
+		}
+		frameMs = conf.FrameMs
+	}
+
 	// Step 2: Set up event bus
 	eventChan := make(chan Event, 10)
 	go func() {
@@ -436,10 +600,18 @@ func main() {
 	}
 	recorder.Start()
 
-	// Step 6: Signal source ready
+	// Step 6: Set up VAD reader
+	vadReader, err := NewVADReader(path, isMuLaw, vadMode, frameMs)
+	if err != nil {
+		slog.Error("Create VAD reader", "error", err)
+		os.Exit(1)
+	}
+	vadReader.Start()
+
+	// Step 7: Signal source ready
 	path.SourceReady(audioMedia, audioFormat)
 
-	// Step 7: Read RTP packets and distribute
+	// Step 8: Read RTP packets and distribute
 	go func() {
 		c.OnPacketRTP(audioMedia, audioFormat, func(pkt *rtp.Packet) {
 			path.DistributeData(&Data{Media: audioMedia, Pkt: pkt})