cmd/mavwaked/main.go

@@ -12,8 +12,15 @@
 // (30ms frames, 16kHz PCM) matches silero-vad's input interface exactly, so
 // swapping energy-threshold for ONNX-inference is a local change in vad.go.
 //
+// While a reply is playing the capture side is muted (half-duplex): without
+// it, Maven's own voice comes back in through the mic and she answers
+// herself. -barge-in punches one hole in that gate — sustained energy well
+// above the speaker's leak level cuts playback so he can talk over her. It is
+// off by default because the threshold is room-specific; see playback.go.
+//
 //	usage:
 //	  mavwaked                          # default ALSA device, 127.0.0.1:9100
+//	  mavwaked -barge-in                # let him interrupt her mid-reply
 //	  mavwaked -device hw:1,0 -addr 10.42.0.1:9100
 //	  mavwaked -test file.wav           # read from file, no arecord
 package main
@@ -60,6 +67,9 @@ func run(args []string) error {
 	silenceMs := flag.Int("silence-ms", defaultSilenceMs, "silence ms to end utterance")
 	maxMs := flag.Int("max-ms", defaultMaxMs, "max utterance ms")
 	testFile := flag.String("test", "", "read PCM from file instead of arecord (testing only)")
+	bargeIn := flag.Bool("barge-in", false, "cut Maven off when he talks over her (needs a room-tuned -barge-in-rms)")
+	bargeRMS := flag.Int("barge-in-rms", defaultBargeRMS, "RMS x10000 a frame must clear to count as barge-in")
+	bargeFrames := flag.Int("barge-in-frames", defaultBargeFrames, "consecutive frames over -barge-in-rms before playback is cut")
 	flag.CommandLine.Parse(args)
 
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
@@ -117,14 +127,21 @@ func run(args []string) error {
 
 	defer src.Close()
 
-	return captureLoop(ctx, src, vad, vc, *lang)
+	var barge bargeInConfig
+	if *bargeIn {
+		barge = bargeInConfig{RMS: float64(*bargeRMS) / 10000.0, Frames: *bargeFrames}
+		log.Printf("mavwaked: barge-in on (rms %.4f x %d frames)", barge.RMS, barge.Frames)
+	}
+	sess := newSession(vad, newAplayPlayer(), &voiceSender{vc: vc}, *lang, barge)
+
+	return captureLoop(ctx, src, sess)
 }
 
-// captureLoop reads PCM from src, runs VAD, and sends complete utterances to
+// captureLoop reads PCM from src and hands whole frames to the session.
-// the voice server. Returns when ctx is done or src is exhausted.
+// Returns when ctx is done or src is exhausted.
-func captureLoop(ctx context.Context, src io.Reader, vad *VAD, vc *voice.Client, lang string) error {
+func captureLoop(ctx context.Context, src io.Reader, sess *session) error {
 	br := bufio.NewReaderSize(src, defaultReadSize)
-	frameBytes := vad.FrameSamples() * 2 // 480 samples × 2 bytes = 960 bytes per 30ms
+	frameBytes := sess.vad.FrameSamples() * 2 // 480 samples × 2 bytes = 960 bytes per 30ms
 
 	log.Printf("mavwaked: capture loop starting (frame=%d bytes, %dms)",
 		frameBytes, defaultFrameMs)
@@ -147,7 +164,7 @@ func captureLoop(ctx context.Context, src io.Reader, vad *VAD, vc *voice.Client,
 					// Flush partial frame.
 					partial = append(partial, buf[:n]...)
 					if len(partial) >= frameBytes {
-						if err := processFrame(partial[:frameBytes], vad, vc, lang); err != nil {
+						if err := sess.feed(ctx, partial[:frameBytes]); err != nil {
 							log.Printf("mavwaked: process frame: %v", err)
 						}
 						partial = partial[frameBytes:]
@@ -165,107 +182,31 @@ func captureLoop(ctx context.Context, src io.Reader, vad *VAD, vc *voice.Client,
 			partial = nil
 		}
 
-		if err := processFrame(full, vad, vc, lang); err != nil {
+		if err := sess.feed(ctx, full); err != nil {
 			log.Printf("mavwaked: process frame: %v", err)
 		}
 	}
 }
 
-// processFrame feeds one 30ms PCM frame to the VAD and sends any completed
+// voiceSender is the production utteranceSender: one PushToTalk round-trip
-// utterance to the voice server.
+// over the voice wire. SurfaceVoice (not the default SurfacePCClient that
-func processFrame(frame []byte, vad *VAD, vc *voice.Client, lang string) error {
+// c.PushToTalk uses) caps everything at L0, which is what makes an accidental
-	samples := PCMToI16(frame)
+// VAD trigger safe.
-	utt, state := vad.Feed(samples)
+type voiceSender struct{ vc *voice.Client }
 
-	if state == StateSpeech {
+func (s *voiceSender) Send(ctx context.Context, utt audio.Audio, lang string) (audio.Audio, error) {
-		// Speech is in progress; nothing to send yet.
-		return nil
-	}
-
-	if utt.Bytes == nil {
-		// Still in silence, or short speech that didn't trigger.
-		return nil
-	}
-
-	// We have a complete utterance — send it to the voice server.
-	return sendUtterance(context.Background(), utt, vc, lang)
-}
-
-// sendUtterance sends audio to the voice server and plays the reply.
-func sendUtterance(ctx context.Context, utt audio.Audio, vc *voice.Client, lang string) error {
-	dur := utt.Duration()
-	log.Printf("mavwaked: utterance complete (%.2fs, %d bytes), sending...",
-		dur, len(utt.Bytes))
-
-	// Use SendRequest directly so we can set SurfaceVoice instead of the
-	// default SurfacePCClient that c.PushToTalk uses.
 	var resp voice.PushToTalkResp
-	err := vc.SendRequest(ctx, voice.MethodPushToTalk, voice.PushToTalkReq{
+	err := s.vc.SendRequest(ctx, voice.MethodPushToTalk, voice.PushToTalkReq{
 		Audio:   utt,
 		Lang:    lang,
 		Surface: voice.SurfaceVoice,
 	}, &resp)
 	if err != nil {
-		return fmt.Errorf("push-to-talk: %w", err)
+		return audio.Audio{}, fmt.Errorf("push-to-talk: %w", err)
 	}
-
 	log.Printf("mavwaked: reply: %q (%.2fs audio)", resp.ReplyText, resp.ReplyAudio.Duration())
-
-	// Play the reply audio.
-	if len(resp.ReplyAudio.Bytes) > 0 {
-		go playAudio(resp.ReplyAudio)
-	} else {
-		log.Printf("mavwaked: empty reply audio (text only)")
-	}
-
 	if len(resp.RoutedChannels) > 0 {
 		log.Printf("mavwaked: also routed to: %v", resp.RoutedChannels)
 	}
-
+	return resp.ReplyAudio, nil
-	return nil
-}
-
-// playAudio pipes PCM audio to aplay(1) for playback. Runs in a goroutine.
-func playAudio(a audio.Audio) {
-	// Build WAV header for aplay (or pipe raw PCM with the right format flags).
-	cmd := exec.Command("aplay",
-		"-f", "S16_LE",
-		"-r", fmt.Sprintf("%d", a.Format.SampleRate),
-		"-c", fmt.Sprintf("%d", a.Format.Channels),
-		"-t", "raw",
-	)
-
-	stdin, err := cmd.StdinPipe()
-	if err != nil {
-		log.Printf("mavwaked: aplay stdin pipe: %v", err)
-		return
-	}
-
-	if err := cmd.Start(); err != nil {
-		log.Printf("mavwaked: start aplay: %v", err)
-		return
-	}
-
-	// Write audio to aplay's stdin.
-	if _, err := stdin.Write(a.Bytes); err != nil {
-		log.Printf("mavwaked: write to aplay: %v", err)
-	}
-	_ = stdin.Close()
-
-	// Wait for playback to finish (with a timeout).
-	done := make(chan error, 1)
-	go func() {
-		done <- cmd.Wait()
-	}()
-
-	select {
-	case err := <-done:
-		if err != nil {
-			log.Printf("mavwaked: aplay: %v", err)
-		}
-	case <-time.After(30 * time.Second):
-		log.Printf("mavwaked: aplay timeout, killing")
-		_ = cmd.Process.Kill()
-		<-done
-	}
 }

cmd/mavwaked/playback.go

@@ -0,0 +1,139 @@
+package main
+
+// Reply playback, and the half-duplex gate around it (Vikunja #287).
+//
+// Before this, playback was `go playAudio(reply)` — fire and forget, with no
+// handle on the running aplay. Two things fell out of that, and both are
+// audible:
+//
+//  1. Self-trigger. The capture loop keeps feeding the VAD while the speaker
+//     is playing, so Maven's own reply comes back in through the mic, trips
+//     the VAD, and is sent to the daemon as a fresh utterance. She answers
+//     herself. There is no acoustic echo canceller in this pipeline, so the
+//     only correct fix is half-duplex: while she is speaking, the capture
+//     side is muted.
+//
+//  2. No barge-in. Talking over her did nothing — there was nothing to
+//     cancel, because nobody held the process handle.
+//
+// The two are the same mechanism seen from opposite sides, so they live
+// together here. Echo suppression is unconditional (it fixes a bug). Barge-in
+// is off unless -barge-in is passed, because it needs a room-specific energy
+// threshold: with no echo canceller, the only way to tell "he is talking over
+// her" from "the mic is hearing her" is that he is louder, and how much
+// louder depends on where the mic sits relative to the speaker.
+
+import (
+	"log"
+	"os/exec"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/kami/maven/internal/audio"
+)
+
+// player plays one reply at a time and can be cut off mid-utterance.
+type player interface {
+	// Play starts playback of a, replacing anything already playing, and
+	// returns immediately.
+	Play(a audio.Audio)
+	// Stop ends playback now. A no-op when nothing is playing.
+	Stop()
+	// Playing reports whether audio is currently going out of the speaker.
+	Playing() bool
+}
+
+// aplayPlayer pipes raw PCM to aplay(1). Stop kills the child, which is what
+// makes barge-in instant rather than "instant at the end of the sentence".
+type aplayPlayer struct {
+	mu      sync.Mutex
+	cmd     *exec.Cmd
+	playing bool
+	// gen rises on every Play/Stop so a finishing playback cannot clear the
+	// playing flag of the one that replaced it.
+	gen uint64
+}
+
+func newAplayPlayer() *aplayPlayer { return &aplayPlayer{} }
+
+func (p *aplayPlayer) Play(a audio.Audio) {
+	if len(a.Bytes) == 0 {
+		return
+	}
+	p.Stop()
+
+	cmd := exec.Command("aplay",
+		"-f", "S16_LE",
+		"-r", strconv.Itoa(a.Format.SampleRate),
+		"-c", strconv.Itoa(a.Format.Channels),
+		"-t", "raw",
+	)
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		log.Printf("mavwaked: aplay stdin pipe: %v", err)
+		return
+	}
+	if err := cmd.Start(); err != nil {
+		log.Printf("mavwaked: start aplay: %v", err)
+		_ = stdin.Close()
+		return
+	}
+
+	p.mu.Lock()
+	p.gen++
+	gen := p.gen
+	p.cmd = cmd
+	p.playing = true
+	p.mu.Unlock()
+
+	go func() {
+		if _, err := stdin.Write(a.Bytes); err != nil {
+			// Broken pipe is the expected outcome of Stop().
+			log.Printf("mavwaked: write to aplay: %v", err)
+		}
+		_ = stdin.Close()
+
+		done := make(chan error, 1)
+		go func() { done <- cmd.Wait() }()
+		select {
+		case err := <-done:
+			if err != nil {
+				log.Printf("mavwaked: aplay: %v", err)
+			}
+		case <-time.After(30 * time.Second):
+			log.Printf("mavwaked: aplay timeout, killing")
+			if pr := cmd.Process; pr != nil {
+				_ = pr.Kill()
+			}
+			<-done
+		}
+
+		p.mu.Lock()
+		if p.gen == gen {
+			p.playing = false
+			p.cmd = nil
+		}
+		p.mu.Unlock()
+	}()
+}
+
+func (p *aplayPlayer) Stop() {
+	p.mu.Lock()
+	cmd := p.cmd
+	if cmd != nil {
+		p.gen++
+		p.playing = false
+		p.cmd = nil
+	}
+	p.mu.Unlock()
+	if cmd != nil && cmd.Process != nil {
+		_ = cmd.Process.Kill()
+	}
+}
+
+func (p *aplayPlayer) Playing() bool {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return p.playing
+}

cmd/mavwaked/playback_test.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/kami/maven/internal/audio"
+)
+
+// The real player must be safe to poke when nothing is playing — the capture
+// loop calls Playing() on every 30ms frame, and Stop() lands on an idle
+// player whenever a barge-in races the end of a reply. Neither may need
+// aplay(1) to be installed.
+func TestAplayPlayerIdleIsSafe(t *testing.T) {
+	p := newAplayPlayer()
+	if p.Playing() {
+		t.Fatal("a fresh player reports playing")
+	}
+	p.Stop()
+	p.Stop()
+	if p.Playing() {
+		t.Fatal("playing after Stop on an idle player")
+	}
+	// Empty audio is a text-only turn: nothing to play, no process to spawn.
+	p.Play(audio.Audio{Format: audio.PCM16kMono})
+	if p.Playing() {
+		t.Fatal("empty audio started playback")
+	}
+}
+
+func TestAplayPlayerSatisfiesPlayer(t *testing.T) {
+	var _ player = newAplayPlayer()
+	var _ player = &fakePlayer{}
+}

cmd/mavwaked/session.go

@@ -0,0 +1,123 @@
+package main
+
+// The capture session: what happens to one 30ms frame, given whether Maven is
+// currently speaking. Split out of main.go's processFrame so the decision is
+// testable without a mic, a speaker, or a daemon (Vikunja #287).
+
+import (
+	"context"
+	"log"
+
+	"github.com/kami/maven/internal/audio"
+)
+
+// utteranceSender ships one complete utterance to the voice server and
+// returns the reply audio to play. The real one round-trips over the voice
+// wire; tests substitute a recorder.
+type utteranceSender interface {
+	Send(ctx context.Context, utt audio.Audio, lang string) (audio.Audio, error)
+}
+
+// bargeInConfig holds the two numbers barge-in needs. Zero Frames disables
+// barge-in entirely — the half-duplex gate still runs.
+type bargeInConfig struct {
+	// RMS is the normalised energy a frame must exceed to count as him
+	// talking over her rather than the mic hearing her. It is deliberately
+	// far above the VAD's own floor: the speaker leaks into the mic at
+	// roughly ambient level, a person talking at the mic does not.
+	RMS float64
+	// Frames is how many consecutive frames must clear RMS before playback
+	// is cut. One loud frame is a door closing; five in a row is a voice.
+	Frames int
+}
+
+// Enabled reports whether barge-in should be attempted at all.
+func (c bargeInConfig) Enabled() bool { return c.Frames > 0 && c.RMS > 0 }
+
+// session is the per-client capture state machine.
+type session struct {
+	vad    *VAD
+	player player
+	sender utteranceSender
+	lang   string
+	barge  bargeInConfig
+
+	// loudFrames counts consecutive over-threshold frames seen while she is
+	// speaking. Reset whenever a frame falls back under the threshold, and
+	// whenever playback ends.
+	loudFrames int
+
+	// counters, read by tests and logged on the way out.
+	suppressed int // frames dropped because she was speaking
+	bargeIns   int // times playback was cut because he spoke over her
+	sent       int // utterances shipped to the daemon
+}
+
+func newSession(vad *VAD, p player, s utteranceSender, lang string, barge bargeInConfig) *session {
+	return &session{vad: vad, player: p, sender: s, lang: lang, barge: barge}
+}
+
+// feed processes one 30ms PCM frame.
+//
+// While the player is running the capture side is muted: the VAD is not fed
+// and no utterance can be produced, so Maven's own reply cannot come back in
+// as a new command. The one thing that gets through is barge-in — sustained
+// energy well above the speaker's leak level cuts playback, and capture
+// resumes on the very next frame with a clean VAD.
+func (s *session) feed(ctx context.Context, frame []byte) error {
+	if s.player.Playing() {
+		s.suppressed++
+		if !s.barge.Enabled() {
+			return nil
+		}
+		if frameRMS(PCMToI16(frame)) < s.barge.RMS {
+			s.loudFrames = 0
+			return nil
+		}
+		s.loudFrames++
+		if s.loudFrames < s.barge.Frames {
+			return nil
+		}
+		// He is talking over her. Cut her off, drop the VAD state that
+		// accumulated from the echo, and start listening for real.
+		s.player.Stop()
+		s.bargeIns++
+		s.loudFrames = 0
+		s.vad.Reset()
+		log.Printf("mavwaked: barge-in — stopped playback")
+		return nil
+	}
+
+	// Not speaking. If we just stopped, make sure no echo-era state leaks
+	// into the next utterance.
+	if s.loudFrames != 0 {
+		s.loudFrames = 0
+		s.vad.Reset()
+	}
+
+	utt, state := s.vad.Feed(PCMToI16(frame))
+	if state == StateSpeech || utt.Bytes == nil {
+		return nil
+	}
+	return s.dispatch(ctx, utt)
+}
+
+// dispatch ships a complete utterance and plays whatever comes back.
+func (s *session) dispatch(ctx context.Context, utt audio.Audio) error {
+	log.Printf("mavwaked: utterance complete (%.2fs, %d bytes), sending...", utt.Duration(), len(utt.Bytes))
+	reply, err := s.sender.Send(ctx, utt, s.lang)
+	s.sent++
+	if err != nil {
+		return err
+	}
+	if len(reply.Bytes) == 0 {
+		log.Printf("mavwaked: empty reply audio (text only)")
+		return nil
+	}
+	// The VAD has been accumulating from the buffered mic stream while the
+	// round-trip blocked. None of it is a command — reset before the
+	// speaker opens, so the first post-reply frame starts clean.
+	s.vad.Reset()
+	s.player.Play(reply)
+	return nil
+}

cmd/mavwaked/session_test.go

@@ -0,0 +1,282 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"math"
+	"testing"
+
+	"github.com/kami/maven/internal/audio"
+)
+
+// fakePlayer records Play/Stop instead of shelling out to aplay.
+type fakePlayer struct {
+	playing bool
+	plays   int
+	stops   int
+	last    audio.Audio
+}
+
+func (p *fakePlayer) Play(a audio.Audio) { p.playing = true; p.plays++; p.last = a }
+func (p *fakePlayer) Stop()              { p.playing = false; p.stops++ }
+func (p *fakePlayer) Playing() bool      { return p.playing }
+
+// fakeSender records what was shipped and hands back a canned reply.
+type fakeSender struct {
+	sent  []audio.Audio
+	reply audio.Audio
+	err   error
+}
+
+func (s *fakeSender) Send(_ context.Context, utt audio.Audio, _ string) (audio.Audio, error) {
+	s.sent = append(s.sent, utt)
+	return s.reply, s.err
+}
+
+func replyAudio() audio.Audio {
+	return audio.Audio{Format: audio.PCM16kMono, Bytes: make([]byte, 16000)}
+}
+
+// frameAt returns a 30ms frame whose RMS is approximately rms.
+func frameAt(rms float64) []byte {
+	amp := rms * math.Sqrt2 * 32768
+	f := make([]int16, frameSamples)
+	for i := range f {
+		f[i] = int16(amp * math.Sin(2*math.Pi*440*float64(i)/16000))
+	}
+	return pcmBytes(f)
+}
+
+func silentBytes() []byte { return make([]byte, frameSamples*2) }
+
+// newTestSession wires a session with fakes and a default VAD.
+func newTestSession(barge bargeInConfig) (*session, *fakePlayer, *fakeSender) {
+	p := &fakePlayer{}
+	s := &fakeSender{reply: replyAudio()}
+	return newSession(NewVAD(0, 0, 0, 0), p, s, "ru", barge), p, s
+}
+
+// speakThenPause drives a full utterance through the session: enough loud
+// frames to trigger, then enough silence to end it.
+func speakThenPause(t *testing.T, sess *session) {
+	t.Helper()
+	speechFrames := (defaultSpeechMs + defaultFrameMs - 1) / defaultFrameMs
+	silenceFrames := (defaultSilenceMs+defaultFrameMs-1)/defaultFrameMs + 2
+	loud := frameAt(0.35)
+	for i := 0; i < speechFrames+5; i++ {
+		if err := sess.feed(context.Background(), loud); err != nil {
+			t.Fatalf("feed loud frame %d: %v", i, err)
+		}
+	}
+	for i := 0; i < silenceFrames; i++ {
+		if err := sess.feed(context.Background(), silentBytes()); err != nil {
+			t.Fatalf("feed silent frame %d: %v", i, err)
+		}
+	}
+}
+
+func TestSessionSendsUtteranceAndPlaysReply(t *testing.T) {
+	sess, p, snd := newTestSession(bargeInConfig{})
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 1 {
+		t.Fatalf("sent %d utterances, want 1", len(snd.sent))
+	}
+	if snd.sent[0].Format != audio.PCM16kMono {
+		t.Errorf("utterance format = %+v, want canonical", snd.sent[0].Format)
+	}
+	if p.plays != 1 {
+		t.Errorf("plays = %d, want 1", p.plays)
+	}
+}
+
+// The bug this whole file exists for: while the speaker is running, the mic
+// hears Maven and the old code shipped that back as a fresh command.
+func TestSessionDoesNotHearItselfWhilePlaying(t *testing.T) {
+	sess, p, snd := newTestSession(bargeInConfig{})
+	speakThenPause(t, sess)
+	if !p.Playing() {
+		t.Fatal("expected playback to be running after the reply")
+	}
+
+	// Feed a long stretch of loud audio — Maven's own voice coming back in.
+	base := sess.suppressed
+	loud := frameAt(0.35)
+	for i := 0; i < 200; i++ {
+		if err := sess.feed(context.Background(), loud); err != nil {
+			t.Fatalf("feed echo frame %d: %v", i, err)
+		}
+	}
+
+	if len(snd.sent) != 1 {
+		t.Fatalf("sent %d utterances, want 1 — her own reply was captured as a command", len(snd.sent))
+	}
+	if got := sess.suppressed - base; got != 200 {
+		t.Errorf("suppressed %d of the 200 echo frames, want all of them", got)
+	}
+	if p.stops != 0 {
+		t.Errorf("stops = %d, want 0 — barge-in is off, nothing should cut her off", p.stops)
+	}
+}
+
+// With barge-in off, no amount of noise stops playback.
+func TestSessionBargeInDisabledByDefault(t *testing.T) {
+	sess, p, _ := newTestSession(bargeInConfig{})
+	if sess.barge.Enabled() {
+		t.Fatal("zero bargeInConfig must be disabled")
+	}
+	speakThenPause(t, sess)
+	veryLoud := frameAt(0.6)
+	for i := 0; i < 50; i++ {
+		_ = sess.feed(context.Background(), veryLoud)
+	}
+	if p.stops != 0 || sess.bargeIns != 0 {
+		t.Fatalf("stops = %d, bargeIns = %d, want 0 with barge-in off", p.stops, sess.bargeIns)
+	}
+}
+
+func TestSessionBargeInCutsPlayback(t *testing.T) {
+	barge := bargeInConfig{RMS: 0.12, Frames: 5}
+	sess, p, _ := newTestSession(barge)
+	speakThenPause(t, sess)
+	if !p.Playing() {
+		t.Fatal("expected playback after the reply")
+	}
+
+	// Four loud frames must not be enough — a door closing is not a voice.
+	veryLoud := frameAt(0.35)
+	for i := 0; i < 4; i++ {
+		_ = sess.feed(context.Background(), veryLoud)
+	}
+	if p.stops != 0 {
+		t.Fatalf("playback cut after 4 frames, want it to hold until %d", barge.Frames)
+	}
+
+	// The fifth cuts her off.
+	_ = sess.feed(context.Background(), veryLoud)
+	if p.stops != 1 || sess.bargeIns != 1 {
+		t.Fatalf("stops = %d, bargeIns = %d, want 1 and 1", p.stops, sess.bargeIns)
+	}
+	if p.Playing() {
+		t.Fatal("still playing after barge-in")
+	}
+}
+
+// A burst that falls back under the threshold resets the counter, so noise
+// spread over a whole reply never accumulates into a false barge-in.
+func TestSessionBargeInNeedsConsecutiveFrames(t *testing.T) {
+	sess, p, _ := newTestSession(bargeInConfig{RMS: 0.12, Frames: 5})
+	speakThenPause(t, sess)
+
+	veryLoud := frameAt(0.35)
+	quiet := frameAt(0.02)
+	for i := 0; i < 20; i++ {
+		_ = sess.feed(context.Background(), veryLoud)
+		_ = sess.feed(context.Background(), veryLoud)
+		_ = sess.feed(context.Background(), quiet)
+	}
+	if p.stops != 0 || sess.bargeIns != 0 {
+		t.Fatalf("stops = %d, bargeIns = %d, want 0 — two-frame bursts must not accumulate", p.stops, sess.bargeIns)
+	}
+}
+
+// Speaker leak sits near the room floor; it must never reach the barge-in bar.
+func TestSessionEchoLevelAudioNeverBargesIn(t *testing.T) {
+	sess, p, _ := newTestSession(bargeInConfig{RMS: 0.12, Frames: 5})
+	speakThenPause(t, sess)
+
+	base := sess.suppressed
+	leak := frameAt(0.05) // loud enough for the VAD, far under the barge bar
+	for i := 0; i < 300; i++ {
+		_ = sess.feed(context.Background(), leak)
+	}
+	if p.stops != 0 {
+		t.Fatalf("stops = %d, want 0 — speaker leak must not read as barge-in", p.stops)
+	}
+	if got := sess.suppressed - base; got != 300 {
+		t.Errorf("suppressed %d of the 300 leak frames, want all of them", got)
+	}
+}
+
+// After barge-in the VAD must start clean, so the interrupting speech is
+// captured as a whole utterance rather than joined onto echo state.
+func TestSessionCapturesTheInterruptingUtterance(t *testing.T) {
+	sess, p, snd := newTestSession(bargeInConfig{RMS: 0.12, Frames: 5})
+	speakThenPause(t, sess)
+
+	veryLoud := frameAt(0.35)
+	for i := 0; i < 5; i++ {
+		_ = sess.feed(context.Background(), veryLoud)
+	}
+	if p.stops != 1 {
+		t.Fatalf("expected barge-in, stops = %d", p.stops)
+	}
+
+	// He keeps talking; that is a new command.
+	speakThenPause(t, sess)
+	if len(snd.sent) != 2 {
+		t.Fatalf("sent %d utterances, want 2 — the interruption itself must be heard", len(snd.sent))
+	}
+	if p.plays != 2 {
+		t.Errorf("plays = %d, want 2", p.plays)
+	}
+}
+
+// A failed round-trip must surface as an error and must not start playback.
+func TestSessionSendErrorDoesNotPlay(t *testing.T) {
+	p := &fakePlayer{}
+	snd := &fakeSender{err: errors.New("boom")}
+	sess := newSession(NewVAD(0, 0, 0, 0), p, snd, "ru", bargeInConfig{})
+
+	speechFrames := (defaultSpeechMs + defaultFrameMs - 1) / defaultFrameMs
+	silenceFrames := (defaultSilenceMs+defaultFrameMs-1)/defaultFrameMs + 2
+	loud := frameAt(0.35)
+	var lastErr error
+	for i := 0; i < speechFrames+5; i++ {
+		_ = sess.feed(context.Background(), loud)
+	}
+	for i := 0; i < silenceFrames; i++ {
+		if err := sess.feed(context.Background(), silentBytes()); err != nil {
+			lastErr = err
+		}
+	}
+	if lastErr == nil {
+		t.Fatal("send error was swallowed")
+	}
+	if p.plays != 0 || p.Playing() {
+		t.Fatalf("plays = %d, playing = %v, want no playback on a failed round-trip", p.plays, p.Playing())
+	}
+}
+
+// An empty reply (text-only turn) must leave the capture side open.
+func TestSessionEmptyReplyLeavesCaptureOpen(t *testing.T) {
+	p := &fakePlayer{}
+	snd := &fakeSender{reply: audio.Audio{Format: audio.PCM16kMono}}
+	sess := newSession(NewVAD(0, 0, 0, 0), p, snd, "ru", bargeInConfig{})
+
+	speakThenPause(t, sess)
+	if p.plays != 0 {
+		t.Fatalf("plays = %d, want 0 for an empty reply", p.plays)
+	}
+	speakThenPause(t, sess)
+	if len(snd.sent) != 2 {
+		t.Fatalf("sent %d, want 2 — capture must stay open when there is no audio reply", len(snd.sent))
+	}
+}
+
+func TestBargeInConfigEnabled(t *testing.T) {
+	cases := []struct {
+		c    bargeInConfig
+		want bool
+	}{
+		{bargeInConfig{}, false},
+		{bargeInConfig{RMS: 0.12}, false},
+		{bargeInConfig{Frames: 5}, false},
+		{bargeInConfig{RMS: 0.12, Frames: 5}, true},
+	}
+	for _, tc := range cases {
+		if got := tc.c.Enabled(); got != tc.want {
+			t.Errorf("%+v.Enabled() = %v, want %v", tc.c, got, tc.want)
+		}
+	}
+}

cmd/mavwaked/vad.go

@@ -23,6 +23,15 @@ const (
 	defaultSilenceMs = 800   // silence hold before declaring end-of-utterance
 	defaultMaxMs     = 10000 // cap single utterance at 10s
 	defaultMinRMS    = 0.01  // RMS floor (same as mavsttd)
+
+	// Barge-in thresholds. Only used when -barge-in is passed. The RMS is
+	// x10000 like -min-rms, and sits an order of magnitude above the VAD's
+	// own floor on purpose: with no acoustic echo canceller, a frame only
+	// counts as "he is talking over her" if it is far louder than what the
+	// speaker leaks back into the mic. 5 frames is 150ms — long enough that
+	// a door or a cough does not cut her off mid-sentence.
+	defaultBargeRMS    = 1200 // 0.12 normalised RMS
+	defaultBargeFrames = 5
 )
 
 // frameSamples — samples per 30ms frame at 16kHz.