From d0ea08852a23a234d4baea76eb0d4f276392fc1e Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 11:00:50 -0700
Subject: [PATCH 1/9] Remove audio input processor.


From 8d011d600478aa015cb6da8e4f21934de2071393 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Thu, 13 Aug 2026 16:21:10 -0700
Subject: [PATCH 2/9] Rename MediaSegment methods.

---
 pkg/sip/inbound.go                     |  8 ++++----
 pkg/sip/media_port.go                  | 24 +++++++++++++++---------
 pkg/sip/media_port_negotiation_test.go |  8 ++++----
 pkg/sip/media_port_pending_test.go     |  4 ++--
 pkg/sip/outbound.go                    | 10 +++++-----
 5 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 95fded36..0acbfcf8 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -978,7 +978,7 @@ func (c *inboundCall) handleInvite(ctx context.Context, tid traceid.ID, req *sip
 			// Start this timer right after the Accept.
 			ackTimeout = time.After(inviteOkAckLateTimeout)
 		}
-		if old := c.audioOut.Swap(c.media.GetAudioWriter()); old != nil {
+		if old := c.audioOut.Swap(c.media.GetOutboundAudioWriter()); old != nil {
 			c.log().Warnw("unexpected audio out writer", nil)
 			old.Close()
 		}
@@ -1173,13 +1173,13 @@ func (c *inboundCall) runMediaConn(tid traceid.ID, offerData []byte, mconf *sipM
 	c.mon.SDPSize(len(answerData), false)
 	c.log().Debugw("SDP answer", "sdp", string(answerData))
 
-	mp.WriteDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
+	mp.WriteInboundDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
 
 	// Must be set earlier to send the pin prompts.
 	if w := c.lkRoom.SwapOutput(c.audioOut); w != nil {
 		_ = w.Close()
 	}
-	c.lkRoom.SetDTMFOutput(c.media.GetDTMFWriter())
+	c.lkRoom.SetDTMFOutput(c.media.GetOutboundDTMFWriter())
 
 	audio := mp.NegotiatedAudio()
 	if audio == nil {
@@ -1616,7 +1616,7 @@ func (c *inboundCall) publishTrack(features []livekit.SIPFeature, featureFlags m
 	if audioInProcessor := c.s.handler.GetMediaProcessor(features, featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); audioInProcessor != nil {
 		local = audioInProcessor(local)
 	}
-	c.media.WriteAudioTo(local)
+	c.media.WriteInboundAudioTo(local)
 	return nil
 }
 
diff --git a/pkg/sip/media_port.go b/pkg/sip/media_port.go
index 64c6dee9..7ad4f180 100644
--- a/pkg/sip/media_port.go
+++ b/pkg/sip/media_port.go
@@ -391,10 +391,16 @@ func (o *MediaOptions) ApplyDefaults() {
 }
 
 type MediaSegment interface {
-	GetAudioWriter() msdk.PCM16Writer
-	WriteAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer
-	GetDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF]
-	WriteDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF]
+	// GetOutboundAudioWriter returns the LK room -> SIP writer.
+	GetOutboundAudioWriter() msdk.PCM16Writer
+	// GetOutboundDTMFWriter returns the LK room -> SIP DTMF writer.
+	GetOutboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF]
+
+	// WriteInboundAudioTo tells the MediaSegment where to write inbound SIP audio.
+	WriteInboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer
+
+	// WriteInboundDTMFTo tells the MediaSegment where to write inbound SIP DTMF.
+	WriteInboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF]
 }
 
 // MediaPort is the insulated media-plane API: UDP/RTP to the wire, SDP negotiation,
@@ -731,20 +737,20 @@ func (p *mediaPort) reportPeerCodecs(d sdp.MediaDesc) {
 
 // Plumbing
 
-func (p *mediaPort) GetAudioWriter() msdk.PCM16Writer {
+func (p *mediaPort) GetOutboundAudioWriter() msdk.PCM16Writer {
 	return p.audioOut
 }
 
-// WriteAudioTo sets audio writer that will receive decoded PCM from incoming RTP packets.
-func (p *mediaPort) WriteAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer {
+// WriteInboundAudioTo sets audio writer that will receive decoded PCM from incoming RTP packets.
+func (p *mediaPort) WriteInboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer {
 	return p.audioIn.Swap(w)
 }
 
-func (p *mediaPort) GetDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
+func (p *mediaPort) GetOutboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
 	return &p.dtmfOut
 }
 
-func (p *mediaPort) WriteDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF] {
+func (p *mediaPort) WriteInboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF] {
 	return p.dtmfIn.Swap(w)
 }
 
diff --git a/pkg/sip/media_port_negotiation_test.go b/pkg/sip/media_port_negotiation_test.go
index 5a984237..0f0a188b 100644
--- a/pkg/sip/media_port_negotiation_test.go
+++ b/pkg/sip/media_port_negotiation_test.go
@@ -169,7 +169,7 @@ func TestMediaPortRenegotiation(t *testing.T) {
 		m1, m2 := newMediaPair(t, nil, nil, "")
 
 		recv2 := &recvBuffer{}
-		m2.WriteAudioTo(recv2)
+		m2.WriteInboundAudioTo(recv2)
 		requireAudioFlows(t, m1, recv2)
 
 		for range 3 {
@@ -203,7 +203,7 @@ func TestMediaPortRenegotiation(t *testing.T) {
 		require.Equal(t, g711.ULawSDPNameAndRate, answerCodec(t, answerData))
 
 		recv2 := &recvBuffer{}
-		m2.WriteAudioTo(recv2)
+		m2.WriteInboundAudioTo(recv2)
 		requireAudioFlows(t, m1, recv2)
 
 		// G722 samples at 16k, so the encode leaf changes sample rate under the same
@@ -247,9 +247,9 @@ func TestMediaPortHold(t *testing.T) {
 			m1, m2 := newMediaPair(t, nil, nil, "")
 
 			recv1 := &recvBuffer{}
-			m1.WriteAudioTo(recv1)
+			m1.WriteInboundAudioTo(recv1)
 			recv2 := &recvBuffer{}
-			m2.WriteAudioTo(recv2)
+			m2.WriteInboundAudioTo(recv2)
 
 			// Baseline: m1 sends to m2.
 			require.NotNil(t, m1.audioOut.Get())
diff --git a/pkg/sip/media_port_pending_test.go b/pkg/sip/media_port_pending_test.go
index 50c006ea..a8575934 100644
--- a/pkg/sip/media_port_pending_test.go
+++ b/pkg/sip/media_port_pending_test.go
@@ -197,11 +197,11 @@ func TestMediaPort(t *testing.T) {
 
 					var aliceRecvBuf msdk.PCM16Sample
 					aliceHandler := msdk.NewPCM16BufferWriter(&aliceRecvBuf, testRate)
-					alicePort.WriteAudioTo(aliceHandler)
+					alicePort.WriteInboundAudioTo(aliceHandler)
 
 					var bobRecvBuf msdk.PCM16Sample
 					bobHandler := msdk.NewPCM16BufferWriter(&bobRecvBuf, testRate)
-					bobPort.WriteAudioTo(bobHandler)
+					bobPort.WriteInboundAudioTo(bobHandler)
 
 					aliceToBob := alicePort.GetAudioWriter()
 					bobToAlice := bobPort.GetAudioWriter()
diff --git a/pkg/sip/outbound.go b/pkg/sip/outbound.go
index cee0c713..697ebbce 100644
--- a/pkg/sip/outbound.go
+++ b/pkg/sip/outbound.go
@@ -519,7 +519,7 @@ func (c *outboundCall) dialSIP(ctx context.Context, tid traceid.ID) error {
 	if digits := c.sipConf.dtmf; digits != "" {
 		c.setStatus(CallAutomation)
 		// Write initial DTMF to SIP
-		dtmfWriter := c.media.GetDTMFWriter()
+		dtmfWriter := c.media.GetOutboundDTMFWriter()
 		if err := dtmfWriter.WriteSample(&livekit.SipDTMF{
 			Digit: digits,
 		}); err != nil {
@@ -548,13 +548,13 @@ func (c *outboundCall) connectMedia() {
 	if w := c.lkRoom.SwapOutput(c.audioOut); w != nil {
 		_ = w.Close()
 	}
-	c.lkRoom.SetDTMFOutput(c.media.GetDTMFWriter())
+	c.lkRoom.SetDTMFOutput(c.media.GetOutboundDTMFWriter())
 
 	if processor := c.c.handler.GetMediaProcessor(c.sipConf.enabledFeatures, c.sipConf.featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); processor != nil {
 		c.lkRoomIn = processor(c.lkRoomIn)
 	}
-	c.media.WriteAudioTo(c.lkRoomIn)
-	c.media.WriteDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
+	c.media.WriteInboundAudioTo(c.lkRoomIn)
+	c.media.WriteInboundDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
 }
 
 type sipRespFunc func(code sip.StatusCode, hdrs Headers)
@@ -763,7 +763,7 @@ func (c *outboundCall) sipSignal(ctx context.Context, tid traceid.ID) error {
 	}
 
 	c.mon.InviteAccept()
-	if old := c.audioOut.Swap(c.media.GetAudioWriter()); old != nil {
+	if old := c.audioOut.Swap(c.media.GetOutboundAudioWriter()); old != nil {
 		c.log.Warnw("unexpected audio out writer", nil)
 		old.Close()
 	}

From a28910f7265dea8c9f2f03cd9cea7d3e5dde2127 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Thu, 13 Aug 2026 16:32:44 -0700
Subject: [PATCH 3/9] Implement MediaSegment for *Room.

---
 pkg/sip/inbound.go    |  72 +++++++++++++---------
 pkg/sip/media_port.go |   1 -
 pkg/sip/outbound.go   |  41 ++-----------
 pkg/sip/room.go       | 135 ++++++++++++++++++++++++------------------
 4 files changed, 130 insertions(+), 119 deletions(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 0acbfcf8..95394f0d 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -45,7 +45,6 @@ import (
 	lksip "github.com/livekit/protocol/sip"
 	"github.com/livekit/protocol/utils/traceid"
 	"github.com/livekit/psrpc"
-	lksdk "github.com/livekit/server-sdk-go/v2"
 	"github.com/livekit/sipgo/sip"
 
 	"github.com/livekit/sip/pkg/config"
@@ -1113,9 +1112,8 @@ func (c *inboundCall) waitForCallEnd(ctx context.Context, ackReceived <-chan str
 	}
 }
 
-// TODO(alexfish): Update Room so that we don't need this adapater.
 type dtmfEventWriter struct {
-	handler func(msg *livekit.SipDTMF)
+	c *inboundCall
 }
 
 func (w *dtmfEventWriter) String() string {
@@ -1130,11 +1128,31 @@ func (w *dtmfEventWriter) Close() error {
 	return nil
 }
 
-func (w *dtmfEventWriter) WriteSample(sample *livekit.SipDTMF) error {
-	w.handler(sample)
+func (w *dtmfEventWriter) WriteSample(msg *livekit.SipDTMF) error {
+	if msg == nil {
+		return nil
+	}
+
+	if w.c.forwardDTMF.Load() {
+		if err := w.c.lkRoom.GetInboundDTMFWriter().WriteSample(msg); err != nil {
+			w.c.log().Errorw("failed to send dtmf to room", err)
+		}
+	}
+
+	// TODO(alexfish): Just have the channel accept the message instead?
+	event := dtmfEventFromSipDTMF(msg)
+	// We should have enough buffer here.
+	select {
+	case w.c.dtmf <- event:
+	default:
+	}
 	return nil
 }
 
+func (c *inboundCall) getNewInboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
+	return &dtmfEventWriter{c}
+}
+
 func (c *inboundCall) runMediaConn(tid traceid.ID, offerData []byte, mconf *sipMediaConfig, conf *config.Config, featureFlags map[string]string) ([]byte, error) {
 	c.mmu.Lock()
 	defer c.mmu.Unlock()
@@ -1173,13 +1191,11 @@ func (c *inboundCall) runMediaConn(tid traceid.ID, offerData []byte, mconf *sipM
 	c.mon.SDPSize(len(answerData), false)
 	c.log().Debugw("SDP answer", "sdp", string(answerData))
 
-	mp.WriteInboundDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
+	mp.WriteInboundDTMFTo(c.getNewInboundDTMFWriter())
 
 	// Must be set earlier to send the pin prompts.
-	if w := c.lkRoom.SwapOutput(c.audioOut); w != nil {
-		_ = w.Close()
-	}
-	c.lkRoom.SetDTMFOutput(c.media.GetOutboundDTMFWriter())
+	c.lkRoom.WriteOutboundAudioTo(c.audioOut)
+	c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter())
 
 	audio := mp.NegotiatedAudio()
 	if audio == nil {
@@ -1607,16 +1623,16 @@ func (c *inboundCall) createLiveKitParticipant(ctx context.Context, rconf RoomCo
 
 func (c *inboundCall) publishTrack(features []livekit.SIPFeature, featureFlags map[string]string) error {
 	defer c.mon.StageDurTimer("track-publish")()
-	local, err := c.lkRoom.NewParticipantTrack(RoomSampleRate)
+	inboundAudio, err := c.lkRoom.GetInboundAudioWriter()
 	if err != nil {
 		_ = c.lkRoom.Close()
 		return err
 	}
 
 	if audioInProcessor := c.s.handler.GetMediaProcessor(features, featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); audioInProcessor != nil {
-		local = audioInProcessor(local)
+		inboundAudio = audioInProcessor(inboundAudio)
 	}
-	c.media.WriteInboundAudioTo(local)
+	c.media.WriteInboundAudioTo(inboundAudio)
 	return nil
 }
 
@@ -1657,11 +1673,7 @@ func (c *inboundCall) playAudio(ctx context.Context, frames []msdk.PCM16Sample)
 	_ = msdk.PlayAudio[msdk.PCM16Sample](ctx, t, rtp.DefFrameDur, frames)
 }
 
-func (c *inboundCall) handleDTMF(msg *livekit.SipDTMF) {
-	if msg == nil {
-		return
-	}
-
+func dtmfEventFromSipDTMF(msg *livekit.SipDTMF) dtmf.Event {
 	code := byte(msg.Code)
 	digit := byte(0)
 	if len(msg.Digit) == 1 {
@@ -1669,18 +1681,24 @@ func (c *inboundCall) handleDTMF(msg *livekit.SipDTMF) {
 	} else {
 		digit = dtmf.CodeToChar(code)
 	}
-	event := dtmf.Event{
+	return dtmf.Event{
 		Code:  code,
 		Digit: digit,
 	}
+}
+
+func (c *inboundCall) handleDTMF(msg *livekit.SipDTMF) {
+	if msg == nil {
+		return
+	}
 
 	if c.forwardDTMF.Load() {
-		_ = c.lkRoom.SendData(&livekit.SipDTMF{
-			Code:  uint32(code),
-			Digit: string([]byte{digit}),
-		}, lksdk.WithDataPublishReliable(true))
+		c.lkRoom.GetInboundDTMFWriter().WriteSample(msg)
 		return
 	}
+
+	// TODO(alexfish): Just have the channel accept the message instead?
+	event := dtmfEventFromSipDTMF(msg)
 	// We should have enough buffer here.
 	select {
 	case c.dtmf <- event:
@@ -1702,13 +1720,13 @@ func (c *inboundCall) transferCall(ctx context.Context, transferTo string, heade
 		defer rcancel()
 
 		// mute the room audio to the SIP participant
-		w := c.lkRoom.SwapOutput(nil)
+		c.lkRoom.WriteOutboundAudioTo(nil)
 
 		defer func() {
 			if retErr != nil && !c.done.Load() {
-				c.lkRoom.SwapOutput(w)
-			} else if w != nil {
-				w.Close()
+				c.lkRoom.WriteOutboundAudioTo(c.audioOut)
+			} else {
+				c.audioOut.Close()
 			}
 		}()
 
diff --git a/pkg/sip/media_port.go b/pkg/sip/media_port.go
index 7ad4f180..b17effdc 100644
--- a/pkg/sip/media_port.go
+++ b/pkg/sip/media_port.go
@@ -398,7 +398,6 @@ type MediaSegment interface {
 
 	// WriteInboundAudioTo tells the MediaSegment where to write inbound SIP audio.
 	WriteInboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer
-
 	// WriteInboundDTMFTo tells the MediaSegment where to write inbound SIP DTMF.
 	WriteInboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF]
 }
diff --git a/pkg/sip/outbound.go b/pkg/sip/outbound.go
index 697ebbce..37d9221e 100644
--- a/pkg/sip/outbound.go
+++ b/pkg/sip/outbound.go
@@ -31,14 +31,12 @@ import (
 	"golang.org/x/exp/maps"
 
 	msdk "github.com/livekit/media-sdk"
-	"github.com/livekit/media-sdk/dtmf"
 	"github.com/livekit/media-sdk/tones"
 	"github.com/livekit/protocol/livekit"
 	"github.com/livekit/protocol/logger"
 	"github.com/livekit/protocol/utils/guid"
 	"github.com/livekit/protocol/utils/traceid"
 	"github.com/livekit/psrpc"
-	lksdk "github.com/livekit/server-sdk-go/v2"
 	"github.com/livekit/sipgo"
 	"github.com/livekit/sipgo/sip"
 
@@ -385,7 +383,6 @@ func (c *outboundCall) close(ctx context.Context, end EndCall) bool {
 		}
 
 		if r := c.lkRoom; r != nil {
-			_ = r.CloseOutput()
 			_ = r.CloseWithReason(end.Status.DisconnectReason())
 		}
 
@@ -545,16 +542,14 @@ func (c *outboundCall) updateRemoteFromSDP(body []byte) error {
 }
 
 func (c *outboundCall) connectMedia() {
-	if w := c.lkRoom.SwapOutput(c.audioOut); w != nil {
-		_ = w.Close()
-	}
-	c.lkRoom.SetDTMFOutput(c.media.GetOutboundDTMFWriter())
+	c.lkRoom.WriteOutboundAudioTo(c.audioOut)
+	c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter())
 
 	if processor := c.c.handler.GetMediaProcessor(c.sipConf.enabledFeatures, c.sipConf.featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); processor != nil {
 		c.lkRoomIn = processor(c.lkRoomIn)
 	}
 	c.media.WriteInboundAudioTo(c.lkRoomIn)
-	c.media.WriteInboundDTMFTo(&dtmfEventWriter{handler: c.handleDTMF})
+	c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter())
 }
 
 type sipRespFunc func(code sip.StatusCode, hdrs Headers)
@@ -799,30 +794,6 @@ func (c *outboundCall) sipSignal(ctx context.Context, tid traceid.ID) error {
 	return nil
 }
 
-// TODO(alexfish): Update Room so that we don't need this adapter.
-func (c *outboundCall) handleDTMF(msg *livekit.SipDTMF) {
-	if c.lkRoom == nil {
-		return
-	}
-
-	if msg == nil {
-		return
-	}
-
-	code := byte(msg.Code)
-	digit := byte(0)
-	if len(msg.Digit) == 1 {
-		digit = msg.Digit[0]
-	} else {
-		digit = dtmf.CodeToChar(code)
-	}
-
-	_ = c.lkRoom.SendData(&livekit.SipDTMF{
-		Code:  uint32(code),
-		Digit: string([]byte{digit}),
-	}, lksdk.WithDataPublishReliable(true))
-}
-
 func (c *outboundCall) transferCall(ctx context.Context, transferTo string, headers map[string]string, dialtone bool) (retErr error) {
 	ctx, span := Tracer.Start(ctx, "sip.outbound.transferCall")
 	defer span.End()
@@ -839,13 +810,13 @@ func (c *outboundCall) transferCall(ctx context.Context, transferTo string, head
 		defer rcancel()
 
 		// mute the room audio to the SIP participant
-		w := c.lkRoom.SwapOutput(nil)
+		c.lkRoom.WriteOutboundAudioTo(nil)
 
 		defer func() {
 			if retErr != nil && !c.stopped.IsBroken() {
-				c.lkRoom.SwapOutput(w)
+				c.lkRoom.WriteOutboundAudioTo(c.audioOut)
 			} else {
-				w.Close()
+				c.audioOut.Close()
 			}
 		}()
 
diff --git a/pkg/sip/room.go b/pkg/sip/room.go
index 9e362341..82ec9095 100644
--- a/pkg/sip/room.go
+++ b/pkg/sip/room.go
@@ -28,6 +28,7 @@ import (
 	"github.com/pion/webrtc/v4"
 
 	msdk "github.com/livekit/media-sdk"
+	"github.com/livekit/media-sdk/dtmf"
 	"github.com/livekit/media-sdk/g711"
 	"github.com/livekit/media-sdk/jitter"
 	"github.com/livekit/media-sdk/mixer"
@@ -184,17 +185,25 @@ type RoomInterface interface {
 	Subscribed() <-chan struct{}
 	Room() *lksdk.Room
 	Subscribe()
-	Output() msdk.Writer[msdk.PCM16Sample]
-	SwapOutput(out msdk.PCM16Writer) msdk.PCM16Writer
-	CloseOutput() error
-	SetDTMFOutput(w msdk.WriteCloser[*livekit.SipDTMF])
 	Close() error
 	CloseWithReason(reason livekit.DisconnectReason) error
 	Participant() ParticipantInfo
 	NewParticipantTrack(sampleRate int) (msdk.WriteCloser[msdk.PCM16Sample], error)
-	SendData(data lksdk.DataPacket, opts ...lksdk.DataPublishOption) error
 	NewTrack() *mixer.Input
 	lksdk.RoomRPCInterface
+
+	// WriteOutboundAudioTo tells the room where to send audio to.
+	WriteOutboundAudioTo(w msdk.PCM16Writer)
+
+	// WriteOutboundDTMFTo tells the room where to send DTMF to.
+	WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF])
+
+	// GetInboundAudioWriter returns a writer that, when written to, writes
+	// audio to the room.
+	GetInboundAudioWriter() (msdk.PCM16Writer, error)
+	// GetInboundDTMFWriter returns a writer that, when weritten to, writes DTMF
+	// to the room.
+	GetInboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF]
 }
 
 type GetRoomFunc func(log logger.Logger, st *RoomStats) RoomInterface
@@ -207,10 +216,13 @@ type Room struct {
 	log     logger.Logger
 	roomLog logger.Logger // deferred logger
 	// room is cleared on close while SDK callback goroutines still read it.
-	room    atomic.Pointer[lksdk.Room]
-	mix     *mixer.Mixer
-	out     *msdk.SwitchWriter
-	outDtmf atomic.Pointer[msdk.WriteCloser[*livekit.SipDTMF]]
+	room atomic.Pointer[lksdk.Room]
+	mix  *mixer.Mixer
+
+	outboundAudio *msdk.WriteCloserSwitch[msdk.PCM16Sample]
+	outboundDTMF  *msdk.WriteCloserSwitch[*livekit.SipDTMF]
+	inboundDTMF   inboundDTMFWriter
+
 	// p is replaced on every reconnect, since the server issues a new
 	// participant SID, and read concurrently by Participant().
 	p          atomic.Pointer[ParticipantInfo]
@@ -245,10 +257,17 @@ func NewRoom(log logger.Logger, st *RoomStats) *Room {
 	if st == nil {
 		st = &RoomStats{}
 	}
-	r := &Room{log: log, stats: st, out: msdk.NewSwitchWriter(RoomSampleRate)}
+	r := &Room{
+		log:   log,
+		stats: st,
+
+		outboundAudio: msdk.NewWriteCloserSwitch[msdk.PCM16Sample](RoomSampleRate),
+		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](RoomSampleRate),
+	}
+	r.inboundDTMF = inboundDTMFWriter{r}
 
 	var err error
-	r.mix, err = mixer.NewMixer(r.out, rtp.DefFrameDur, 1, mixer.WithStats(&st.Mixer), mixer.WithOutputChannel())
+	r.mix, err = mixer.NewMixer(r.outboundAudio, rtp.DefFrameDur, 1, mixer.WithStats(&st.Mixer), mixer.WithOutputChannel())
 	if err != nil {
 		panic(err)
 	}
@@ -675,50 +694,10 @@ func (r *Room) subscribeAll(room *lksdk.Room) {
 	}
 }
 
-func (r *Room) Output() msdk.Writer[msdk.PCM16Sample] {
-	return r.out.Get()
-}
-
-// SwapOutput sets room audio output and returns the old one.
-// Caller is responsible for closing the old writer.
-func (r *Room) SwapOutput(out msdk.PCM16Writer) msdk.PCM16Writer {
-	if r == nil {
-		return nil
-	}
-	if out == nil {
-		return r.out.Swap(nil)
-	}
-	return r.out.Swap(msdk.ResampleWriter(out, r.mix.SampleRate()))
-}
-
-func (r *Room) CloseOutput() error {
-	w := r.SwapOutput(nil)
-	if w == nil {
-		return nil
-	}
-	return w.Close()
-}
-
-func (r *Room) SetDTMFOutput(w msdk.WriteCloser[*livekit.SipDTMF]) {
-	if r == nil {
-		return
-	}
-	if w == nil {
-		r.outDtmf.Store(nil)
-		return
-	}
-	r.outDtmf.Store(&w)
-}
-
 func (r *Room) sendDTMF(ctx context.Context, msg *livekit.SipDTMF) {
-	outDTMF := r.outDtmf.Load()
-	if outDTMF == nil {
-		r.log.Infow("ignoring dtmf", "digit", msg.Digit)
-		return
-	}
 	// TODO: Separate goroutine?
 	r.log.Debugw("forwarding dtmf to sip", "digit", msg.Digit)
-	(*outDTMF).WriteSample(msg)
+	r.outboundDTMF.WriteSample(msg)
 }
 
 func (r *Room) Close() error {
@@ -729,13 +708,13 @@ func (r *Room) CloseWithReason(reason livekit.DisconnectReason) error {
 	if r == nil {
 		return nil
 	}
-	var err error
+	var errs []error
 	r.closed.Once(func() {
 		defer r.stats.Closed.Store(true)
 
 		r.subscribe.Store(false)
-		err = r.CloseOutput()
-		r.SetDTMFOutput(nil)
+		errs = append(errs, r.outboundAudio.Close())
+		errs = append(errs, r.outboundDTMF.Close())
 		if room := r.room.Swap(nil); room != nil {
 			room.DisconnectWithReason(reason)
 		}
@@ -743,7 +722,7 @@ func (r *Room) CloseWithReason(reason livekit.DisconnectReason) error {
 			r.mix.Stop()
 		}
 	})
-	return err
+	return errors.Join(errs...)
 }
 
 func (r *Room) Participant() ParticipantInfo {
@@ -756,6 +735,7 @@ func (r *Room) Participant() ParticipantInfo {
 	return ParticipantInfo{}
 }
 
+// TODO(alexfish): Remove this from the public interface.
 func (r *Room) NewParticipantTrack(sampleRate int) (msdk.WriteCloser[msdk.PCM16Sample], error) {
 	track, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeOpus}, "audio", "pion")
 	if err != nil {
@@ -797,6 +777,49 @@ func (r *Room) NewTrack() *mixer.Input {
 	return r.mix.NewInput()
 }
 
+func (r *Room) WriteOutboundAudioTo(w msdk.PCM16Writer) {
+	if old := r.outboundAudio.Swap(w); old != nil {
+		old.Close()
+	}
+}
+
+func (r *Room) WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) {
+	if old := r.outboundDTMF.Swap(w); old != nil {
+		old.Close()
+	}
+}
+
+func (r *Room) GetInboundAudioWriter() (msdk.PCM16Writer, error) {
+	return r.NewParticipantTrack(RoomSampleRate)
+}
+
+func (r *Room) GetInboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
+	return &r.inboundDTMF
+}
+
+type inboundDTMFWriter struct {
+	r *Room
+}
+
+func (w *inboundDTMFWriter) String() string {
+	return "inboundDTMFWriter"
+}
+
+func (w *inboundDTMFWriter) SampleRate() int {
+	return dtmf.SampleRate
+}
+
+func (w *inboundDTMFWriter) Close() error {
+	return nil
+}
+
+func (w *inboundDTMFWriter) WriteSample(sample *livekit.SipDTMF) error {
+	if sample == nil {
+		return nil
+	}
+	return w.r.SendData(sample, lksdk.WithDataPublishReliable(true))
+}
+
 // roomOverrideLogger converts errors to warnings and ignore debug
 type roomOverrideLogger struct {
 	logger.Logger

From e9f9a1bad3c91437f4f99323296bc02e04337cd4 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 00:03:10 -0700
Subject: [PATCH 4/9] Fix outbound audio issue when transferring calls.

---
 pkg/sip/inbound.go  |  7 +++----
 pkg/sip/outbound.go |  7 +++----
 pkg/sip/room.go     | 18 ++++++++----------
 3 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 95394f0d..c152eafa 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -1719,14 +1719,13 @@ func (c *inboundCall) transferCall(ctx context.Context, transferTo string, heade
 		rctx, rcancel := context.WithCancel(ctx)
 		defer rcancel()
 
-		// mute the room audio to the SIP participant
-		c.lkRoom.WriteOutboundAudioTo(nil)
+		// Mute the room audio to the SIP participant.
+		// Skip closing the existing writer, which is c.audioOut.
+		_ = c.lkRoom.WriteOutboundAudioTo(nil)
 
 		defer func() {
 			if retErr != nil && !c.done.Load() {
 				c.lkRoom.WriteOutboundAudioTo(c.audioOut)
-			} else {
-				c.audioOut.Close()
 			}
 		}()
 
diff --git a/pkg/sip/outbound.go b/pkg/sip/outbound.go
index 37d9221e..26862fe1 100644
--- a/pkg/sip/outbound.go
+++ b/pkg/sip/outbound.go
@@ -809,14 +809,13 @@ func (c *outboundCall) transferCall(ctx context.Context, transferTo string, head
 		rctx, rcancel := context.WithCancel(ctx)
 		defer rcancel()
 
-		// mute the room audio to the SIP participant
-		c.lkRoom.WriteOutboundAudioTo(nil)
+		// Mute the room audio to the SIP participant.
+		// Skip closing the existing writer, which is c.audioOut.
+		_ = c.lkRoom.WriteOutboundAudioTo(nil)
 
 		defer func() {
 			if retErr != nil && !c.stopped.IsBroken() {
 				c.lkRoom.WriteOutboundAudioTo(c.audioOut)
-			} else {
-				c.audioOut.Close()
 			}
 		}()
 
diff --git a/pkg/sip/room.go b/pkg/sip/room.go
index 82ec9095..f420dca0 100644
--- a/pkg/sip/room.go
+++ b/pkg/sip/room.go
@@ -193,10 +193,12 @@ type RoomInterface interface {
 	lksdk.RoomRPCInterface
 
 	// WriteOutboundAudioTo tells the room where to send audio to.
-	WriteOutboundAudioTo(w msdk.PCM16Writer)
+	// Returns the previously-set writer (if one exists).
+	WriteOutboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer
 
 	// WriteOutboundDTMFTo tells the room where to send DTMF to.
-	WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF])
+	// Returns the previously-set writer (if one exists).
+	WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF]
 
 	// GetInboundAudioWriter returns a writer that, when written to, writes
 	// audio to the room.
@@ -777,16 +779,12 @@ func (r *Room) NewTrack() *mixer.Input {
 	return r.mix.NewInput()
 }
 
-func (r *Room) WriteOutboundAudioTo(w msdk.PCM16Writer) {
-	if old := r.outboundAudio.Swap(w); old != nil {
-		old.Close()
-	}
+func (r *Room) WriteOutboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer {
+	return r.outboundAudio.Swap(w)
 }
 
-func (r *Room) WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) {
-	if old := r.outboundDTMF.Swap(w); old != nil {
-		old.Close()
-	}
+func (r *Room) WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF] {
+	return r.outboundDTMF.Swap(w)
 }
 
 func (r *Room) GetInboundAudioWriter() (msdk.PCM16Writer, error) {

From 25ebe74a7bd4f456c8fba4bee2e2b222ef2c256b Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 10:09:32 -0700
Subject: [PATCH 5/9] Respond to PR feedback.

---
 pkg/sip/inbound.go    | 70 ++++++++++++++++++-------------------------
 pkg/sip/media_port.go | 16 ++++------
 pkg/sip/outbound.go   | 17 ++++++++---
 3 files changed, 48 insertions(+), 55 deletions(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index c152eafa..2c92a5df 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -1014,6 +1014,7 @@ func (c *inboundCall) handleInvite(ctx context.Context, tid traceid.ID, req *sip
 			return err // already sent a response
 		}
 	}
+	c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter())
 	p := &disp.Room.Participant
 	p.Attributes = HeadersToAttrs(p.Attributes, disp.HeadersToAttributes, disp.IncludeHeaders, c.cc, nil)
 	if disp.MaxCallDuration <= 0 || disp.MaxCallDuration > maxCallDuration {
@@ -1112,47 +1113,42 @@ func (c *inboundCall) waitForCallEnd(ctx context.Context, ackReceived <-chan str
 	}
 }
 
-type dtmfEventWriter struct {
-	c *inboundCall
+type pinDTMFWriter struct {
+	dtmfEvents chan<- dtmf.Event
 }
 
-func (w *dtmfEventWriter) String() string {
-	return "dtmfEventWriter"
+func (w *pinDTMFWriter) String() string {
+	return "pinDTMFWriter"
 }
 
-func (w *dtmfEventWriter) SampleRate() int {
+func (w *pinDTMFWriter) SampleRate() int {
 	return dtmf.SampleRate
 }
 
-func (w *dtmfEventWriter) Close() error {
+func (w *pinDTMFWriter) Close() error {
 	return nil
 }
 
-func (w *dtmfEventWriter) WriteSample(msg *livekit.SipDTMF) error {
+func (w *pinDTMFWriter) WriteSample(msg *livekit.SipDTMF) error {
 	if msg == nil {
 		return nil
 	}
 
-	if w.c.forwardDTMF.Load() {
-		if err := w.c.lkRoom.GetInboundDTMFWriter().WriteSample(msg); err != nil {
-			w.c.log().Errorw("failed to send dtmf to room", err)
-		}
-	}
+	// if w.c.forwardDTMF.Load() {
+	// 	if err := w.c.lkRoom.GetInboundDTMFWriter().WriteSample(msg); err != nil {
+	// 		w.c.log().Errorw("failed to send dtmf to room", err)
+	// 	}
+	// }
 
-	// TODO(alexfish): Just have the channel accept the message instead?
 	event := dtmfEventFromSipDTMF(msg)
 	// We should have enough buffer here.
 	select {
-	case w.c.dtmf <- event:
+	case w.dtmfEvents <- event:
 	default:
 	}
 	return nil
 }
 
-func (c *inboundCall) getNewInboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
-	return &dtmfEventWriter{c}
-}
-
 func (c *inboundCall) runMediaConn(tid traceid.ID, offerData []byte, mconf *sipMediaConfig, conf *config.Config, featureFlags map[string]string) ([]byte, error) {
 	c.mmu.Lock()
 	defer c.mmu.Unlock()
@@ -1191,11 +1187,20 @@ func (c *inboundCall) runMediaConn(tid traceid.ID, offerData []byte, mconf *sipM
 	c.mon.SDPSize(len(answerData), false)
 	c.log().Debugw("SDP answer", "sdp", string(answerData))
 
-	mp.WriteInboundDTMFTo(c.getNewInboundDTMFWriter())
+	if old := mp.WriteInboundDTMFTo(&pinDTMFWriter{c.dtmf}); old != nil {
+		c.log().Warnw("media port has unexpected inbound DTMF writer", nil)
+	}
 
 	// Must be set earlier to send the pin prompts.
-	c.lkRoom.WriteOutboundAudioTo(c.audioOut)
-	c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter())
+	if old := c.lkRoom.WriteOutboundAudioTo(c.audioOut); old != nil {
+		c.log().Warnw("room has unexpected outbound audio writer", nil)
+		old.Close()
+	}
+
+	if old := c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter()); old != nil {
+		c.log().Warnw("room has unexpected outbound audio DTMF writer", nil)
+		old.Close()
+	}
 
 	audio := mp.NegotiatedAudio()
 	if audio == nil {
@@ -1632,7 +1637,9 @@ func (c *inboundCall) publishTrack(features []livekit.SIPFeature, featureFlags m
 	if audioInProcessor := c.s.handler.GetMediaProcessor(features, featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); audioInProcessor != nil {
 		inboundAudio = audioInProcessor(inboundAudio)
 	}
-	c.media.WriteInboundAudioTo(inboundAudio)
+	if old := c.media.WriteInboundAudioTo(inboundAudio); old != nil {
+		c.log().Warnw("media port has unexpected inbound audio writer", nil)
+	}
 	return nil
 }
 
@@ -1687,25 +1694,6 @@ func dtmfEventFromSipDTMF(msg *livekit.SipDTMF) dtmf.Event {
 	}
 }
 
-func (c *inboundCall) handleDTMF(msg *livekit.SipDTMF) {
-	if msg == nil {
-		return
-	}
-
-	if c.forwardDTMF.Load() {
-		c.lkRoom.GetInboundDTMFWriter().WriteSample(msg)
-		return
-	}
-
-	// TODO(alexfish): Just have the channel accept the message instead?
-	event := dtmfEventFromSipDTMF(msg)
-	// We should have enough buffer here.
-	select {
-	case c.dtmf <- event:
-	default:
-	}
-}
-
 func (c *inboundCall) transferCall(ctx context.Context, transferTo string, headers map[string]string, dialtone bool) (retErr error) {
 	var err error
 
diff --git a/pkg/sip/media_port.go b/pkg/sip/media_port.go
index b17effdc..4e6f4f91 100644
--- a/pkg/sip/media_port.go
+++ b/pkg/sip/media_port.go
@@ -390,7 +390,12 @@ func (o *MediaOptions) ApplyDefaults() {
 	}
 }
 
-type MediaSegment interface {
+// MediaPort is the insulated media-plane API: UDP/RTP to the wire, SDP negotiation,
+// and audio/DTMF endpoints. It does not know about calls, rooms, or SIP dialogs.
+type MediaPort interface {
+	Close()
+	CloseWait()
+
 	// GetOutboundAudioWriter returns the LK room -> SIP writer.
 	GetOutboundAudioWriter() msdk.PCM16Writer
 	// GetOutboundDTMFWriter returns the LK room -> SIP DTMF writer.
@@ -400,15 +405,6 @@ type MediaSegment interface {
 	WriteInboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer
 	// WriteInboundDTMFTo tells the MediaSegment where to write inbound SIP DTMF.
 	WriteInboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF]
-}
-
-// MediaPort is the insulated media-plane API: UDP/RTP to the wire, SDP negotiation,
-// and audio/DTMF endpoints. It does not know about calls, rooms, or SIP dialogs.
-type MediaPort interface {
-	Close()
-	CloseWait()
-
-	MediaSegment
 
 	// If there is no offer, this generates an offer.
 	// If there is an offer, this simply returns the SDP of that offer.
diff --git a/pkg/sip/outbound.go b/pkg/sip/outbound.go
index 26862fe1..0c730b37 100644
--- a/pkg/sip/outbound.go
+++ b/pkg/sip/outbound.go
@@ -542,14 +542,23 @@ func (c *outboundCall) updateRemoteFromSDP(body []byte) error {
 }
 
 func (c *outboundCall) connectMedia() {
-	c.lkRoom.WriteOutboundAudioTo(c.audioOut)
-	c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter())
+	if old := c.lkRoom.WriteOutboundAudioTo(c.audioOut); old != nil {
+		c.log.Warnw("room has unexpected outbound audio writer", nil)
+	}
+	if old := c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter()); old != nil {
+		c.log.Warnw("room has unexpected outbound DTMF writer", nil)
+	}
 
 	if processor := c.c.handler.GetMediaProcessor(c.sipConf.enabledFeatures, c.sipConf.featureFlags, string(c.cc.ID()), MediaProcessorOpts{InputSampleRate: RoomSampleRate}); processor != nil {
 		c.lkRoomIn = processor(c.lkRoomIn)
 	}
-	c.media.WriteInboundAudioTo(c.lkRoomIn)
-	c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter())
+
+	if old := c.media.WriteInboundAudioTo(c.lkRoomIn); old != nil {
+		c.log.Warnw("media port has unexpected inbound audio writer", nil)
+	}
+	if old := c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter()); old != nil {
+		c.log.Warnw("media port has unexpected inbound DTMF writer", nil)
+	}
 }
 
 type sipRespFunc func(code sip.StatusCode, hdrs Headers)

From f55da47e790ed45670ef3eee681a58543bd7e81c Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 11:12:09 -0700
Subject: [PATCH 6/9] Get tests compiling.

---
 pkg/sip/media_port_negotiation_test.go |  4 +--
 pkg/sip/media_port_test.go             | 16 ++++++------
 pkg/sip/outbound_utilities_test.go     | 34 +++++++++++++-------------
 3 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/pkg/sip/media_port_negotiation_test.go b/pkg/sip/media_port_negotiation_test.go
index 0f0a188b..9c5b877c 100644
--- a/pkg/sip/media_port_negotiation_test.go
+++ b/pkg/sip/media_port_negotiation_test.go
@@ -72,7 +72,7 @@ func roomFrame() msdk.PCM16Sample {
 // writeFrames pushes room audio into the port. Write errors are ignored: the in-memory
 // UDP pipe is bounded, and a peer that is mid-renegotiation may not be draining it.
 func writeFrames(m *mediaPort, frames int) {
-	w := m.GetAudioWriter()
+	w := m.GetOutboundAudioWriter()
 	frame := roomFrame()
 	for range frames {
 		_ = w.WriteSample(frame)
@@ -268,7 +268,7 @@ func TestMediaPortHold(t *testing.T) {
 				assert.True(t, dst.Addr().IsUnspecified(), "held port kept a destination: %v", dst)
 			}
 			assert.Nil(t, m1.audioOut.Get(), "held port still accepts room audio")
-			assert.NoError(t, m1.GetAudioWriter().WriteSample(roomFrame()))
+			assert.NoError(t, m1.GetOutboundAudioWriter().WriteSample(roomFrame()))
 
 			sent := recv2.count()
 			writeFrames(m1, 10)
diff --git a/pkg/sip/media_port_test.go b/pkg/sip/media_port_test.go
index 0317fc80..64866e88 100644
--- a/pkg/sip/media_port_test.go
+++ b/pkg/sip/media_port_test.go
@@ -299,7 +299,7 @@ func newMediaPairWithAddr(t testing.TB, ip1, ip2 netip.Addr, opt1, opt2 *MediaOp
 
 	// TODO(port-refactor): the encode chain gained the always-on 48k resampler, refresh
 	// the expected string once the package builds and this can be run.
-	// w2 := m2.GetAudioWriter()
+	// w2 := m2.GetOutboundAudioWriter()
 	// require.Equal(t, "Switch(16000) -> LatencyEntry -> G722(encode) -> ByteEncoder(16000) -> StatsWriter(G722/8000) -> LatencyExit -> RTPWriteStream(1.1.1.1:10000)", w2.String())
 
 	return m1, m2
@@ -339,7 +339,7 @@ func TestMediaTimeout(t *testing.T) {
 			MediaTimeout:        timeout,
 		}, nil, codec)
 
-		w2 := m2.GetAudioWriter()
+		w2 := m2.GetOutboundAudioWriter()
 		err := w2.WriteSample(msdk.PCM16Sample{0, 0})
 		require.NoError(t, err)
 
@@ -362,7 +362,7 @@ func TestMediaTimeout(t *testing.T) {
 			MediaTimeout:        timeout,
 		}, nil, codec)
 
-		w2 := m2.GetAudioWriter()
+		w2 := m2.GetOutboundAudioWriter()
 
 		for i := 0; i < 10; i++ {
 			err := w2.WriteSample(msdk.PCM16Sample{0, 0})
@@ -382,7 +382,7 @@ func TestMediaTimeout(t *testing.T) {
 			MediaTimeout:        timeout,
 		}, nil, codec)
 
-		w2 := m2.GetAudioWriter()
+		w2 := m2.GetOutboundAudioWriter()
 
 		for i := 0; i < 5; i++ {
 			err := w2.WriteSample(msdk.PCM16Sample{0, 0})
@@ -440,7 +440,7 @@ func TestMediaTimeout(t *testing.T) {
 			MediaTimeout:        timeout,
 		}, nil, codec)
 
-		w2 := m2.GetAudioWriter()
+		w2 := m2.GetOutboundAudioWriter()
 
 		for i := 0; i < 5; i++ {
 			err := w2.WriteSample(msdk.PCM16Sample{0, 0})
@@ -480,7 +480,7 @@ func TestSymmetricRTP(t *testing.T) {
 		newAddr := netip.AddrPortFrom(newIP("9.9.9.9"), 9999)
 		c2.addr = newAddr
 
-		err := m2.GetAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
+		err := m2.GetOutboundAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
 		require.NoError(t, err)
 
 		select {
@@ -504,7 +504,7 @@ func TestSymmetricRTP(t *testing.T) {
 		newAddr := netip.AddrPortFrom(newIP("9.9.9.9"), 9999)
 		c2.addr = newAddr
 
-		err := m2.GetAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
+		err := m2.GetOutboundAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
 		require.NoError(t, err)
 
 		select {
@@ -534,7 +534,7 @@ func TestSymmetricRTP(t *testing.T) {
 		newAddr := netip.AddrPortFrom(newIP("3.3.3.3"), 9999)
 		c2.addr = newAddr
 
-		err := m2.GetAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
+		err := m2.GetOutboundAudioWriter().WriteSample(msdk.PCM16Sample{0, 0})
 		require.NoError(t, err)
 
 		select {
diff --git a/pkg/sip/outbound_utilities_test.go b/pkg/sip/outbound_utilities_test.go
index 9e850fe5..1b4136de 100644
--- a/pkg/sip/outbound_utilities_test.go
+++ b/pkg/sip/outbound_utilities_test.go
@@ -102,6 +102,8 @@ type testRoom struct {
 	room *Room
 }
 
+var _ RoomInterface = (*testRoom)(nil)
+
 type testRoomConfig struct {
 	ringForever bool
 }
@@ -122,15 +124,17 @@ func newTestRoomWithConfig(log logger.Logger, st *RoomStats, cfg *testRoomConfig
 	}
 	// Create a Room with all the necessary structure but skip connection
 	room := &Room{
-		log:       log,
-		stats:     st,
-		out:       msdk.NewSwitchWriter(RoomSampleRate),
-		subscribe: atomic.Bool{},
+		log:           log,
+		stats:         st,
+		outboundAudio: msdk.NewWriteCloserSwitch[msdk.PCM16Sample](RoomSampleRate),
+		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](RoomSampleRate),
+		subscribe:     atomic.Bool{},
 	}
+	room.inboundDTMF = inboundDTMFWriter{room}
 
 	// Create mixer
 	var err error
-	room.mix, err = mixer.NewMixer(room.out, rtp.DefFrameDur, 1, mixer.WithStats(&st.Mixer), mixer.WithOutputChannel())
+	room.mix, err = mixer.NewMixer(room.outboundAudio, rtp.DefFrameDur, 1, mixer.WithStats(&st.Mixer), mixer.WithOutputChannel())
 	if err != nil {
 		panic(err)
 	}
@@ -202,20 +206,20 @@ func (r *testRoom) Subscribe() {
 	r.room.Subscribe()
 }
 
-func (r *testRoom) Output() msdk.Writer[msdk.PCM16Sample] {
-	return r.room.Output()
+func (r *testRoom) WriteOutboundAudioTo(w msdk.PCM16Writer) msdk.PCM16Writer {
+	return r.room.WriteOutboundAudioTo(w)
 }
 
-func (r *testRoom) SwapOutput(out msdk.PCM16Writer) msdk.PCM16Writer {
-	return r.room.SwapOutput(out)
+func (r *testRoom) WriteOutboundDTMFTo(w msdk.WriteCloser[*livekit.SipDTMF]) msdk.WriteCloser[*livekit.SipDTMF] {
+	return r.room.WriteOutboundDTMFTo(w)
 }
 
-func (r *testRoom) CloseOutput() error {
-	return r.room.CloseOutput()
+func (r *testRoom) GetInboundAudioWriter() (msdk.PCM16Writer, error) {
+	return r.NewParticipantTrack(RoomSampleRate)
 }
 
-func (r *testRoom) SetDTMFOutput(w msdk.WriteCloser[*livekit.SipDTMF]) {
-	r.room.SetDTMFOutput(w)
+func (r *testRoom) GetInboundDTMFWriter() msdk.WriteCloser[*livekit.SipDTMF] {
+	return r.room.GetInboundDTMFWriter()
 }
 
 func (r *testRoom) Close() error {
@@ -256,10 +260,6 @@ func (w *noOpWriter) Close() error {
 	return nil
 }
 
-func (r *testRoom) SendData(data lksdk.DataPacket, opts ...lksdk.DataPublishOption) error {
-	return r.room.SendData(data, opts...)
-}
-
 func (r *testRoom) NewTrack() *mixer.Input {
 	return r.room.NewTrack()
 }

From e87497315e95a5310ba4dbb777c4044bc58e00a9 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 11:21:15 -0700
Subject: [PATCH 7/9] Add back in DTMF forwarding check.

---
 pkg/sip/inbound.go  | 9 +--------
 pkg/sip/outbound.go | 6 ++++++
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 2c92a5df..3a29ebd0 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -717,7 +717,6 @@ type inboundCall struct {
 	lkRoom      RoomInterface   // LiveKit room; only active after correct pin is entered
 	callDur     func() time.Duration
 	joinDur     func() time.Duration
-	forwardDTMF atomic.Bool
 	done        atomic.Bool
 	started     core.Fuse
 	stats       Stats
@@ -1014,6 +1013,7 @@ func (c *inboundCall) handleInvite(ctx context.Context, tid traceid.ID, req *sip
 			return err // already sent a response
 		}
 	}
+
 	c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter())
 	p := &disp.Room.Participant
 	p.Attributes = HeadersToAttrs(p.Attributes, disp.HeadersToAttributes, disp.IncludeHeaders, c.cc, nil)
@@ -1134,12 +1134,6 @@ func (w *pinDTMFWriter) WriteSample(msg *livekit.SipDTMF) error {
 		return nil
 	}
 
-	// if w.c.forwardDTMF.Load() {
-	// 	if err := w.c.lkRoom.GetInboundDTMFWriter().WriteSample(msg); err != nil {
-	// 		w.c.log().Errorw("failed to send dtmf to room", err)
-	// 	}
-	// }
-
 	event := dtmfEventFromSipDTMF(msg)
 	// We should have enough buffer here.
 	select {
@@ -1597,7 +1591,6 @@ func (c *inboundCall) createLiveKitParticipant(ctx context.Context, rconf RoomCo
 		partConf.Attributes[k] = v
 	}
 	partConf.Attributes[livekit.AttrSIPCallStatus] = status.Attribute()
-	c.forwardDTMF.Store(true)
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
diff --git a/pkg/sip/outbound.go b/pkg/sip/outbound.go
index 0c730b37..2cf4f36a 100644
--- a/pkg/sip/outbound.go
+++ b/pkg/sip/outbound.go
@@ -543,9 +543,12 @@ func (c *outboundCall) updateRemoteFromSDP(body []byte) error {
 
 func (c *outboundCall) connectMedia() {
 	if old := c.lkRoom.WriteOutboundAudioTo(c.audioOut); old != nil {
+		old.Close()
 		c.log.Warnw("room has unexpected outbound audio writer", nil)
 	}
+
 	if old := c.lkRoom.WriteOutboundDTMFTo(c.media.GetOutboundDTMFWriter()); old != nil {
+		old.Close()
 		c.log.Warnw("room has unexpected outbound DTMF writer", nil)
 	}
 
@@ -554,9 +557,12 @@ func (c *outboundCall) connectMedia() {
 	}
 
 	if old := c.media.WriteInboundAudioTo(c.lkRoomIn); old != nil {
+		old.Close()
 		c.log.Warnw("media port has unexpected inbound audio writer", nil)
 	}
+
 	if old := c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter()); old != nil {
+		old.Close()
 		c.log.Warnw("media port has unexpected inbound DTMF writer", nil)
 	}
 }

From 4c0d7813f2b0f3340b51c4236edb36cf02402a52 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 11:54:11 -0700
Subject: [PATCH 8/9] Move DTMF wiring.

---
 pkg/sip/inbound.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/pkg/sip/inbound.go b/pkg/sip/inbound.go
index 3a29ebd0..7dcb94d3 100644
--- a/pkg/sip/inbound.go
+++ b/pkg/sip/inbound.go
@@ -1014,7 +1014,6 @@ func (c *inboundCall) handleInvite(ctx context.Context, tid traceid.ID, req *sip
 		}
 	}
 
-	c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter())
 	p := &disp.Room.Participant
 	p.Attributes = HeadersToAttrs(p.Attributes, disp.HeadersToAttributes, disp.IncludeHeaders, c.cc, nil)
 	if disp.MaxCallDuration <= 0 || disp.MaxCallDuration > maxCallDuration {
@@ -1632,6 +1631,11 @@ func (c *inboundCall) publishTrack(features []livekit.SIPFeature, featureFlags m
 	}
 	if old := c.media.WriteInboundAudioTo(inboundAudio); old != nil {
 		c.log().Warnw("media port has unexpected inbound audio writer", nil)
+		old.Close()
+	}
+	if old := c.media.WriteInboundDTMFTo(c.lkRoom.GetInboundDTMFWriter()); old != nil {
+		c.log().Warnw("media port has unexpected inbound dtmf writer", nil)
+		old.Close()
 	}
 	return nil
 }

From ad3eef42b74f3de8aea4799143f3183e444e2e78 Mon Sep 17 00:00:00 2001
From: alexfish8 <alex.fish@livekit.io>
Date: Fri, 14 Aug 2026 11:55:46 -0700
Subject: [PATCH 9/9] Fix test.

---
 pkg/sip/outbound_utilities_test.go | 2 +-
 pkg/sip/room.go                    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkg/sip/outbound_utilities_test.go b/pkg/sip/outbound_utilities_test.go
index 1b4136de..53262b77 100644
--- a/pkg/sip/outbound_utilities_test.go
+++ b/pkg/sip/outbound_utilities_test.go
@@ -127,7 +127,7 @@ func newTestRoomWithConfig(log logger.Logger, st *RoomStats, cfg *testRoomConfig
 		log:           log,
 		stats:         st,
 		outboundAudio: msdk.NewWriteCloserSwitch[msdk.PCM16Sample](RoomSampleRate),
-		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](RoomSampleRate),
+		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](0),
 		subscribe:     atomic.Bool{},
 	}
 	room.inboundDTMF = inboundDTMFWriter{room}
diff --git a/pkg/sip/room.go b/pkg/sip/room.go
index f420dca0..6b98c7b9 100644
--- a/pkg/sip/room.go
+++ b/pkg/sip/room.go
@@ -264,7 +264,7 @@ func NewRoom(log logger.Logger, st *RoomStats) *Room {
 		stats: st,
 
 		outboundAudio: msdk.NewWriteCloserSwitch[msdk.PCM16Sample](RoomSampleRate),
-		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](RoomSampleRate),
+		outboundDTMF:  msdk.NewWriteCloserSwitch[*livekit.SipDTMF](0),
 	}
 	r.inboundDTMF = inboundDTMFWriter{r}