Update wyoming readme about events

internal/exec/README.md

@@ -0,0 +1,12 @@
+## Backchannel
+
+- You can check audio card names in the **Go2rtc > WebUI > Add**
+- You can specify multiple backchannel lines with different codecs
+
+```yaml
+sources:
+  two_way_audio_win:
+    - exec:ffmpeg -hide_banner -f dshow -i "audio=Microphone (High Definition Audio Device)" -c pcm_s16le -ar 16000 -ac 1 -f wav -
+    - exec:ffplay -nodisp -probesize 32 -f s16le -ar 16000 -#backchannel=1#audio=s16le/16000
+    - exec:ffplay -nodisp -probesize 32 -f alaw -ar 8000 -#backchannel=1#audio=alaw/8000
+```

internal/exec/exec.go

@@ -19,9 +19,9 @@ import (
 	"github.com/AlexxIT/go2rtc/internal/streams"
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/magic"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
 	pkg "github.com/AlexxIT/go2rtc/pkg/rtsp"
 	"github.com/AlexxIT/go2rtc/pkg/shell"
-	"github.com/AlexxIT/go2rtc/pkg/stdin"
 	"github.com/rs/zerolog"
 )
 
@@ -86,7 +86,7 @@ func execHandle(rawURL string) (prod core.Producer, err error) {
 	}
 
 	if query.Get("backchannel") == "1" {
-		return stdin.NewClient(cmd)
+		return pcm.NewBackchannel(cmd, query.Get("audio"))
 	}
 
 	if path == "" {

internal/expr/expr.go

@@ -12,7 +12,7 @@ func Init() {
 	log := app.GetLogger("expr")
 
 	streams.RedirectFunc("expr", func(url string) (string, error) {
-		v, err := expr.Run(url[5:])
+		v, err := expr.Eval(url[5:], nil)
 		if err != nil {
 			return "", err
 		}

internal/streams/play.go

@@ -7,7 +7,7 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/core"
 )
 
-func (s *Stream) Play(source string) error {
+func (s *Stream) Play(urlOrProd any) error {
 	s.mu.Lock()
 	for _, producer := range s.producers {
 		if producer.state == stateInternal && producer.conn != nil {
@@ -16,12 +16,18 @@ func (s *Stream) Play(source string) error {
 	}
 	s.mu.Unlock()
 
-	if source == "" {
-		return nil
-	}
-
+	var source string
 	var src core.Producer
 
+	switch urlOrProd.(type) {
+	case string:
+		if source = urlOrProd.(string); source == "" {
+			return nil
+		}
+	case core.Producer:
+		src = urlOrProd.(core.Producer)
+	}
+
 	for _, producer := range s.producers {
 		if producer.conn == nil {
 			continue

internal/wyoming/README.md

@@ -0,0 +1,267 @@
+# Wyoming
+
+This module provide [Wyoming Protocol](https://www.home-assistant.io/integrations/wyoming/) support to create local voice assistants using [Home Assistant](https://www.home-assistant.io/).
+
+- go2rtc can act as [Wyoming Satellite](https://github.com/rhasspy/wyoming-satellite)
+- go2rtc can act as [Wyoming External Microphone](https://github.com/rhasspy/wyoming-mic-external)
+- go2rtc can act as [Wyoming External Sound](https://github.com/rhasspy/wyoming-snd-external)
+- any supported audio source with PCM codec can be used as audio input
+- any supported two-way audio source with PCM codec can be used as audio output
+- any desktop/server microphone/speaker can be used as two-way audio source
+  - supported any OS via FFmpeg or any similar software
+  - supported Linux via alsa source
+- you can change the behavior using the built-in scripting engine
+
+## Typical Voice Pipeline
+
+1. Audio stream (MIC)
+   - any audio source with PCM codec support (include PCMA/PCMU)
+2. Voice Activity Detector (VAD)
+3. Wake Word (WAKE)
+   - [OpenWakeWord](https://www.home-assistant.io/voice_control/create_wake_word/)
+4. Speech-to-Text (STT)
+   - [Whisper](https://github.com/home-assistant/addons/blob/master/whisper/README.md) 
+   - [Vosk](https://github.com/rhasspy/hassio-addons/blob/master/vosk/README.md)
+5. Conversation agent (INTENT)
+   - [Home Assistant](https://www.home-assistant.io/integrations/conversation/)
+6. Text-to-speech (TTS)
+   - [Google Translate](https://www.home-assistant.io/integrations/google_translate/)
+   - [Piper](https://github.com/home-assistant/addons/blob/master/piper/README.md)
+7. Audio stream (SND)
+   - any source with two-way audio (backchannel) and PCM codec support (include PCMA/PCMU)
+
+You can use a large number of different projects for WAKE, STT, INTENT and TTS thanks to the Home Assistant.
+
+And you can use a large number of different technologies for MIC and SND thanks to Go2rtc.
+
+## Configuration
+
+You can optionally specify WAKE service. So go2rtc will start transmitting audio to Home Assistant only after WAKE word. If the WAKE service cannot be connected to or not specified - go2rtc will pass all audio to Home Assistant. In this case WAKE service must be configured in your Voice Assistant pipeline.
+
+You can optionally specify VAD threshold. So go2rtc will start transmitting audio to WAKE service only after some audio noise.
+
+Your stream must support audio transmission in PCM codec (include PCMA/PCMU).
+
+```yaml
+wyoming:
+  stream_name_from_streams_section:
+    listen: :10700 
+    name: "My Satellite"                # optional name
+    wake_uri: tcp://192.168.1.23:10400  # optional WAKE service
+    vad_threshold: 1                    # optional VAD threshold (from 0.1 to 3.5)
+```
+
+Home Assistant -> Settings -> Integrations -> Add -> Wyoming Protocol -> Host + Port from `go2rtc.yaml`
+
+Select one or multiple wake words:
+```yaml
+wake_uri: tcp://192.168.1.23:10400?name=alexa_v0.1&name=hey_jarvis_v0.1&name=hey_mycroft_v0.1&name=hey_rhasspy_v0.1&name=ok_nabu_v0.1
+```
+
+## Events
+
+You can add wyoming event handling using the [expr](https://github.com/AlexxIT/go2rtc/blob/master/internal/expr/README.md) language. For example, to pronounce TTS on some media player from HA.
+
+Turn on the logs to see what kind of events happens.
+
+This is what the default scripts look like:
+
+```yaml
+wyoming:
+  script_example:
+    event:
+      run-satellite: Detect()
+      pause-satellite: Stop()
+      voice-stopped: Pause()
+      audio-stop: PlayAudio() && WriteEvent("played") && Detect()
+      error: Detect()
+      internal-run: WriteEvent("run-pipeline", '{"start_stage":"wake","end_stage":"tts"}') && Stream()
+      internal-detection: WriteEvent("run-pipeline", '{"start_stage":"asr","end_stage":"tts"}') && Stream()
+```
+
+If you write a script for an event - the default action is no longer executed. You need to repeat the necessary steps yourself.
+
+In addition to the standard events, there are two additional events:
+
+- `internal-run` - called after `Detect()` when VAD detected, but WAKE service unavailable
+- `internal-detection` - called after `Detect()` when WAKE word detected
+
+**Example 1.** You want to play a sound file when a wake word detected (only `wav` supported):
+
+- `PlayFile` and `PlayAudio` functions are executed synchronously, the following steps will be executed only after they are completed
+
+```yaml
+wyoming:
+  script_example:
+    event:
+      internal-detection: PlayFile('/media/beep.wav') && WriteEvent("run-pipeline", '{"start_stage":"asr","end_stage":"tts"}') && Stream()
+```
+
+**Example 2.** You want to play TTS on a Home Assistant media player:
+
+Each event has a `Type` and `Data` in JSON format. You can use their values in scripts.
+
+- in the `synthesize` step, we get the value of the `text` and call the HA REST API
+- in the `audio-stop` step we get the duration of the TTS in seconds, wait for this time and start the pipeline again
+
+```yaml
+wyoming:
+  script_example:
+    event:
+      synthesize: |
+        let text = fromJSON(Data).text;
+        let token = 'eyJhbGci...';
+        fetch('http://localhost:8123/api/services/tts/speak', {
+          method: 'POST',
+          headers: {'Authorization': 'Bearer '+token,'Content-Type': 'application/json'},
+          body: toJSON({
+            entity_id: 'tts.google_translate_com',
+            media_player_entity_id: 'media_player.google_nest',
+            message: text,
+            language: 'en',
+          }),
+        }).ok
+      audio-stop: |
+        let timestamp = fromJSON(Data).timestamp;
+        let delay = string(timestamp)+'s';
+        Sleep(delay) && WriteEvent("played") && Detect()
+```
+
+## Config examples
+
+Satellite on Windows server using FFmpeg and FFplay.
+
+```yaml
+streams:
+  satellite_win:
+    - exec:ffmpeg -hide_banner -f dshow -i "audio=Microphone (High Definition Audio Device)" -c pcm_s16le -ar 16000 -ac 1 -f wav -
+    - exec:ffplay -hide_banner -nodisp -probesize 32 -f s16le -ar 22050 -#backchannel=1#audio=s16le/22050
+
+wyoming:
+  satellite_win:
+    listen: :10700
+    name: "Windows Satellite"
+    wake_uri: tcp://192.168.1.23:10400
+    vad_threshold: 1
+```
+
+Satellite on Dahua camera with two-way audio support.
+
+```yaml
+streams:
+  dahua_camera:
+    - rtsp://admin:password@192.168.1.123/cam/realmonitor?channel=1&subtype=1&unicast=true&proto=Onvif
+
+wyoming:
+  dahua_camera:
+    listen: :10700
+    name: "Dahua Satellite"
+    wake_uri: tcp://192.168.1.23:10400
+    vad_threshold: 1
+```
+
+Satellite on Dahua camera with two-way audio support.
+
+```yaml
+streams:
+  wyoming_external:
+     - wyoming://192.168.1.23:10600                # wyoming-mic-external
+     - wyoming://192.168.1.23:10601?backchannel=1  # wyoming-snd-external
+
+wyoming:
+   wyoming_external:
+    listen: :10700
+    name: "Wyoming Satellite"
+    wake_uri: tcp://192.168.1.23:10400
+    vad_threshold: 1
+```
+
+## Wyoming External Microphone and Sound
+
+Advanced users, who want to enjoy the [Wyoming Satellite](https://github.com/rhasspy/wyoming-satellite) project, can use go2rtc as a [Wyoming External Microphone](https://github.com/rhasspy/wyoming-mic-external) or [Wyoming External Sound](https://github.com/rhasspy/wyoming-snd-external).
+
+**go2rtc.yaml**
+
+```yaml
+streams:
+  wyoming_mic_external:
+    - exec:ffmpeg -hide_banner -f dshow -i "audio=Microphone (High Definition Audio Device)" -c pcm_s16le -ar 16000 -ac 1 -f wav -
+  wyoming_snd_external:
+    - exec:ffplay -hide_banner -nodisp -probesize 32 -f s16le -ar 22050 -#backchannel=1#audio=s16le/22050
+
+wyoming:
+  wyoming_mic_external:
+    listen: :10600
+    mode: mic
+  wyoming_snd_external:
+    listen: :10601
+    mode: snd
+```
+
+**docker-compose.yml**
+
+```yaml
+version: "3.8"
+services:
+  satellite:
+    build: wyoming-satellite  # https://github.com/rhasspy/wyoming-satellite
+    ports:
+      - "10700:10700"
+    command:
+      - "--name"
+      - "my satellite"
+      - "--mic-uri"
+      - "tcp://192.168.1.23:10600"
+      - "--snd-uri"
+      - "tcp://192.168.1.23:10601"
+      - "--debug"
+```
+
+## Wyoming External Source
+
+**go2rtc.yaml**
+
+```yaml
+streams:
+  wyoming_external:
+    - wyoming://192.168.1.23:10600
+    - wyoming://192.168.1.23:10601?backchannel=1
+```
+
+**docker-compose.yml**
+
+```yaml
+version: "3.8"
+services:
+   microphone:
+      build: wyoming-mic-external  # https://github.com/rhasspy/wyoming-mic-external
+      ports:
+         - "10600:10600"
+      devices:
+         - /dev/snd:/dev/snd
+      group_add:
+         - audio
+      command:
+         - "--device"
+         - "sysdefault"
+         - "--debug"
+   playback:
+      build: wyoming-snd-external  # https://github.com/rhasspy/wyoming-snd-external
+      ports:
+         - "10601:10601"
+      devices:
+         - /dev/snd:/dev/snd
+      group_add:
+         - audio
+      command:
+         - "--device"
+         - "sysdefault"
+         - "--debug"
+```
+
+## Debug
+
+```yaml
+log:
+  wyoming: trace
+```

internal/wyoming/wyoming.go

@@ -0,0 +1,106 @@
+package wyoming
+
+import (
+	"net"
+
+	"github.com/AlexxIT/go2rtc/internal/app"
+	"github.com/AlexxIT/go2rtc/internal/streams"
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/wyoming"
+	"github.com/rs/zerolog"
+)
+
+func Init() {
+	streams.HandleFunc("wyoming", wyoming.Dial)
+
+	// server
+	var cfg struct {
+		Mod map[string]struct {
+			Listen       string            `yaml:"listen"`
+			Name         string            `yaml:"name"`
+			Mode         string            `yaml:"mode"`
+			Event        map[string]string `yaml:"event"`
+			WakeURI      string            `yaml:"wake_uri"`
+			VADThreshold float32           `yaml:"vad_threshold"`
+		} `yaml:"wyoming"`
+	}
+	app.LoadConfig(&cfg)
+
+	log = app.GetLogger("wyoming")
+
+	for name, cfg := range cfg.Mod {
+		stream := streams.Get(name)
+		if stream == nil {
+			log.Warn().Msgf("[wyoming] missing stream: %s", name)
+			continue
+		}
+
+		if cfg.Name == "" {
+			cfg.Name = name
+		}
+
+		srv := &wyoming.Server{
+			Name:         cfg.Name,
+			Event:        cfg.Event,
+			VADThreshold: int16(1000 * cfg.VADThreshold), // 1.0 => 1000
+			WakeURI:      cfg.WakeURI,
+			MicHandler: func(cons core.Consumer) error {
+				if err := stream.AddConsumer(cons); err != nil {
+					return err
+				}
+				// not best solution
+				if i, ok := cons.(interface{ OnClose(func()) }); ok {
+					i.OnClose(func() {
+						stream.RemoveConsumer(cons)
+					})
+				}
+				return nil
+			},
+			SndHandler: func(prod core.Producer) error {
+				return stream.Play(prod)
+			},
+			Trace: func(format string, v ...any) {
+				log.Trace().Msgf("[wyoming] "+format, v...)
+			},
+			Error: func(format string, v ...any) {
+				log.Error().Msgf("[wyoming] "+format, v...)
+			},
+		}
+		go serve(srv, cfg.Mode, cfg.Listen)
+	}
+}
+
+var log zerolog.Logger
+
+func serve(srv *wyoming.Server, mode, address string) {
+	ln, err := net.Listen("tcp", address)
+	if err != nil {
+		log.Warn().Err(err).Msgf("[wyoming] listen")
+	}
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			return
+		}
+
+		go handle(srv, mode, conn)
+	}
+}
+
+func handle(srv *wyoming.Server, mode string, conn net.Conn) {
+	addr := conn.RemoteAddr()
+
+	log.Trace().Msgf("[wyoming] %s connected", addr)
+
+	switch mode {
+	case "mic":
+		srv.HandleMic(conn)
+	case "snd":
+		srv.HandleSnd(conn)
+	default:
+		srv.Handle(conn)
+	}
+
+	log.Trace().Msgf("[wyoming] %s disconnected", addr)
+}

main.go

@@ -38,6 +38,7 @@ import (
 	"github.com/AlexxIT/go2rtc/internal/v4l2"
 	"github.com/AlexxIT/go2rtc/internal/webrtc"
 	"github.com/AlexxIT/go2rtc/internal/webtorrent"
+	"github.com/AlexxIT/go2rtc/internal/wyoming"
 	"github.com/AlexxIT/go2rtc/pkg/shell"
 )
 
@@ -69,6 +70,7 @@ func main() {
 	hass.Init()       // hass source, Hass API server
 	onvif.Init()      // onvif source, ONVIF API server
 	webtorrent.Init() // webtorrent source, WebTorrent module
+	wyoming.Init()
 
 	// 5. Other sources
 

pkg/core/codec.go

@@ -249,3 +249,36 @@ func DecodeH264(fmtp string) (profile string, level byte) {
 	}
 	return
 }
+
+func ParseCodecString(s string) *Codec {
+	var codec Codec
+
+	ss := strings.Split(s, "/")
+	switch strings.ToLower(ss[0]) {
+	case "pcm_s16be", "s16be", "pcm":
+		codec.Name = CodecPCM
+	case "pcm_s16le", "s16le", "pcml":
+		codec.Name = CodecPCML
+	case "pcm_alaw", "alaw", "pcma":
+		codec.Name = CodecPCMA
+	case "pcm_mulaw", "mulaw", "pcmu":
+		codec.Name = CodecPCMU
+	case "aac", "mpeg4-generic":
+		codec.Name = CodecAAC
+	case "opus":
+		codec.Name = CodecOpus
+	case "flac":
+		codec.Name = CodecFLAC
+	default:
+		return nil
+	}
+
+	if len(ss) >= 2 {
+		codec.ClockRate = uint32(Atoi(ss[1]))
+	}
+	if len(ss) >= 3 {
+		codec.Channels = uint8(Atoi(ss[1]))
+	}
+
+	return &codec
+}

pkg/expr/expr.go

@@ -6,17 +6,24 @@ import (
 	"io"
 	"net/http"
 	"regexp"
+	"strings"
 
 	"github.com/AlexxIT/go2rtc/pkg/tcp"
 	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/vm"
 )
 
-func newRequest(method, url string, headers map[string]any) (*http.Request, error) {
+func newRequest(method, url string, headers map[string]any, body string) (*http.Request, error) {
+	var rd io.Reader
+
 	if method == "" {
 		method = "GET"
 	}
+	if body != "" {
+		rd = strings.NewReader(body)
+	}
 
-	req, err := http.NewRequest(method, url, nil)
+	req, err := http.NewRequest(method, url, rd)
 	if err != nil {
 		return nil, err
 	}
@@ -55,7 +62,8 @@ var Options = []expr.Option{
 				options := params[1].(map[string]any)
 				method, _ := options["method"].(string)
 				headers, _ := options["headers"].(map[string]any)
-				req, err = newRequest(method, url, headers)
+				body, _ := options["body"].(string)
+				req, err = newRequest(method, url, headers, body)
 			} else {
 				req, err = http.NewRequest("GET", url, nil)
 			}
@@ -105,11 +113,19 @@ var Options = []expr.Option{
 	),
 }
 
-func Run(input string) (any, error) {
-	program, err := expr.Compile(input, Options...)
+func Compile(input string) (*vm.Program, error) {
+	return expr.Compile(input, Options...)
+}
+
+func Eval(input string, env any) (any, error) {
+	program, err := Compile(input)
 	if err != nil {
 		return nil, err
 	}
 
-	return expr.Run(program, nil)
+	return expr.Run(program, env)
+}
+
+func Run(program *vm.Program, env any) (any, error) {
+	return vm.Run(program, env)
 }

pkg/expr/expr_test.go

@@ -7,11 +7,11 @@ import (
 )
 
 func TestMatchHost(t *testing.T) {
-	v, err := Run(`
+	v, err := Eval(`
 let url = "rtsp://user:pass@192.168.1.123/cam/realmonitor?...";
 let host = match(url, "//[^/]+")[0][2:];
 host
-`)
+`, nil)
 	require.Nil(t, err)
 	require.Equal(t, "user:pass@192.168.1.123", v)
 }

pkg/pcm/backchannel.go

@@ -0,0 +1,69 @@
+package pcm
+
+import (
+	"errors"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/shell"
+	"github.com/pion/rtp"
+)
+
+type Backchannel struct {
+	core.Connection
+	cmd *shell.Command
+}
+
+func NewBackchannel(cmd *shell.Command, audio string) (core.Producer, error) {
+	var codec *core.Codec
+
+	if audio == "" {
+		// default codec
+		codec = &core.Codec{Name: core.CodecPCML, ClockRate: 16000}
+	} else if codec = core.ParseCodecString(audio); codec == nil {
+		return nil, errors.New("pcm: unsupported audio format: " + audio)
+	}
+
+	medias := []*core.Media{
+		{
+			Kind:      core.KindAudio,
+			Direction: core.DirectionSendonly,
+			Codecs:    []*core.Codec{codec},
+		},
+	}
+
+	return &Backchannel{
+		Connection: core.Connection{
+			ID:         core.NewID(),
+			FormatName: "pcm",
+			Protocol:   "pipe",
+			Medias:     medias,
+			Transport:  cmd,
+		},
+		cmd: cmd,
+	}, nil
+}
+
+func (c *Backchannel) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
+	return nil, core.ErrCantGetTrack
+}
+
+func (c *Backchannel) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
+	wr, err := c.cmd.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	sender := core.NewSender(media, track.Codec)
+	sender.Handler = func(packet *rtp.Packet) {
+		if n, err := wr.Write(packet.Payload); err != nil {
+			c.Send += n
+		}
+	}
+	sender.HandleRTP(track)
+	c.Senders = append(c.Senders, sender)
+	return nil
+}
+
+func (c *Backchannel) Start() error {
+	return c.cmd.Run()
+}

pkg/pcm/handlers.go

@@ -2,6 +2,7 @@ package pcm
 
 import (
 	"sync"
+	"time"
 
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/pion/rtp"
@@ -82,18 +83,27 @@ func TranscodeHandler(dst, src *core.Codec, handler core.HandlerFunc) core.Handl
 	}
 }
 
-func BytesPerFrame(codec *core.Codec) byte {
-	channels := byte(codec.Channels)
-	if channels == 0 {
-		channels = 1
-	}
-
+func BytesPerSample(codec *core.Codec) int {
 	switch codec.Name {
 	case core.CodecPCML, core.CodecPCM:
-		return 2 * channels
+		return 2
 	case core.CodecPCMU, core.CodecPCMA:
-		return channels
+		return 1
 	}
-
 	return 0
 }
+
+func BytesPerFrame(codec *core.Codec) int {
+	if codec.Channels <= 1 {
+		return BytesPerSample(codec)
+	}
+	return int(codec.Channels) * BytesPerSample(codec)
+}
+
+func FramesPerDuration(codec *core.Codec, duration time.Duration) int {
+	return int(time.Duration(codec.ClockRate) * duration / time.Second)
+}
+
+func BytesPerDuration(codec *core.Codec, duration time.Duration) int {
+	return BytesPerFrame(codec) * FramesPerDuration(codec, duration)
+}

pkg/pcm/pcm.go

@@ -1,13 +1,25 @@
 package pcm
 
-import "github.com/AlexxIT/go2rtc/pkg/core"
+import (
+	"math"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+func ceil(x float32) int {
+	d, fract := math.Modf(float64(x))
+	if fract == 0.0 {
+		return int(d)
+	}
+	return int(d) + 1
+}
 
 func Downsample(k float32) func([]int16) []int16 {
 	var sampleN, sampleSum float32
 
 	return func(src []int16) (dst []int16) {
 		var i int
-		dst = make([]int16, int((float32(len(src))+sampleN)/k))
+		dst = make([]int16, ceil((float32(len(src))+sampleN)/k))
 		for _, sample := range src {
 			sampleSum += float32(sample)
 			sampleN++
@@ -28,7 +40,7 @@ func Upsample(k float32) func([]int16) []int16 {
 
 	return func(src []int16) (dst []int16) {
 		var i int
-		dst = make([]int16, int(k*float32(len(src))))
+		dst = make([]int16, ceil(k*float32(len(src))))
 		for _, sample := range src {
 			sampleN += k
 			for sampleN > 0 {
@@ -185,3 +197,24 @@ func Transcode(dst, src *core.Codec) func([]byte) []byte {
 		return writer(samples)
 	}
 }
+
+func ConsumerCodecs() []*core.Codec {
+	return []*core.Codec{
+		{Name: core.CodecPCML},
+		{Name: core.CodecPCM},
+		{Name: core.CodecPCMA},
+		{Name: core.CodecPCMU},
+	}
+}
+
+func ProducerCodecs() []*core.Codec {
+	return []*core.Codec{
+		{Name: core.CodecPCML, ClockRate: 16000},
+		{Name: core.CodecPCM, ClockRate: 16000},
+		{Name: core.CodecPCML, ClockRate: 8000},
+		{Name: core.CodecPCM, ClockRate: 8000},
+		{Name: core.CodecPCMA, ClockRate: 8000},
+		{Name: core.CodecPCMU, ClockRate: 8000},
+		{Name: core.CodecPCML, ClockRate: 22050}, // wyoming-snd-external
+	}
+}

pkg/pcm/producer_sync.go

@@ -0,0 +1,96 @@
+package pcm
+
+import (
+	"io"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+type ProducerSync struct {
+	core.Connection
+	src     *core.Codec
+	rd      io.Reader
+	onClose func()
+}
+
+func OpenSync(codec *core.Codec, rd io.Reader) *ProducerSync {
+	medias := []*core.Media{
+		{
+			Kind:      core.KindAudio,
+			Direction: core.DirectionRecvonly,
+			Codecs:    ProducerCodecs(),
+		},
+	}
+
+	return &ProducerSync{
+		Connection: core.Connection{
+			ID:         core.NewID(),
+			FormatName: "pcm",
+			Medias:     medias,
+			Transport:  rd,
+		},
+		src: codec,
+		rd:  rd,
+	}
+}
+
+func (p *ProducerSync) OnClose(f func()) {
+	p.onClose = f
+}
+
+func (p *ProducerSync) Start() error {
+	if len(p.Receivers) == 0 {
+		return nil
+	}
+
+	var pktSeq uint16
+	var pktTS uint32          // time in frames
+	var pktTime time.Duration // time in seconds
+
+	t0 := time.Now()
+
+	dst := p.Receivers[0].Codec
+	transcode := Transcode(dst, p.src)
+
+	const chunkDuration = 20 * time.Millisecond
+	chunkBytes := BytesPerDuration(p.src, chunkDuration)
+	chunkFrames := uint32(FramesPerDuration(dst, chunkDuration))
+
+	for {
+		buf := make([]byte, chunkBytes)
+		n, _ := io.ReadFull(p.rd, buf)
+
+		if n == 0 {
+			break
+		}
+
+		pkt := &core.Packet{
+			Header: rtp.Header{
+				Version:        2,
+				Marker:         true,
+				SequenceNumber: pktSeq,
+				Timestamp:      pktTS,
+			},
+			Payload: transcode(buf[:n]),
+		}
+
+		if d := pktTime - time.Since(t0); d > 0 {
+			time.Sleep(d)
+		}
+
+		p.Receivers[0].WriteRTP(pkt)
+		p.Recv += n
+
+		pktSeq++
+		pktTS += chunkFrames
+		pktTime += chunkDuration
+	}
+
+	if p.onClose != nil {
+		p.onClose()
+	}
+
+	return nil
+}

pkg/pcm/s16le/s16le.go

@@ -0,0 +1,42 @@
+package s16le
+
+func PeaksRMS(b []byte) int16 {
+	// RMS of sine wave = peak / sqrt2
+	// https://en.wikipedia.org/wiki/Root_mean_square
+	// https://www.youtube.com/watch?v=MUDkL4KZi0I
+	var peaks int32
+	var peaksSum int32
+	var prevSample int16
+	var prevUp bool
+
+	var i int
+	for n := len(b); i < n; {
+		lo := b[i]
+		i++
+		hi := b[i]
+		i++
+
+		sample := int16(hi)<<8 | int16(lo)
+		up := sample >= prevSample
+
+		if i >= 4 {
+			if up != prevUp {
+				if prevSample >= 0 {
+					peaksSum += int32(prevSample)
+				} else {
+					peaksSum -= int32(prevSample)
+				}
+				peaks++
+			}
+		}
+
+		prevSample = sample
+		prevUp = up
+	}
+
+	if peaks == 0 {
+		return 0
+	}
+
+	return int16(peaksSum / peaks)
+}

pkg/stdin/backchannel.go

@@ -1,59 +0,0 @@
-package stdin
-
-import (
-	"encoding/json"
-
-	"github.com/AlexxIT/go2rtc/pkg/core"
-	"github.com/pion/rtp"
-)
-
-func (c *Client) GetMedias() []*core.Media {
-	return c.medias
-}
-
-func (c *Client) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
-	return nil, core.ErrCantGetTrack
-}
-
-func (c *Client) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiver) error {
-	if c.sender == nil {
-		stdin, err := c.cmd.StdinPipe()
-		if err != nil {
-			return err
-		}
-
-		c.sender = core.NewSender(media, track.Codec)
-		c.sender.Handler = func(packet *rtp.Packet) {
-			_, _ = stdin.Write(packet.Payload)
-			c.send += len(packet.Payload)
-		}
-	}
-
-	c.sender.HandleRTP(track)
-	return nil
-}
-
-func (c *Client) Start() (err error) {
-	return c.cmd.Run()
-}
-
-func (c *Client) Stop() (err error) {
-	if c.sender != nil {
-		c.sender.Close()
-	}
-	return c.cmd.Close()
-}
-
-func (c *Client) MarshalJSON() ([]byte, error) {
-	info := &core.Connection{
-		ID:         core.ID(c),
-		FormatName: "exec",
-		Protocol:   "pipe",
-		Medias:     c.medias,
-		Send:       c.send,
-	}
-	if c.sender != nil {
-		info.Senders = []*core.Sender{c.sender}
-	}
-	return json.Marshal(info)
-}

pkg/stdin/client.go

@@ -1,33 +0,0 @@
-package stdin
-
-import (
-	"github.com/AlexxIT/go2rtc/pkg/core"
-	"github.com/AlexxIT/go2rtc/pkg/shell"
-)
-
-// Deprecated: should be rewritten to core.Connection
-type Client struct {
-	cmd *shell.Command
-
-	medias []*core.Media
-	sender *core.Sender
-	send   int
-}
-
-func NewClient(cmd *shell.Command) (*Client, error) {
-	c := &Client{
-		cmd: cmd,
-		medias: []*core.Media{
-			{
-				Kind:      core.KindAudio,
-				Direction: core.DirectionSendonly,
-				Codecs: []*core.Codec{
-					{Name: core.CodecPCMA, ClockRate: 8000},
-					{Name: core.CodecPCM},
-				},
-			},
-		},
-	}
-
-	return c, nil
-}

pkg/wav/backchannel.go

@@ -0,0 +1,67 @@
+package wav
+
+import (
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/shell"
+	"github.com/pion/rtp"
+)
+
+type Backchannel struct {
+	core.Connection
+	cmd *shell.Command
+}
+
+func NewBackchannel(cmd *shell.Command) (core.Producer, error) {
+	medias := []*core.Media{
+		{
+			Kind:      core.KindAudio,
+			Direction: core.DirectionSendonly,
+			Codecs: []*core.Codec{
+				//{Name: core.CodecPCML},
+				{Name: core.CodecPCMA},
+				{Name: core.CodecPCMU},
+			},
+		},
+	}
+
+	return &Backchannel{
+		Connection: core.Connection{
+			ID:         core.NewID(),
+			FormatName: "wav",
+			Protocol:   "pipe",
+			Medias:     medias,
+			Transport:  cmd,
+		},
+		cmd: cmd,
+	}, nil
+}
+
+func (c *Backchannel) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
+	return nil, core.ErrCantGetTrack
+}
+
+func (c *Backchannel) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
+	wr, err := c.cmd.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	b := Header(track.Codec)
+	if _, err = wr.Write(b); err != nil {
+		return err
+	}
+
+	sender := core.NewSender(media, track.Codec)
+	sender.Handler = func(packet *rtp.Packet) {
+		if n, err := wr.Write(packet.Payload); err != nil {
+			c.Send += n
+		}
+	}
+	sender.HandleRTP(track)
+	c.Senders = append(c.Senders, sender)
+	return nil
+}
+
+func (c *Backchannel) Start() error {
+	return c.cmd.Run()
+}

pkg/wav/producer.go

@@ -2,7 +2,6 @@ package wav
 
 import (
 	"bufio"
-	"encoding/binary"
 	"errors"
 	"io"
 
@@ -17,39 +16,11 @@ func Open(r io.Reader) (*Producer, error) {
 	// https://www.mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
 	rd := bufio.NewReaderSize(r, core.BufferSize)
 
-	// skip Master RIFF chunk
-	if _, err := rd.Discard(12); err != nil {
+	codec, err := ReadHeader(r)
+	if err != nil {
 		return nil, err
 	}
 
-	codec := &core.Codec{}
-
-	for {
-		chunkID, data, err := readChunk(rd)
-		if err != nil {
-			return nil, err
-		}
-
-		if chunkID == "data" {
-			break
-		}
-
-		if chunkID == "fmt " {
-			// https://audiocoding.cc/articles/2008-05-22-wav-file-structure/wav_formats.txt
-			switch data[0] {
-			case 1:
-				codec.Name = core.CodecPCML
-			case 6:
-				codec.Name = core.CodecPCMA
-			case 7:
-				codec.Name = core.CodecPCMU
-			}
-
-			codec.Channels = data[2]
-			codec.ClockRate = binary.LittleEndian.Uint32(data[4:])
-		}
-	}
-
 	if codec.Name == "" {
 		return nil, errors.New("waw: unsupported codec")
 	}
@@ -110,18 +81,3 @@ func (c *Producer) Start() error {
 		ts += PacketSize
 	}
 }
-
-func readChunk(r io.Reader) (chunkID string, data []byte, err error) {
-	b := make([]byte, 8)
-	if _, err = io.ReadFull(r, b); err != nil {
-		return
-	}
-
-	if chunkID = string(b[:4]); chunkID != "data" {
-		size := binary.LittleEndian.Uint32(b[4:])
-		data = make([]byte, size)
-		_, err = io.ReadFull(r, data)
-	}
-
-	return
-}

pkg/wav/wav.go

@@ -0,0 +1,103 @@
+package wav
+
+import (
+	"encoding/binary"
+	"io"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+func Header(codec *core.Codec) []byte {
+	var fmt, size, extra byte
+
+	switch codec.Name {
+	case core.CodecPCML:
+		fmt = 1
+		size = 2
+	case core.CodecPCMA:
+		fmt = 6
+		size = 1
+		extra = 2
+	case core.CodecPCMU:
+		fmt = 7
+		size = 1
+		extra = 2
+	default:
+		return nil
+	}
+
+	channels := byte(codec.Channels)
+	if channels == 0 {
+		channels = 1
+	}
+
+	b := make([]byte, 0, 46) // cap with extra
+	b = append(b, "RIFF\xFF\xFF\xFF\xFFWAVEfmt "...)
+
+	b = append(b, 0x10+extra, 0, 0, 0)
+	b = append(b, fmt, 0)
+	b = append(b, channels, 0)
+	b = binary.LittleEndian.AppendUint32(b, codec.ClockRate)
+	b = binary.LittleEndian.AppendUint32(b, uint32(size*channels)*codec.ClockRate)
+	b = append(b, size*channels, 0)
+	b = append(b, size*8, 0)
+	if extra > 0 {
+		b = append(b, 0, 0) // ExtraParamSize (if PCM, then doesn't exist)
+	}
+
+	b = append(b, "data\xFF\xFF\xFF\xFF"...)
+
+	return b
+}
+
+func ReadHeader(r io.Reader) (*core.Codec, error) {
+	// skip Master RIFF chunk
+	if _, err := io.ReadFull(r, make([]byte, 12)); err != nil {
+		return nil, err
+	}
+
+	var codec core.Codec
+
+	for {
+		chunkID, data, err := readChunk(r)
+		if err != nil {
+			return nil, err
+		}
+
+		if chunkID == "data" {
+			break
+		}
+
+		if chunkID == "fmt " {
+			// https://audiocoding.cc/articles/2008-05-22-wav-file-structure/wav_formats.txt
+			switch data[0] {
+			case 1:
+				codec.Name = core.CodecPCML
+			case 6:
+				codec.Name = core.CodecPCMA
+			case 7:
+				codec.Name = core.CodecPCMU
+			}
+
+			codec.Channels = data[2]
+			codec.ClockRate = binary.LittleEndian.Uint32(data[4:])
+		}
+	}
+
+	return &codec, nil
+}
+
+func readChunk(r io.Reader) (chunkID string, data []byte, err error) {
+	b := make([]byte, 8)
+	if _, err = io.ReadFull(r, b); err != nil {
+		return
+	}
+
+	if chunkID = string(b[:4]); chunkID != "data" {
+		size := binary.LittleEndian.Uint32(b[4:])
+		data = make([]byte, size)
+		_, err = io.ReadFull(r, data)
+	}
+
+	return
+}

pkg/wyoming/README.md

@@ -0,0 +1,14 @@
+##  Default wake words
+
+- alexa_v0.1
+- hey_jarvis_v0.1
+- hey_mycroft_v0.1
+- hey_rhasspy_v0.1
+- ok_nabu_v0.1
+
+## Useful Links
+
+- https://github.com/rhasspy/wyoming-satellite
+- https://github.com/rhasspy/wyoming-openwakeword
+- https://github.com/fwartner/home-assistant-wakewords-collection
+- https://github.com/esphome/micro-wake-word-models/tree/main?tab=readme-ov-file

pkg/wyoming/api.go

@@ -0,0 +1,99 @@
+package wyoming
+
+import (
+	"bufio"
+	"encoding/json"
+	"io"
+	"net"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+type API struct {
+	conn net.Conn
+	rd   *bufio.Reader
+}
+
+func DialAPI(address string) (*API, error) {
+	conn, err := net.DialTimeout("tcp", address, core.ConnDialTimeout)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewAPI(conn), nil
+}
+
+const Version = "1.5.4"
+
+func NewAPI(conn net.Conn) *API {
+	return &API{conn: conn, rd: bufio.NewReader(conn)}
+}
+
+func (w *API) WriteEvent(evt *Event) (err error) {
+	hdr := EventHeader{
+		Type:          evt.Type,
+		Version:       Version,
+		DataLength:    len(evt.Data),
+		PayloadLength: len(evt.Payload),
+	}
+
+	buf, err := json.Marshal(hdr)
+	if err != nil {
+		return err
+	}
+
+	buf = append(buf, '\n')
+	buf = append(buf, evt.Data...)
+	buf = append(buf, evt.Payload...)
+
+	_, err = w.conn.Write(buf)
+	return err
+}
+
+func (w *API) ReadEvent() (*Event, error) {
+	data, err := w.rd.ReadBytes('\n')
+	if err != nil {
+		return nil, err
+	}
+
+	var hdr EventHeader
+	if err = json.Unmarshal(data, &hdr); err != nil {
+		return nil, err
+	}
+
+	evt := Event{Type: hdr.Type}
+
+	if hdr.DataLength > 0 {
+		data = make([]byte, hdr.DataLength)
+		if _, err = io.ReadFull(w.rd, data); err != nil {
+			return nil, err
+		}
+		evt.Data = string(data)
+	}
+
+	if hdr.PayloadLength > 0 {
+		evt.Payload = make([]byte, hdr.PayloadLength)
+		if _, err = io.ReadFull(w.rd, evt.Payload); err != nil {
+			return nil, err
+		}
+	}
+
+	return &evt, nil
+}
+
+func (w *API) Close() error {
+	return w.conn.Close()
+}
+
+type Event struct {
+	Type    string
+	Data    string
+	Payload []byte
+}
+
+type EventHeader struct {
+	Type          string `json:"type"`
+	Version       string `json:"version"`
+	DataLength    int    `json:"data_length,omitempty"`
+	PayloadLength int    `json:"payload_length,omitempty"`
+}

pkg/wyoming/backchannel.go

@@ -0,0 +1,63 @@
+package wyoming
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+type Backchannel struct {
+	core.Connection
+	api *API
+}
+
+func newBackchannel(conn net.Conn) *Backchannel {
+	return &Backchannel{
+		core.Connection{
+			ID:         core.NewID(),
+			FormatName: "wyoming",
+			Medias: []*core.Media{
+				{
+					Kind:      core.KindAudio,
+					Direction: core.DirectionSendonly,
+					Codecs: []*core.Codec{
+						{Name: core.CodecPCML, ClockRate: 22050},
+					},
+				},
+			},
+			Transport: conn,
+		},
+		NewAPI(conn),
+	}
+}
+
+func (b *Backchannel) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
+	return nil, core.ErrCantGetTrack
+}
+
+func (b *Backchannel) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
+	sender := core.NewSender(media, codec)
+	sender.Handler = func(pkt *rtp.Packet) {
+		ts := time.Now().Nanosecond()
+		evt := &Event{
+			Type:    "audio-chunk",
+			Data:    fmt.Sprintf(`{"rate":22050,"width":2,"channels":1,"timestamp":%d}`, ts),
+			Payload: pkt.Payload,
+		}
+		_ = b.api.WriteEvent(evt)
+	}
+	sender.HandleRTP(track)
+	b.Senders = append(b.Senders, sender)
+	return nil
+}
+
+func (b *Backchannel) Start() error {
+	for {
+		if _, err := b.api.ReadEvent(); err != nil {
+			return err
+		}
+	}
+}

pkg/wyoming/expr.go

@@ -0,0 +1,138 @@
+package wyoming
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/AlexxIT/go2rtc/pkg/expr"
+	"github.com/AlexxIT/go2rtc/pkg/wav"
+)
+
+type env struct {
+	*satellite
+	Type string
+	Data string
+}
+
+func (s *satellite) handleEvent(evt *Event) {
+	switch evt.Type {
+	case "describe":
+		// {"asr": [], "tts": [], "handle": [], "intent": [], "wake": [], "satellite": {"name": "my satellite", "attribution": {"name": "", "url": ""}, "installed": true, "description": "my satellite", "version": "1.4.1", "area": null, "snd_format": null}}
+		data := fmt.Sprintf(`{"satellite":{"name":%q,"attribution":{"name":"go2rtc","url":"https://github.com/AlexxIT/go2rtc"},"installed":true}}`, s.srv.Name)
+		s.WriteEvent("info", data)
+	case "run-satellite":
+		s.Detect()
+	case "pause-satellite":
+		s.Stop()
+	case "detect": // WAKE_WORD_START {"names": null}
+	case "detection": // WAKE_WORD_END {"name": "ok_nabu_v0.1", "timestamp": 17580, "speaker": null}
+	case "transcribe": // STT_START {"language": "en"}
+	case "voice-started": // STT_VAD_START {"timestamp": 1160}
+	case "voice-stopped": // STT_VAD_END {"timestamp": 2470}
+		s.Pause()
+	case "transcript": // STT_END {"text": "how are you"}
+	case "synthesize": // TTS_START {"text": "Sorry, I couldn't understand that", "voice": {"language": "en"}}
+	case "audio-start": // TTS_END {"rate": 22050, "width": 2, "channels": 1, "timestamp": 0}
+	case "audio-chunk": // {"rate": 22050, "width": 2, "channels": 1, "timestamp": 0}
+	case "audio-stop": // {"timestamp": 2.880000000000002}
+		// run async because PlayAudio takes some time
+		go func() {
+			s.PlayAudio()
+			s.WriteEvent("played")
+			s.Detect()
+		}()
+	case "error":
+		s.Detect()
+	case "internal-run":
+		s.WriteEvent("run-pipeline", `{"start_stage":"wake","end_stage":"tts"}`)
+		s.Stream()
+	case "internal-detection":
+		s.WriteEvent("run-pipeline", `{"start_stage":"asr","end_stage":"tts"}`)
+		s.Stream()
+	}
+}
+
+func (s *satellite) handleScript(evt *Event) {
+	var script string
+	if s.srv.Event != nil {
+		script = s.srv.Event[evt.Type]
+	}
+
+	s.srv.Trace("event=%s data=%s payload size=%d", evt.Type, evt.Data, len(evt.Payload))
+
+	if script == "" {
+		s.handleEvent(evt)
+		return
+	}
+
+	// run async because script can have sleeps
+	go func() {
+		e := &env{satellite: s, Type: evt.Type, Data: evt.Data}
+		if res, err := expr.Eval(script, e); err != nil {
+			s.srv.Trace("event=%s expr error=%s", evt.Type, err)
+			s.handleEvent(evt)
+		} else {
+			s.srv.Trace("event=%s expr result=%v", evt.Type, res)
+		}
+	}()
+}
+
+func (s *satellite) Detect() bool {
+	return s.setMicState(stateWaitVAD)
+}
+
+func (s *satellite) Stream() bool {
+	return s.setMicState(stateActive)
+}
+
+func (s *satellite) Pause() bool {
+	return s.setMicState(stateIdle)
+}
+
+func (s *satellite) Stop() bool {
+	s.micStop()
+	return true
+}
+
+func (s *satellite) WriteEvent(args ...string) bool {
+	if len(args) == 0 {
+		return false
+	}
+	evt := &Event{Type: args[0]}
+	if len(args) > 1 {
+		evt.Data = args[1]
+	}
+	if err := s.api.WriteEvent(evt); err != nil {
+		return false
+	}
+	return true
+}
+
+func (s *satellite) PlayAudio() bool {
+	return s.playAudio(sndCodec, bytes.NewReader(s.sndAudio))
+}
+
+func (s *satellite) PlayFile(path string) bool {
+	f, err := os.Open(path)
+	if err != nil {
+		return false
+	}
+
+	codec, err := wav.ReadHeader(f)
+	if err != nil {
+		return false
+	}
+
+	return s.playAudio(codec, f)
+}
+
+func (e *env) Sleep(s string) bool {
+	d, err := time.ParseDuration(s)
+	if err != nil {
+		return false
+	}
+	time.Sleep(d)
+	return true
+}

pkg/wyoming/mic.go

@@ -0,0 +1,35 @@
+package wyoming
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+func (s *Server) HandleMic(conn net.Conn) {
+	defer conn.Close()
+
+	var closed core.Waiter
+	var timestamp int
+
+	api := NewAPI(conn)
+	mic := newMicConsumer(func(chunk []byte) {
+		data := fmt.Sprintf(`{"rate":16000,"width":2,"channels":1,"timestamp":%d}`, timestamp)
+		evt := &Event{Type: "audio-chunk", Data: data, Payload: chunk}
+		if err := api.WriteEvent(evt); err != nil {
+			closed.Done(nil)
+		}
+
+		timestamp += len(chunk) / 2
+	})
+	mic.RemoteAddr = api.conn.RemoteAddr().String()
+
+	if err := s.MicHandler(mic); err != nil {
+		s.Error("mic error: %s", err)
+		return
+	}
+
+	_ = closed.Wait()
+	_ = mic.Stop()
+}

pkg/wyoming/producer.go

@@ -0,0 +1,65 @@
+package wyoming
+
+import (
+	"net"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+type Producer struct {
+	core.Connection
+	api *API
+}
+
+func newProducer(conn net.Conn) *Producer {
+	return &Producer{
+		core.Connection{
+			ID:         core.NewID(),
+			FormatName: "wyoming",
+			Medias: []*core.Media{
+				{
+					Kind:      core.KindAudio,
+					Direction: core.DirectionRecvonly,
+					Codecs: []*core.Codec{
+						{Name: core.CodecPCML, ClockRate: 16000},
+					},
+				},
+			},
+			Transport: conn,
+		},
+		NewAPI(conn),
+	}
+}
+
+func (p *Producer) Start() error {
+	var seq uint16
+	var ts uint32
+
+	for {
+		evt, err := p.api.ReadEvent()
+		if err != nil {
+			return err
+		}
+
+		if evt.Type != "audio-chunk" {
+			continue
+		}
+
+		p.Recv += len(evt.Payload)
+
+		pkt := &core.Packet{
+			Header: rtp.Header{
+				Version:        2,
+				Marker:         true,
+				SequenceNumber: seq,
+				Timestamp:      ts,
+			},
+			Payload: evt.Payload,
+		}
+		p.Receivers[0].WriteRTP(pkt)
+
+		seq++
+		ts += uint32(len(evt.Payload) / 2)
+	}
+}

pkg/wyoming/satellite.go

@@ -0,0 +1,275 @@
+package wyoming
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
+	"github.com/AlexxIT/go2rtc/pkg/pcm/s16le"
+	"github.com/pion/rtp"
+)
+
+type Server struct {
+	Name  string
+	Event map[string]string
+
+	VADThreshold int16
+	WakeURI      string
+
+	MicHandler func(cons core.Consumer) error
+	SndHandler func(prod core.Producer) error
+
+	Trace func(format string, v ...any)
+	Error func(format string, v ...any)
+}
+
+func (s *Server) Serve(l net.Listener) error {
+	for {
+		conn, err := l.Accept()
+		if err != nil {
+			return err
+		}
+
+		go s.Handle(conn)
+	}
+}
+
+func (s *Server) Handle(conn net.Conn) {
+	api := NewAPI(conn)
+	sat := newSatellite(api, s)
+	defer sat.Close()
+
+	for {
+		evt, err := api.ReadEvent()
+		if err != nil {
+			return
+		}
+
+		switch evt.Type {
+		case "ping": // {"text": null}
+			_ = api.WriteEvent(&Event{Type: "pong", Data: evt.Data})
+		case "audio-start": // TTS_END {"rate": 22050, "width": 2, "channels": 1, "timestamp": 0}
+			sat.sndAudio = sat.sndAudio[:0]
+		case "audio-chunk": // {"rate": 22050, "width": 2, "channels": 1, "timestamp": 0}
+			sat.sndAudio = append(sat.sndAudio, evt.Payload...)
+		default:
+			sat.handleScript(evt)
+		}
+	}
+}
+
+// states like http.ConnState
+const (
+	stateError        = -2
+	stateClosed       = -1
+	stateNew          = 0
+	stateIdle         = 1
+	stateWaitVAD      = 2 // aka wait VAD
+	stateWaitWakeWord = 3
+	stateActive       = 4
+)
+
+type satellite struct {
+	api *API
+	srv *Server
+
+	micState int8
+	micTS    int
+	micMu    sync.Mutex
+	sndAudio []byte
+
+	mic  *micConsumer
+	wake *WakeWord
+}
+
+func newSatellite(api *API, srv *Server) *satellite {
+	sat := &satellite{api: api, srv: srv}
+	return sat
+}
+
+func (s *satellite) Close() error {
+	s.Stop()
+	return s.api.Close()
+}
+
+const wakeTimeout = 5 * 2 * 16000 // 5 seconds
+
+func (s *satellite) setMicState(state int8) bool {
+	s.micMu.Lock()
+	defer s.micMu.Unlock()
+
+	if s.micState == stateNew {
+		s.mic = newMicConsumer(s.onMicChunk)
+		s.mic.RemoteAddr = s.api.conn.RemoteAddr().String()
+		if err := s.srv.MicHandler(s.mic); err != nil {
+			s.micState = stateError
+			s.srv.Error("can't get mic: %w", err)
+			_ = s.api.Close()
+		} else {
+			s.micState = stateIdle
+		}
+	}
+
+	if s.micState < stateIdle {
+		return false
+	}
+
+	s.micState = state
+	s.micTS = 0
+	return true
+}
+
+func (s *satellite) micStop() {
+	s.micMu.Lock()
+
+	s.micState = stateClosed
+	if s.mic != nil {
+		_ = s.mic.Stop()
+		s.mic = nil
+	}
+	if s.wake != nil {
+		_ = s.wake.Close()
+		s.wake = nil
+	}
+
+	s.micMu.Unlock()
+}
+
+func (s *satellite) onMicChunk(chunk []byte) {
+	s.micMu.Lock()
+	defer s.micMu.Unlock()
+
+	if s.micState == stateIdle {
+		return
+	}
+
+	if s.micState == stateWaitVAD {
+		// tests show that values over 1000 are most likely speech
+		if s.srv.VADThreshold == 0 || s16le.PeaksRMS(chunk) > s.srv.VADThreshold {
+			if s.wake == nil && s.srv.WakeURI != "" {
+				s.wake, _ = DialWakeWord(s.srv.WakeURI)
+			}
+			if s.wake == nil {
+				// some problems with wake word - redirect to HA
+				s.micState = stateIdle
+				go s.handleScript(&Event{Type: "internal-run"})
+			} else {
+				s.micState = stateWaitWakeWord
+			}
+			s.micTS = 0
+		}
+	}
+
+	if s.micState == stateWaitWakeWord {
+		if s.wake.Detection != "" {
+			// check if wake word detected
+			s.micState = stateIdle
+			go s.handleScript(&Event{Type: "internal-detection", Data: `{"name":"` + s.wake.Detection + `"}`})
+		} else if err := s.wake.WriteChunk(chunk); err != nil {
+			// wake word service failed
+			s.micState = stateWaitVAD
+			_ = s.wake.Close()
+			s.wake = nil
+		} else if s.micTS > wakeTimeout {
+			// wake word detection timeout
+			s.micState = stateWaitVAD
+		}
+	} else if s.wake != nil {
+		_ = s.wake.Close()
+		s.wake = nil
+	}
+
+	if s.micState == stateActive {
+		data := fmt.Sprintf(`{"rate":16000,"width":2,"channels":1,"timestamp":%d}`, s.micTS)
+		evt := &Event{Type: "audio-chunk", Data: data, Payload: chunk}
+		_ = s.api.WriteEvent(evt)
+	}
+
+	s.micTS += len(chunk) / 2
+}
+
+func (s *satellite) playAudio(codec *core.Codec, rd io.Reader) bool {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	prod := pcm.OpenSync(codec, rd)
+	prod.OnClose(cancel)
+
+	if err := s.srv.SndHandler(prod); err != nil {
+		return false
+	} else {
+		<-ctx.Done()
+		return true
+	}
+}
+
+type micConsumer struct {
+	core.Connection
+	onData  func(chunk []byte)
+	onClose func()
+}
+
+func newMicConsumer(onData func(chunk []byte)) *micConsumer {
+	medias := []*core.Media{
+		{
+			Kind:      core.KindAudio,
+			Direction: core.DirectionSendonly,
+			Codecs:    pcm.ConsumerCodecs(),
+		},
+	}
+
+	return &micConsumer{
+		Connection: core.Connection{
+			ID:         core.NewID(),
+			FormatName: "wyoming",
+			Protocol:   "tcp",
+			Medias:     medias,
+		},
+		onData: onData,
+	}
+}
+
+func (c *micConsumer) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
+	src := track.Codec
+	dst := &core.Codec{
+		Name:      core.CodecPCML,
+		ClockRate: 16000,
+		Channels:  1,
+	}
+	sender := core.NewSender(media, dst)
+	sender.Handler = pcm.TranscodeHandler(dst, src,
+		repack(func(packet *core.Packet) {
+			c.onData(packet.Payload)
+		}),
+	)
+	sender.HandleRTP(track)
+	c.Senders = append(c.Senders, sender)
+	return nil
+}
+
+func (c *micConsumer) Stop() error {
+	if c.onClose != nil {
+		c.onClose()
+	}
+	return c.Connection.Stop()
+}
+
+func repack(handler core.HandlerFunc) core.HandlerFunc {
+	const PacketSize = 2 * 16000 / 50 // 20ms
+
+	var buf []byte
+
+	return func(pkt *rtp.Packet) {
+		buf = append(buf, pkt.Payload...)
+
+		for len(buf) >= PacketSize {
+			pkt = &core.Packet{Payload: buf[:PacketSize]}
+			buf = buf[PacketSize:]
+			handler(pkt)
+		}
+	}
+}

pkg/wyoming/snd.go

@@ -0,0 +1,40 @@
+package wyoming
+
+import (
+	"bytes"
+	"net"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
+)
+
+func (s *Server) HandleSnd(conn net.Conn) {
+	defer conn.Close()
+
+	var snd []byte
+
+	api := NewAPI(conn)
+	for {
+		evt, err := api.ReadEvent()
+		if err != nil {
+			return
+		}
+
+		s.Trace("event: %s data: %s payload: %d", evt.Type, evt.Data, len(evt.Payload))
+
+		switch evt.Type {
+		case "audio-start":
+			snd = snd[:0]
+		case "audio-chunk":
+			snd = append(snd, evt.Payload...)
+		case "audio-stop":
+			prod := pcm.OpenSync(sndCodec, bytes.NewReader(snd))
+			if err = s.SndHandler(prod); err != nil {
+				s.Error("snd error: %s", err)
+				return
+			}
+		}
+	}
+}
+
+var sndCodec = &core.Codec{Name: core.CodecPCML, ClockRate: 22050}

pkg/wyoming/wakeword.go

@@ -0,0 +1,120 @@
+package wyoming
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+)
+
+type WakeWord struct {
+	*API
+	names []string
+	send  int
+
+	Detection string
+}
+
+func DialWakeWord(rawURL string) (*WakeWord, error) {
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, err
+	}
+
+	api, err := DialAPI(u.Host)
+	if err != nil {
+		return nil, err
+	}
+
+	names := u.Query()["name"]
+	if len(names) == 0 {
+		names = []string{"ok_nabu_v0.1"}
+	}
+
+	wake := &WakeWord{API: api, names: names}
+	if err = wake.Start(); err != nil {
+		_ = wake.Close()
+		return nil, err
+	}
+
+	go wake.handle()
+	return wake, nil
+}
+
+func (w *WakeWord) handle() {
+	defer w.Close()
+
+	for {
+		evt, err := w.ReadEvent()
+		if err != nil {
+			return
+		}
+
+		if evt.Type == "detection" {
+			var data struct {
+				Name string `json:"name"`
+			}
+			if err = json.Unmarshal([]byte(evt.Data), &data); err != nil {
+				return
+			}
+			w.Detection = data.Name
+		}
+	}
+}
+
+//func (w *WakeWord) Describe() error {
+//	if err := w.WriteEvent(&Event{Type: "describe"}); err != nil {
+//		return err
+//	}
+//
+//	evt, err := w.ReadEvent()
+//	if err != nil {
+//		return err
+//	}
+//
+//	var info struct {
+//		Wake []struct {
+//			Models []struct {
+//				Name string `json:"name"`
+//			} `json:"models"`
+//		} `json:"wake"`
+//	}
+//	if err = json.Unmarshal(evt.Data, &info); err != nil {
+//		return err
+//	}
+//
+//	return nil
+//}
+
+func (w *WakeWord) Start() error {
+	msg := struct {
+		Names []string `json:"names"`
+	}{
+		Names: w.names,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	evt := &Event{Type: "detect", Data: string(data)}
+	if err := w.WriteEvent(evt); err != nil {
+		return err
+	}
+
+	evt = &Event{Type: "audio-start", Data: audioData(0)}
+	return w.WriteEvent(evt)
+}
+
+func (w *WakeWord) Close() error {
+	return w.conn.Close()
+}
+
+func (w *WakeWord) WriteChunk(payload []byte) error {
+	evt := &Event{Type: "audio-chunk", Data: audioData(w.send), Payload: payload}
+	w.send += len(payload)
+	return w.WriteEvent(evt)
+}
+
+func audioData(send int) string {
+	// timestamp in ms = send / 2 * 1000 / 16000 = send / 32
+	return fmt.Sprintf(`{"rate":16000,"width":2,"channels":1,"timestamp":%d}`, send/32)
+}

pkg/wyoming/wyoming.go

@@ -0,0 +1,26 @@
+package wyoming
+
+import (
+	"net"
+	"net/url"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+func Dial(rawURL string) (core.Producer, error) {
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.DialTimeout("tcp", u.Host, core.ConnDialTimeout)
+	if err != nil {
+		return nil, err
+	}
+
+	if u.Query().Get("backchannel") != "1" {
+		return newProducer(conn), nil
+	} else {
+		return newBackchannel(conn), nil
+	}
+}