Update version to 1.4.0

cmd/app/app.go

@@ -16,7 +16,7 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-var Version = "1.3.2"
+var Version = "1.4.0"
 var UserAgent = "go2rtc/" + Version
 
 var ConfigPath string

cmd/ffmpeg/ffmpeg.go

@@ -60,7 +60,8 @@ var defaults = map[string]string{
 	"h265":  "-c:v libx265 -g 50 -profile:v high -level:v 5.1 -preset:v superfast -tune:v zerolatency",
 	"mjpeg": "-c:v mjpeg -force_duplicated_matrix:v 1 -huffman:v 0 -pix_fmt:v yuvj420p",
 
-	"opus":       "-c:a libopus -ar:a 48000 -ac:a 2",
+	// https://ffmpeg.org/ffmpeg-codecs.html#libopus-1
+	"opus":       "-c:a libopus -ar:a 48000 -ac:a 2 -application:a voip -compression_level:a 0",
 	"pcmu":       "-c:a pcm_mulaw -ar:a 8000 -ac:a 1",
 	"pcmu/16000": "-c:a pcm_mulaw -ar:a 16000 -ac:a 1",
 	"pcmu/48000": "-c:a pcm_mulaw -ar:a 48000 -ac:a 1",
@@ -70,8 +71,7 @@ var defaults = map[string]string{
 	"aac":        "-c:a aac", // keep sample rate and channels
 	"aac/16000":  "-c:a aac -ar:a 16000 -ac:a 1",
 	"mp3":        "-c:a libmp3lame -q:a 8",
-	"pcm":        "-c:a pcm_s16be",
-	"pcm/8000":   "-c:a pcm_s16be -ar:a 8000 -ac:a 1",
+	"pcm":        "-c:a pcm_s16be -ar:a 8000 -ac:a 1",
 	"pcm/16000":  "-c:a pcm_s16be -ar:a 16000 -ac:a 1",
 	"pcm/48000":  "-c:a pcm_s16be -ar:a 48000 -ac:a 1",
 

cmd/hls/hls.go

@@ -10,6 +10,7 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/tcp"
 	"github.com/rs/zerolog/log"
 	"net/http"
+	"strings"
 	"sync"
 	"time"
 )
@@ -48,6 +49,9 @@ const keepalive = 5 * time.Second
 
 var sessions = map[string]*Session{}
 
+// once I saw 404 on MP4 segment, so better to use mutex
+var sessionsMu sync.RWMutex
+
 func handlerStream(w http.ResponseWriter, r *http.Request) {
 	// CORS important for Chromecast
 	w.Header().Set("Access-Control-Allow-Origin", "*")
@@ -128,11 +132,16 @@ segment.ts?id=` + sid + `&n=%d
 segment.ts?id=` + sid + `&n=%d`
 	}
 
+	sessionsMu.Lock()
 	sessions[sid] = session
+	sessionsMu.Unlock()
+
+	// Apple Safari can play FLAC codec, but fail it it in m3u8 playlist
+	codecs := strings.Replace(cons.MimeCodecs(), mp4.MimeFlac, mp4.MimeAAC, 1)
 
 	// bandwidth important for Safari, codecs useful for smooth playback
 	data := []byte(`#EXTM3U
-#EXT-X-STREAM-INF:BANDWIDTH=1000000,CODECS="` + cons.MimeCodecs() + `"
+#EXT-X-STREAM-INF:BANDWIDTH=1000000,CODECS="` + codecs + `"
 hls/playlist.m3u8?id=` + sid)
 
 	if _, err := w.Write(data); err != nil {
@@ -150,7 +159,9 @@ func handlerPlaylist(w http.ResponseWriter, r *http.Request) {
 	}
 
 	sid := r.URL.Query().Get("id")
+	sessionsMu.RLock()
 	session := sessions[sid]
+	sessionsMu.RUnlock()
 	if session == nil {
 		http.NotFound(w, r)
 		return
@@ -173,7 +184,9 @@ func handlerSegmentTS(w http.ResponseWriter, r *http.Request) {
 	}
 
 	sid := r.URL.Query().Get("id")
+	sessionsMu.RLock()
 	session := sessions[sid]
+	sessionsMu.RUnlock()
 	if session == nil {
 		http.NotFound(w, r)
 		return
@@ -212,7 +225,9 @@ func handlerInit(w http.ResponseWriter, r *http.Request) {
 	}
 
 	sid := r.URL.Query().Get("id")
+	sessionsMu.RLock()
 	session := sessions[sid]
+	sessionsMu.RUnlock()
 	if session == nil {
 		http.NotFound(w, r)
 		return
@@ -233,7 +248,9 @@ func handlerSegmentMP4(w http.ResponseWriter, r *http.Request) {
 	}
 
 	sid := r.URL.Query().Get("id")
+	sessionsMu.RLock()
 	session := sessions[sid]
+	sessionsMu.RUnlock()
 	if session == nil {
 		http.NotFound(w, r)
 		return

cmd/mp4/mp4.go

@@ -4,13 +4,11 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
-	"sync"
 	"time"
 
 	"github.com/AlexxIT/go2rtc/cmd/api"
 	"github.com/AlexxIT/go2rtc/cmd/app"
 	"github.com/AlexxIT/go2rtc/cmd/streams"
-	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/mp4"
 	"github.com/AlexxIT/go2rtc/pkg/tcp"
 	"github.com/rs/zerolog"
@@ -61,6 +59,7 @@ func handlerKeyframe(w http.ResponseWriter, r *http.Request) {
 
 	if err := stream.AddConsumer(cons); err != nil {
 		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
@@ -106,17 +105,15 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 	cons := &mp4.Consumer{
 		RemoteAddr: tcp.RemoteAddr(r),
 		UserAgent:  r.UserAgent(),
-		Medias:     core.ParseQuery(r.URL.Query()),
+		Medias:     mp4.ParseQuery(r.URL.Query()),
 	}
 
-	var mu sync.Mutex
 	cons.Listen(func(msg any) {
+		if exit == nil {
+			return
+		}
 		if data, ok := msg.([]byte); ok {
-			mu.Lock()
-			_, err := w.Write(data)
-			mu.Unlock()
-
-			if err != nil && exit != nil {
+			if _, err := w.Write(data); err != nil {
 				select {
 				case exit <- err:
 				default:
@@ -128,6 +125,7 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 
 	if err := stream.AddConsumer(cons); err != nil {
 		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
@@ -138,11 +136,13 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 	data, err := cons.Init()
 	if err != nil {
 		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
 	if _, err = w.Write(data); err != nil {
 		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
@@ -153,7 +153,10 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 		if i, _ := strconv.Atoi(s); i > 0 {
 			duration = time.AfterFunc(time.Second*time.Duration(i), func() {
 				if exit != nil {
-					exit <- nil
+					select {
+					case exit <- nil:
+					default:
+					}
 					exit = nil
 				}
 			})
@@ -161,6 +164,7 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 	}
 
 	err = <-exit
+	exit = nil
 
 	log.Trace().Err(err).Caller().Send()
 

cmd/mp4/ws.go

@@ -110,6 +110,12 @@ func parseMedias(codecs string, parseAudio bool) (medias []*core.Media) {
 		case mp4.MimeAAC:
 			codec := &core.Codec{Name: core.CodecAAC}
 			audios = append(audios, codec)
+		case mp4.MimeFlac:
+			audios = append(audios,
+				&core.Codec{Name: core.CodecPCMA},
+				&core.Codec{Name: core.CodecPCMU},
+				&core.Codec{Name: core.CodecPCM},
+			)
 		case mp4.MimeOpus:
 			codec := &core.Codec{Name: core.CodecOpus}
 			audios = append(audios, codec)

go.mod

@@ -16,6 +16,8 @@ require (
 	github.com/pion/stun v0.4.0
 	github.com/pion/webrtc/v3 v3.1.58
 	github.com/rs/zerolog v1.29.0
+	github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3
+	github.com/sigurn/crc8 v0.0.0-20220107193325-2243fe600f9f
 	github.com/stretchr/testify v1.8.2
 	github.com/tadglines/go-pkgs v0.0.0-20210623144937-b983b20f54f9
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -106,6 +106,10 @@ github.com/rs/xid v1.4.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
 github.com/rs/zerolog v1.29.0 h1:Zes4hju04hjbvkVkOhdl2HpZa+0PmVwigmo8XoORE5w=
 github.com/rs/zerolog v1.29.0/go.mod h1:NILgTygv/Uej1ra5XxGf82ZFSLk58MFGAUS2o6usyD0=
 github.com/sclevine/agouti v3.0.0+incompatible/go.mod h1:b4WX9W9L1sfQKXeJf1mUTLZKJ48R1S7H23Ji7oFO5Bw=
+github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3 h1:aQKxg3+2p+IFXXg97McgDGT5zcMrQoi0EICZs8Pgchs=
+github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3/go.mod h1:9/etS5gpQq9BJsJMWg1wpLbfuSnkm8dPF6FdW2JXVhA=
+github.com/sigurn/crc8 v0.0.0-20220107193325-2243fe600f9f h1:1R9KdKjCNSd7F8iGTxIpoID9prlYH8nuNYKt0XvweHA=
+github.com/sigurn/crc8 v0.0.0-20220107193325-2243fe600f9f/go.mod h1:vQhwQ4meQEDfahT5kd61wLAF5AAeh5ZPLVI4JJ/tYo8=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=

pkg/core/codec.go

@@ -99,9 +99,16 @@ func UnmarshalCodec(md *sdp.MediaDescription, payloadType string) *Codec {
 		case "8":
 			c.Name = CodecPCMA
 			c.ClockRate = 8000
+		case "10":
+			c.Name = CodecPCM
+			c.ClockRate = 44100
+			c.Channels = 2
+		case "11":
+			c.Name = CodecPCM
+			c.ClockRate = 44100
 		case "14":
 			c.Name = CodecMP3
-			c.ClockRate = 44100
+			c.ClockRate = 90000 // it's not real sample rate
 		case "26":
 			c.Name = CodecJPEG
 			c.ClockRate = 90000

pkg/core/core.go

@@ -27,7 +27,8 @@ const (
 	CodecMP3  = "MPA" // payload: 14, aka MPEG-1 Layer III
 	CodecPCM  = "L16" // Linear PCM
 
-	CodecELD = "ELD" // AAC-ELD
+	CodecELD  = "ELD" // AAC-ELD
+	CodecFLAC = "FLAC"
 
 	CodecAll = "ALL"
 	CodecAny = "ANY"

pkg/core/media.go

@@ -93,7 +93,7 @@ func GetKind(name string) string {
 	switch name {
 	case CodecH264, CodecH265, CodecVP8, CodecVP9, CodecAV1, CodecJPEG:
 		return KindVideo
-	case CodecPCMU, CodecPCMA, CodecAAC, CodecOpus, CodecG722, CodecMP3, CodecELD:
+	case CodecPCMU, CodecPCMA, CodecAAC, CodecOpus, CodecG722, CodecMP3, CodecPCM, CodecELD, CodecFLAC:
 		return KindAudio
 	}
 	return ""
@@ -136,6 +136,10 @@ func MarshalSDP(name string, medias []*Media) ([]byte, error) {
 		}
 		md.WithCodec(codec.PayloadType, name, codec.ClockRate, codec.Channels, codec.FmtpLine)
 
+		if media.ID != "" {
+			md.WithValueAttribute("control", media.ID)
+		}
+
 		sd.MediaDescriptions = append(sd.MediaDescriptions, md)
 	}
 

pkg/iso/atoms.go

@@ -32,6 +32,16 @@ const (
 	Mdat                        = "mdat"
 )
 
+const (
+	sampleIsNonSync  = 0x10000
+	sampleDependsOn1 = 0x1000000
+	sampleDependsOn2 = 0x2000000
+
+	SampleVideoIFrame    = sampleDependsOn2
+	SampleVideoNonIFrame = sampleDependsOn1 | sampleIsNonSync
+	SampleAudio          = sampleIsNonSync
+)
+
 func (m *Movie) WriteFileType() {
 	m.StartAtom(Ftyp)
 	m.WriteString("iso5")
@@ -250,7 +260,7 @@ func (m *Movie) WriteAudioTrack(id uint32, codec string, timescale uint32, chann
 	m.EndAtom() // TRAK
 }
 
-func (m *Movie) WriteMovieFragment(seq, tid, duration, size uint32, time uint64) {
+func (m *Movie) WriteMovieFragment(seq, tid, duration, size, flags uint32, time uint64) {
 	m.StartAtom(Moof)
 
 	m.StartAtom(MoofMfhd)
@@ -276,10 +286,10 @@ func (m *Movie) WriteMovieFragment(seq, tid, duration, size uint32, time uint64)
 			TfhdDefaultSampleFlags |
 			TfhdDefaultBaseIsMoof,
 	)
-	m.WriteUint32(tid)       // track id
-	m.WriteUint32(duration)  // default sample duration
-	m.WriteUint32(size)      // default sample size
-	m.WriteUint32(0x2000000) // default sample flags
+	m.WriteUint32(tid)      // track id
+	m.WriteUint32(duration) // default sample duration
+	m.WriteUint32(size)     // default sample size
+	m.WriteUint32(flags)    // default sample flags
 	m.EndAtom()
 
 	m.StartAtom(MoofTrafTfdt)
@@ -314,5 +324,4 @@ func (m *Movie) WriteData(b []byte) {
 	m.StartAtom(Mdat)
 	m.Write(b)
 	m.EndAtom()
-
 }

pkg/iso/codecs.go

@@ -2,6 +2,7 @@ package iso
 
 import (
 	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
 )
 
 func (m *Movie) WriteVideo(codec string, width, height uint16, conf []byte) {
@@ -46,9 +47,11 @@ func (m *Movie) WriteVideo(codec string, width, height uint16, conf []byte) {
 func (m *Movie) WriteAudio(codec string, channels uint16, sampleRate uint32, conf []byte) {
 	switch codec {
 	case core.CodecAAC, core.CodecMP3:
-		m.StartAtom("mp4a")
+		m.StartAtom("mp4a") // supported in all players and browsers
+	case core.CodecFLAC:
+		m.StartAtom("fLaC") // supported in all players and browsers
 	case core.CodecOpus:
-		m.StartAtom("Opus")
+		m.StartAtom("Opus") // supported in Chrome and Firefox
 	case core.CodecPCMU:
 		m.StartAtom("ulaw")
 	case core.CodecPCMA:
@@ -56,6 +59,11 @@ func (m *Movie) WriteAudio(codec string, channels uint16, sampleRate uint32, con
 	default:
 		panic("unsupported iso audio: " + codec)
 	}
+
+	if channels == 0 {
+		channels = 1
+	}
+
 	m.Skip(6)
 	m.WriteUint16(1)                    // data_reference_index
 	m.Skip(2)                           // version
@@ -72,6 +80,10 @@ func (m *Movie) WriteAudio(codec string, channels uint16, sampleRate uint32, con
 		m.WriteEsdsAAC(conf)
 	case core.CodecMP3:
 		m.WriteEsdsMP3()
+	case core.CodecFLAC:
+		m.StartAtom("dfLa")
+		m.Write(pcm.FLACHeader(false, sampleRate))
+		m.EndAtom()
 	case core.CodecOpus:
 		// don't know what means this magic
 		m.StartAtom("dOps")
@@ -106,6 +118,7 @@ func (m *Movie) WriteEsdsAAC(conf []byte) {
 	m.Skip(2) // es id
 	m.Skip(1) // es flags
 
+	// https://learn.microsoft.com/en-us/windows/win32/medfound/mpeg-4-file-sink#aac-audio
 	m.WriteBytes(4, 0x80, 0x80, 0x80, size4+header+size5)
 	m.WriteBytes(0x40) // object id
 	m.WriteBytes(0x15) // stream type
@@ -139,6 +152,7 @@ func (m *Movie) WriteEsdsMP3() {
 	m.Skip(2) // es id
 	m.Skip(1) // es flags
 
+	// https://learn.microsoft.com/en-us/windows/win32/medfound/mpeg-4-file-sink#mp3-audio
 	m.WriteBytes(4, 0x80, 0x80, 0x80, size4)
 	m.WriteBytes(0x6B) // object id
 	m.WriteBytes(0x15) // stream type

pkg/mp4/consumer.go

@@ -6,7 +6,9 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/h264"
 	"github.com/AlexxIT/go2rtc/pkg/h265"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
 	"github.com/pion/rtp"
+	"sync"
 )
 
 type Consumer struct {
@@ -19,6 +21,7 @@ type Consumer struct {
 	senders []*core.Sender
 
 	muxer *Muxer
+	mu    sync.Mutex
 	wait  byte
 
 	send int
@@ -52,7 +55,8 @@ func (c *Consumer) GetMedias() []*core.Media {
 func (c *Consumer) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiver) error {
 	trackID := byte(len(c.senders))
 
-	handler := core.NewSender(media, track.Codec)
+	codec := track.Codec.Clone()
+	handler := core.NewSender(media, codec)
 
 	switch track.Codec.Name {
 	case core.CodecH264:
@@ -70,10 +74,12 @@ func (c *Consumer) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiv
 				c.wait = waitNone
 			}
 
+			// important to use Mutex because right fragment order
+			c.mu.Lock()
 			buf := c.muxer.Marshal(trackID, packet)
 			c.Fire(buf)
-
 			c.send += len(buf)
+			c.mu.Unlock()
 		}
 
 		if track.Codec.IsRTP() {
@@ -97,46 +103,48 @@ func (c *Consumer) AddTrack(media *core.Media, _ *core.Codec, track *core.Receiv
 				c.wait = waitNone
 			}
 
+			c.mu.Lock()
 			buf := c.muxer.Marshal(trackID, packet)
 			c.Fire(buf)
-
 			c.send += len(buf)
+			c.mu.Unlock()
 		}
 
 		if track.Codec.IsRTP() {
 			handler.Handler = h265.RTPDepay(track.Codec, handler.Handler)
 		}
 
-	case core.CodecAAC:
-		handler.Handler = func(packet *rtp.Packet) {
-			if c.wait != waitNone {
-				return
-			}
-
-			buf := c.muxer.Marshal(trackID, packet)
-			c.Fire(buf)
-
-			c.send += len(buf)
-		}
-
-		if track.Codec.IsRTP() {
-			handler.Handler = aac.RTPDepay(handler.Handler)
-		}
-
-	case core.CodecOpus, core.CodecMP3, core.CodecPCMU, core.CodecPCMA:
-		handler.Handler = func(packet *rtp.Packet) {
-			if c.wait != waitNone {
-				return
-			}
-
-			buf := c.muxer.Marshal(trackID, packet)
-			c.Fire(buf)
-
-			c.send += len(buf)
-		}
-
 	default:
-		panic("unsupported codec")
+		handler.Handler = func(packet *rtp.Packet) {
+			if c.wait != waitNone {
+				return
+			}
+
+			c.mu.Lock()
+			buf := c.muxer.Marshal(trackID, packet)
+			c.Fire(buf)
+			c.send += len(buf)
+			c.mu.Unlock()
+		}
+
+		switch track.Codec.Name {
+		case core.CodecAAC:
+			if track.Codec.IsRTP() {
+				handler.Handler = aac.RTPDepay(handler.Handler)
+			}
+		case core.CodecOpus, core.CodecMP3: // no changes
+		case core.CodecPCMA, core.CodecPCMU, core.CodecPCM:
+			handler.Handler = pcm.FLACEncoder(track.Codec, handler.Handler)
+			codec.Name = core.CodecFLAC
+
+		default:
+			handler.Handler = nil
+		}
+	}
+
+	if handler.Handler == nil {
+		println("ERROR: MP4 unsupported codec: " + track.Codec.String())
+		return nil
 	}
 
 	handler.HandleRTP(track)

pkg/mp4/helpers.go

@@ -4,9 +4,45 @@ import "github.com/AlexxIT/go2rtc/pkg/core"
 
 // ParseQuery - like usual parse, but with mp4 param handler
 func ParseQuery(query map[string][]string) []*core.Media {
-	if query["mp4"] != nil {
-		cons := Consumer{}
-		return cons.GetMedias()
+	if v := query["mp4"]; len(v) != 0 {
+		medias := []*core.Media{
+			{
+				Kind:      core.KindVideo,
+				Direction: core.DirectionSendonly,
+				Codecs: []*core.Codec{
+					{Name: core.CodecH264},
+					{Name: core.CodecH265},
+				},
+			},
+			{
+				Kind:      core.KindAudio,
+				Direction: core.DirectionSendonly,
+				Codecs: []*core.Codec{
+					{Name: core.CodecAAC},
+				},
+			},
+		}
+
+		if v[0] == "" {
+			return medias // legacy
+		}
+
+		medias[1].Codecs = append(medias[1].Codecs,
+			&core.Codec{Name: core.CodecPCMA},
+			&core.Codec{Name: core.CodecPCMU},
+			&core.Codec{Name: core.CodecPCM},
+		)
+
+		if v[0] == "flac" {
+			return medias // modern browsers
+		}
+
+		medias[1].Codecs = append(medias[1].Codecs,
+			&core.Codec{Name: core.CodecOpus},
+			&core.Codec{Name: core.CodecMP3},
+		)
+
+		return medias // Chrome, FFmpeg, VLC
 	}
 
 	return core.ParseQuery(query)

pkg/mp4/muxer.go

@@ -15,12 +15,14 @@ type Muxer struct {
 	fragIndex uint32
 	dts       []uint64
 	pts       []uint32
+	codecs    []*core.Codec
 }
 
 const (
 	MimeH264 = "avc1.640029"
 	MimeH265 = "hvc1.1.6.L153.B0"
 	MimeAAC  = "mp4a.40.2"
+	MimeFlac = "flac"
 	MimeOpus = "opus"
 )
 
@@ -43,6 +45,8 @@ func (m *Muxer) MimeCodecs(codecs []*core.Codec) string {
 			s += MimeAAC
 		case core.CodecOpus:
 			s += MimeOpus
+		case core.CodecFLAC:
+			s += MimeFlac
 		}
 	}
 
@@ -108,14 +112,15 @@ func (m *Muxer) GetInit(codecs []*core.Codec) ([]byte, error) {
 				uint32(i+1), codec.Name, codec.ClockRate, codec.Channels, b,
 			)
 
-		case core.CodecOpus, core.CodecMP3, core.CodecPCMU, core.CodecPCMA:
+		case core.CodecOpus, core.CodecMP3, core.CodecPCMA, core.CodecPCMU, core.CodecPCM, core.CodecFLAC:
 			mv.WriteAudioTrack(
 				uint32(i+1), codec.Name, codec.ClockRate, codec.Channels, nil,
 			)
 		}
 
-		m.pts = append(m.pts, 0)
 		m.dts = append(m.dts, 0)
+		m.pts = append(m.pts, 0)
+		m.codecs = append(m.codecs, codec)
 	}
 
 	mv.StartAtom(iso.MoovMvex)
@@ -138,28 +143,49 @@ func (m *Muxer) Reset() {
 }
 
 func (m *Muxer) Marshal(trackID byte, packet *rtp.Packet) []byte {
-	// important before increment
-	time := m.dts[trackID]
+	codec := m.codecs[trackID]
+
+	duration := packet.Timestamp - m.pts[trackID]
+	m.pts[trackID] = packet.Timestamp
+
+	// minumum duration important for MSE in Apple Safari
+	if duration == 0 || duration > codec.ClockRate {
+		duration = codec.ClockRate/1000 + 1
+		m.pts[trackID] += duration
+	}
+
+	size := len(packet.Payload)
+
+	// flags important for Apple Finder video preview
+	var flags uint32
+	switch codec.Name {
+	case core.CodecH264:
+		if h264.IsKeyframe(packet.Payload) {
+			flags = iso.SampleVideoIFrame
+		} else {
+			flags = iso.SampleVideoNonIFrame
+		}
+	case core.CodecH265:
+		if h265.IsKeyframe(packet.Payload) {
+			flags = iso.SampleVideoIFrame
+		} else {
+			flags = iso.SampleVideoNonIFrame
+		}
+	default:
+		flags = iso.SampleAudio // not important
+	}
 
 	m.fragIndex++
 
-	var duration uint32
-	newTime := packet.Timestamp
-	if m.pts[trackID] > 0 {
-		duration = newTime - m.pts[trackID]
-		m.dts[trackID] += uint64(duration)
-	} else {
-		// important, or Safari will fail with first frame
-		duration = 1
-	}
-	m.pts[trackID] = newTime
-
-	mv := iso.NewMovie(1024 + len(packet.Payload))
+	mv := iso.NewMovie(1024 + size)
 	mv.WriteMovieFragment(
-		m.fragIndex, uint32(trackID+1), duration,
-		uint32(len(packet.Payload)), time,
+		m.fragIndex, uint32(trackID+1), duration, uint32(size), flags, m.dts[trackID],
 	)
 	mv.WriteData(packet.Payload)
 
+	//log.Printf("[MP4] track=%d ts=%6d dur=%5d idx=%3d len=%d", trackID+1, m.dts[trackID], duration, m.fragIndex, len(packet.Payload))
+
+	m.dts[trackID] += uint64(duration)
+
 	return mv.Bytes()
 }

pkg/pcm/flac.go

@@ -0,0 +1,146 @@
+// Package pcm - support raw (verbatim) PCM 16 bit in the FLAC container:
+// - only 1 channel
+// - only 16 bit per sample
+// - only 8000, 16000, 24000, 48000 sample rate
+package pcm
+
+import (
+	"encoding/binary"
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+	"github.com/sigurn/crc16"
+	"github.com/sigurn/crc8"
+	"unicode/utf8"
+)
+
+func FLACHeader(magic bool, sampleRate uint32) []byte {
+	b := make([]byte, 42)
+
+	if magic {
+		copy(b, "fLaC") // [0..3]
+	}
+
+	// https://xiph.org/flac/format.html#metadata_block_header
+	b[4] = 0x80 // [4] lastMetadata=1 (1 bit), blockType=0 - STREAMINFO (7 bit)
+	b[7] = 0x22 // [5..7] blockLength=34 (24 bit)
+
+	// Important for Apple QuickTime player:
+	// 1. Both values should be same
+	// 2. Maximum value = 32768
+	binary.BigEndian.PutUint16(b[8:], 32768)  // [8..9] info.BlockSizeMin=16 (16 bit)
+	binary.BigEndian.PutUint16(b[10:], 32768) // [10..11] info.BlockSizeMin=65535 (16 bit)
+
+	// [12..14] info.FrameSizeMin=0 (24 bit)
+	// [15..17] info.FrameSizeMax=0 (24 bit)
+
+	b[18] = byte(sampleRate >> 12)
+	b[19] = byte(sampleRate >> 4)
+	b[20] = byte(sampleRate << 4) // [18..20] info.SampleRate=8000 (20 bit), info.NChannels=1-1 (3 bit)
+
+	b[21] = 0xF0 // [21..25] info.BitsPerSample=16-1 (5 bit), info.NSamples (36 bit)
+
+	// [26..41] MD5sum (16 bytes)
+
+	return b
+}
+
+var table8 *crc8.Table
+var table16 *crc16.Table
+
+func FLACEncoder(codec *core.Codec, handler core.HandlerFunc) core.HandlerFunc {
+	if codec.Channels >= 2 {
+		return nil
+	}
+
+	var sr byte
+	switch codec.ClockRate {
+	case 8000:
+		sr = 0b0100
+	case 16000:
+		sr = 0b0101
+	case 22050:
+		sr = 0b0110
+	case 24000:
+		sr = 0b0111
+	case 32000:
+		sr = 0b1000
+	case 44100:
+		sr = 0b1001
+	case 48000:
+		sr = 0b1010
+	case 96000:
+		sr = 0b1011
+	default:
+		return nil
+	}
+
+	if table8 == nil {
+		table8 = crc8.MakeTable(crc8.CRC8)
+	}
+	if table16 == nil {
+		table16 = crc16.MakeTable(crc16.CRC16_BUYPASS)
+	}
+
+	var sampleNumber int32
+
+	return func(packet *rtp.Packet) {
+		samples := uint16(len(packet.Payload))
+
+		if codec.Name == core.CodecPCM {
+			samples /= 2
+		}
+
+		// https://xiph.org/flac/format.html#frame_header
+		buf := make([]byte, samples*2+30)
+
+		// 1. Frame header
+		buf[0] = 0xFF
+		buf[1] = 0xF9      // [0..1] syncCode=0xFFF8 - reserved (15 bit), blockStrategy=1 - variable-blocksize (1 bit)
+		buf[2] = 0x70 | sr // blockSizeType=7 (4 bit), sampleRate=4 - 8000 (4 bit)
+		buf[3] = 0x08      // channels=1-1 (4 bit), sampleSize=4 - 16 (3 bit), reserved=0 (1 bit)
+
+		n := 4 + utf8.EncodeRune(buf[4:], sampleNumber) // 4 bytes max
+		sampleNumber += int32(samples)
+
+		// this is wrong but very simple frame block size value
+		binary.BigEndian.PutUint16(buf[n:], samples-1)
+		n += 2
+
+		buf[n] = crc8.Checksum(buf[:n], table8)
+		n += 1
+
+		// 2. Subframe header
+		buf[n] = 0x02 // padding=0 (1 bit), subframeType=1 - verbatim (6 bit), wastedFlag=0 (1 bit)
+		n += 1
+
+		// 3. Subframe
+		switch codec.Name {
+		case core.CodecPCMA:
+			for _, b := range packet.Payload {
+				s16 := PCMAtoPCM(b)
+				buf[n] = byte(s16 >> 8)
+				buf[n+1] = byte(s16)
+				n += 2
+			}
+		case core.CodecPCMU:
+			for _, b := range packet.Payload {
+				s16 := PCMUtoPCM(b)
+				buf[n] = byte(s16 >> 8)
+				buf[n+1] = byte(s16)
+				n += 2
+			}
+		case core.CodecPCM:
+			n += copy(buf[n:], packet.Payload)
+		}
+
+		// 4. Frame footer
+		crc := crc16.Checksum(buf[:n], table16)
+		binary.BigEndian.PutUint16(buf[n:], crc)
+		n += 2
+
+		clone := *packet
+		clone.Payload = buf[:n]
+
+		handler(&clone)
+	}
+}

pkg/pcm/pcm.go

@@ -0,0 +1,116 @@
+package pcm
+
+import (
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+)
+
+func Resample(codec *core.Codec, sampleRate uint32, handler core.HandlerFunc) core.HandlerFunc {
+	n := float32(codec.ClockRate) / float32(sampleRate)
+
+	switch codec.Name {
+	case core.CodecPCMA:
+		return DownsampleByte(PCMAtoPCM, PCMtoPCMA, n, handler)
+	case core.CodecPCMU:
+		return DownsampleByte(PCMUtoPCM, PCMtoPCMU, n, handler)
+	case core.CodecPCM:
+		if n == 1 {
+			return ResamplePCM(PCMtoPCMA, handler)
+		}
+		return DownsamplePCM(PCMtoPCMA, n, handler)
+	}
+
+	panic(core.Caller())
+}
+
+func DownsampleByte(
+	toPCM func(byte) int16, fromPCM func(int16) byte, n float32, handler core.HandlerFunc,
+) core.HandlerFunc {
+	var sampleN, sampleSum float32
+	var ts uint32
+
+	return func(packet *rtp.Packet) {
+		samples := len(packet.Payload)
+		newLen := uint32((float32(samples) + sampleN) / n)
+
+		oldSamples := packet.Payload
+		newSamples := make([]byte, newLen)
+
+		var i int
+		for _, sample := range oldSamples {
+			sampleSum += float32(toPCM(sample))
+			if sampleN++; sampleN >= n {
+				newSamples[i] = fromPCM(int16(sampleSum / n))
+				i++
+
+				sampleSum = 0
+				sampleN -= n
+			}
+		}
+
+		ts += newLen
+
+		clone := *packet
+		clone.Payload = newSamples
+		clone.Timestamp = ts
+		handler(&clone)
+	}
+}
+
+func ResamplePCM(fromPCM func(int16) byte, handler core.HandlerFunc) core.HandlerFunc {
+	var ts uint32
+
+	return func(packet *rtp.Packet) {
+		len1 := len(packet.Payload)
+		len2 := len1 / 2
+
+		oldSamples := packet.Payload
+		newSamples := make([]byte, len2)
+
+		var i2 int
+		for i1 := 0; i1 < len1; i1 += 2 {
+			sample := int16(uint16(oldSamples[i1])<<8 | uint16(oldSamples[i1+1]))
+			newSamples[i2] = fromPCM(sample)
+			i2++
+		}
+
+		ts += uint32(len2)
+
+		clone := *packet
+		clone.Payload = newSamples
+		clone.Timestamp = ts
+		handler(&clone)
+	}
+}
+
+func DownsamplePCM(fromPCM func(int16) byte, n float32, handler core.HandlerFunc) core.HandlerFunc {
+	var sampleN, sampleSum float32
+	var ts uint32
+
+	return func(packet *rtp.Packet) {
+		samples := len(packet.Payload) / 2
+		newLen := uint32((float32(samples) + sampleN) / n)
+
+		oldSamples := packet.Payload
+		newSamples := make([]byte, newLen)
+
+		var i2 int
+		for i1 := 0; i1 < len(packet.Payload); i1 += 2 {
+			sampleSum += float32(int16(uint16(oldSamples[i1])<<8 | uint16(oldSamples[i1+1])))
+			if sampleN++; sampleN >= n {
+				newSamples[i2] = fromPCM(int16(sampleSum / n))
+				i2++
+
+				sampleSum = 0
+				sampleN -= n
+			}
+		}
+
+		ts += newLen
+
+		clone := *packet
+		clone.Payload = newSamples
+		clone.Timestamp = ts
+		handler(&clone)
+	}
+}

pkg/pcm/pcma.go

@@ -0,0 +1,53 @@
+// Package pcm
+// https://www.codeproject.com/Articles/14237/Using-the-G711-standard
+package pcm
+
+const alawMax = 0x7FFF
+
+func PCMAtoPCM(alaw byte) int16 {
+	alaw ^= 0xD5
+
+	data := int16(((alaw & 0x0F) << 4) + 8)
+	exponent := (alaw & 0x70) >> 4
+
+	if exponent != 0 {
+		data |= 0x100
+	}
+
+	if exponent > 1 {
+		data <<= exponent - 1
+	}
+
+	// sign
+	if alaw&0x80 == 0 {
+		return data
+	} else {
+		return -data
+	}
+}
+
+func PCMtoPCMA(pcm int16) byte {
+	var alaw byte
+
+	if pcm < 0 {
+		pcm = -pcm
+		alaw = 0x80
+	}
+
+	if pcm > alawMax {
+		pcm = alawMax
+	}
+
+	exponent := byte(7)
+	for expMask := int16(0x4000); (pcm&expMask) == 0 && exponent > 0; expMask >>= 1 {
+		exponent--
+	}
+
+	if exponent == 0 {
+		alaw |= byte(pcm>>4) & 0x0F
+	} else {
+		alaw |= (exponent << 4) | (byte(pcm>>(exponent+3)) & 0x0F)
+	}
+
+	return alaw ^ 0xD5
+}

pkg/pcm/pcmu.go

@@ -0,0 +1,51 @@
+// Package pcm
+// https://www.codeproject.com/Articles/14237/Using-the-G711-standard
+package pcm
+
+const bias = 0x84 // 132 or 1000 0100
+const ulawMax = alawMax - bias
+
+func PCMUtoPCM(ulaw byte) int16 {
+	ulaw = ^ulaw
+
+	exponent := (ulaw & 0x70) >> 4
+	data := (int16((((ulaw&0x0F)|0x10)<<1)+1) << (exponent + 2)) - bias
+
+	// sign
+	if ulaw&0x80 == 0 {
+		return data
+	} else if data == 0 {
+		return -1
+	} else {
+		return -data
+	}
+}
+
+func PCMtoPCMU(pcm int16) byte {
+	var ulaw byte
+
+	if pcm < 0 {
+		pcm = -pcm
+		ulaw = 0x80
+	}
+
+	if pcm > ulawMax {
+		pcm = ulawMax
+	}
+
+	pcm += bias
+
+	exponent := byte(7)
+	for expMask := int16(0x4000); (pcm & expMask) == 0; expMask >>= 1 {
+		exponent--
+	}
+
+	// mantisa
+	ulaw |= byte(pcm>>(exponent+3)) & 0x0F
+
+	if exponent > 0 {
+		ulaw |= exponent << 4
+	}
+
+	return ^ulaw
+}

pkg/pcm/v1/pcm.go

@@ -0,0 +1,155 @@
+// Package v1
+// http://web.archive.org/web/20110719132013/http://hazelware.luggle.com/tutorials/mulawcompression.html
+package v1
+
+const cBias = 0x84
+const cClip = 32635
+
+var MuLawCompressTable = [256]byte{
+	0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+}
+
+func LinearToMuLawSample(sample int16) byte {
+	sign := byte(sample>>8) & 0x80
+	if sign != 0 {
+		sample = -sample
+	}
+
+	if sample > cClip {
+		sample = cClip
+	}
+	sample = sample + cBias
+
+	exponent := MuLawCompressTable[(sample>>7)&0xFF]
+	mantissa := byte(sample>>(exponent+3)) & 0x0F
+
+	compressedByte := ^(sign | (exponent << 4) | mantissa)
+
+	return compressedByte
+}
+
+var ALawCompressTable = [128]byte{
+	1, 1, 2, 2, 3, 3, 3, 3,
+	4, 4, 4, 4, 4, 4, 4, 4,
+	5, 5, 5, 5, 5, 5, 5, 5,
+	5, 5, 5, 5, 5, 5, 5, 5,
+	6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6,
+	6, 6, 6, 6, 6, 6, 6, 6,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7,
+}
+
+func LinearToALawSample(sample int16) byte {
+	sign := byte((^sample)>>8) & 0x80
+	if sign == 0 {
+		sample = -sample
+	}
+
+	if sample > cClip {
+		sample = cClip
+	}
+
+	var compressedByte byte
+	if sample >= 256 {
+		exponent := ALawCompressTable[(sample>>8)&0x7F]
+		mantissa := byte(sample>>(exponent+3)) & 0x0F
+		compressedByte = (exponent << 4) | mantissa
+	} else {
+		compressedByte = byte(sample >> 4)
+	}
+	compressedByte ^= sign ^ 0x55
+	return compressedByte
+}
+
+var MuLawDecompressTable = [256]int16{
+	-32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956,
+	-23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764,
+	-15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412,
+	-11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316,
+	-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
+	-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
+	-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
+	-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
+	-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
+	-1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
+	-876, -844, -812, -780, -748, -716, -684, -652,
+	-620, -588, -556, -524, -492, -460, -428, -396,
+	-372, -356, -340, -324, -308, -292, -276, -260,
+	-244, -228, -212, -196, -180, -164, -148, -132,
+	-120, -112, -104, -96, -88, -80, -72, -64,
+	-56, -48, -40, -32, -24, -16, -8, -1,
+	32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956,
+	23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
+	15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412,
+	11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316,
+	7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140,
+	5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092,
+	3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004,
+	2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980,
+	1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436,
+	1372, 1308, 1244, 1180, 1116, 1052, 988, 924,
+	876, 844, 812, 780, 748, 716, 684, 652,
+	620, 588, 556, 524, 492, 460, 428, 396,
+	372, 356, 340, 324, 308, 292, 276, 260,
+	244, 228, 212, 196, 180, 164, 148, 132,
+	120, 112, 104, 96, 88, 80, 72, 64,
+	56, 48, 40, 32, 24, 16, 8, 0,
+}
+
+var ALawDecompressTable = [256]int16{
+	-5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
+	-7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
+	-2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
+	-3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
+	-22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944,
+	-30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136,
+	-11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472,
+	-15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568,
+	-344, -328, -376, -360, -280, -264, -312, -296,
+	-472, -456, -504, -488, -408, -392, -440, -424,
+	-88, -72, -120, -104, -24, -8, -56, -40,
+	-216, -200, -248, -232, -152, -136, -184, -168,
+	-1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
+	-1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
+	-688, -656, -752, -720, -560, -528, -624, -592,
+	-944, -912, -1008, -976, -816, -784, -880, -848,
+	5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,
+	7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,
+	2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,
+	3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,
+	22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
+	30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
+	11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,
+	15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
+	344, 328, 376, 360, 280, 264, 312, 296,
+	472, 456, 504, 488, 408, 392, 440, 424,
+	88, 72, 120, 104, 24, 8, 56, 40,
+	216, 200, 248, 232, 152, 136, 184, 168,
+	1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,
+	1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,
+	688, 656, 752, 720, 560, 528, 624, 592,
+	944, 912, 1008, 976, 816, 784, 880, 848,
+}

pkg/pcm/v1/pcm_test.go

@@ -0,0 +1,39 @@
+package v1
+
+import (
+	v2 "github.com/AlexxIT/go2rtc/pkg/pcm"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestPCMUtoPCM(t *testing.T) {
+	for pcmu := byte(0); pcmu < 255; pcmu++ {
+		pcm1 := MuLawDecompressTable[pcmu]
+		pcm2 := v2.PCMUtoPCM(pcmu)
+		require.Equal(t, pcm1, pcm2)
+	}
+}
+
+func TestPCMAtoPCM(t *testing.T) {
+	for pcma := byte(0); pcma < 255; pcma++ {
+		pcm1 := ALawDecompressTable[pcma]
+		pcm2 := v2.PCMAtoPCM(pcma)
+		require.Equal(t, pcm1, pcm2)
+	}
+}
+
+func TestPCMtoPCMU(t *testing.T) {
+	for pcm := int16(-32768); pcm < 32767; pcm++ {
+		pcmu1 := LinearToMuLawSample(pcm)
+		pcmu2 := v2.PCMtoPCMU(pcm)
+		require.Equal(t, pcmu1, pcmu2)
+	}
+}
+
+func TestPCMtoPCMA(t *testing.T) {
+	for pcm := int16(-32768); pcm < 32767; pcm++ {
+		pcma1 := LinearToALawSample(pcm)
+		pcma2 := v2.PCMtoPCMA(pcm)
+		require.Equal(t, pcma1, pcma2)
+	}
+}

pkg/rtsp/client.go

@@ -288,6 +288,8 @@ func (c *Conn) Teardown() (err error) {
 }
 
 func (c *Conn) Close() error {
-	_ = c.Teardown()
+	if c.mode == core.ModeActiveProducer {
+		_ = c.Teardown()
+	}
 	return c.conn.Close()
 }

pkg/rtsp/consumer.go

@@ -58,21 +58,22 @@ func (c *Conn) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiv
 
 	// save original codec to sender (can have Codec.Name = ANY)
 	sender := core.NewSender(media, codec)
-	sender.Handler = c.packetWriter(codec, channel)
+	// important to send original codec for valid IsRTP check
+	sender.Handler = c.packetWriter(track.Codec, channel, codec.PayloadType)
 	sender.HandleRTP(track)
 
 	c.senders = append(c.senders, sender)
 	return nil
 }
 
-func (c *Conn) packetWriter(codec *core.Codec, channel uint8) core.HandlerFunc {
+func (c *Conn) packetWriter(codec *core.Codec, channel, payloadType uint8) core.HandlerFunc {
 	handlerFunc := func(packet *rtp.Packet) {
 		if c.state == StateNone {
 			return
 		}
 
 		clone := *packet
-		clone.Header.PayloadType = codec.PayloadType
+		clone.Header.PayloadType = payloadType
 
 		size := clone.MarshalSize()
 

pkg/rtsp/server.go

@@ -40,8 +40,9 @@ func (c *Conn) Accept() error {
 
 		if !c.auth.Validate(req) {
 			res := &tcp.Response{
-				Status: "401 Unauthorized",
-				Header: map[string][]string{"Www-Authenticate": {`Basic realm="go2rtc"`}},
+				Status:  "401 Unauthorized",
+				Header:  map[string][]string{"Www-Authenticate": {`Basic realm="go2rtc"`}},
+				Request: req,
 			}
 			if err = c.WriteResponse(res); err != nil {
 				return err

pkg/webrtc/consumer.go

@@ -5,11 +5,12 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/h264"
 	"github.com/AlexxIT/go2rtc/pkg/h265"
+	"github.com/AlexxIT/go2rtc/pkg/pcm"
 	"github.com/pion/rtp"
 )
 
 func (c *Conn) GetMedias() []*core.Media {
-	return c.medias
+	return WithResampling(c.medias)
 }
 
 func (c *Conn) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
@@ -31,15 +32,16 @@ func (c *Conn) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiv
 	}
 
 	localTrack := c.getTranseiver(media.ID).Sender().Track().(*Track)
+	payloadType := codec.PayloadType
 
-	sender := core.NewSender(media, track.Codec)
+	sender := core.NewSender(media, codec)
 	sender.Handler = func(packet *rtp.Packet) {
 		c.send += packet.MarshalSize()
 		//important to send with remote PayloadType
-		_ = localTrack.WriteRTP(codec.PayloadType, packet)
+		_ = localTrack.WriteRTP(payloadType, packet)
 	}
 
-	switch codec.Name {
+	switch track.Codec.Name {
 	case core.CodecH264:
 		sender.Handler = h264.RTPPay(1200, sender.Handler)
 		if track.Codec.IsRTP() {
@@ -55,6 +57,15 @@ func (c *Conn) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiv
 		if track.Codec.IsRTP() {
 			sender.Handler = h265.RTPDepay(track.Codec, sender.Handler)
 		}
+
+	case core.CodecPCMA, core.CodecPCMU, core.CodecPCM:
+		if codec.ClockRate == 0 {
+			if codec.Name == core.CodecPCM {
+				codec.Name = core.CodecPCMA
+			}
+			codec.ClockRate = 8000
+			sender.Handler = pcm.Resample(track.Codec, 8000, sender.Handler)
+		}
 	}
 
 	sender.HandleRTP(track)

pkg/webrtc/helpers.go

@@ -52,6 +52,53 @@ func UnmarshalMedias(descriptions []*sdp.MediaDescription) (medias []*core.Media
 	return
 }
 
+func WithResampling(medias []*core.Media) []*core.Media {
+	for _, media := range medias {
+		if media.Kind != core.KindAudio || media.Direction != core.DirectionSendonly {
+			continue
+		}
+
+		var pcma, pcmu, pcm *core.Codec
+
+		for _, codec := range media.Codecs {
+			switch codec.Name {
+			case core.CodecPCMA:
+				if codec.ClockRate != 0 {
+					pcma = codec
+				} else {
+					pcma = nil
+				}
+			case core.CodecPCMU:
+				if codec.ClockRate != 0 {
+					pcmu = codec
+				} else {
+					pcmu = nil
+				}
+			case core.CodecPCM:
+				pcm = codec
+			}
+		}
+
+		if pcma != nil {
+			pcma = pcma.Clone()
+			pcma.ClockRate = 0 // reset clock rate so will match any
+			media.Codecs = append(media.Codecs, pcma)
+		}
+		if pcmu != nil {
+			pcmu = pcmu.Clone()
+			pcmu.ClockRate = 0
+			media.Codecs = append(media.Codecs, pcmu)
+		}
+		if pcma != nil && pcm == nil {
+			pcm = pcma.Clone()
+			pcm.Name = core.CodecPCM
+			media.Codecs = append(media.Codecs, pcm)
+		}
+	}
+
+	return medias
+}
+
 func NewCandidate(network, address string) (string, error) {
 	i := strings.LastIndexByte(address, ':')
 	if i < 0 {

www/links.html

@@ -67,12 +67,14 @@
 
             <h2>H264/H265 source</h2>
             <li><a href="stream.html?src=${src}&mode=webrtc">stream.html</a> WebRTC stream / browsers: all / codecs: H264, PCMU, PCMA, OPUS / +H265 in Safari</li>
-            <li><a href="stream.html?src=${src}&mode=mse">stream.html</a> MSE stream / browsers: Chrome, Firefox, Safari Mac/iPad / codecs: H264, H265*, AAC / +OPUS in Chrome and Firefox</li>
-            <li><a href="api/stream.mp4?src=${src}">stream.mp4</a> MP4 stream with AAC audio / browsers: Chrome, Firefox / codecs: H264, H265*, AAC</li>
-            <li><a href="api/stream.mp4?src=${src}&video=h264,h265&audio=aac,opus,mp3,pcma,pcmu">stream.mp4</a> MP4 stream with any audio / browsers: Chrome / codecs: H264, H265*, AAC, OPUS, MP3, PCMU, PCMA</li>
+            <li><a href="stream.html?src=${src}&mode=mse">stream.html</a> MSE stream / browsers: Chrome, Firefox, Safari Mac/iPad / codecs: H264, H265*, AAC, PCMA*, PCMU*, PCM* / +OPUS in Chrome and Firefox</li>
+            <li><a href="api/stream.mp4?src=${src}">stream.mp4</a> legacy MP4 stream with AAC audio / browsers: Chrome, Firefox / codecs: H264, H265*, AAC</li>
+            <li><a href="api/stream.mp4?src=${src}&mp4=flac">stream.mp4</a> modern MP4 stream with common audio / browsers: Chrome, Firefox / codecs: H264, H265*, AAC, FLAC (PCMA, PCMU, PCM)</li>
+            <li><a href="api/stream.mp4?src=${src}&mp4=all">stream.mp4</a> MP4 stream with any audio / browsers: Chrome / codecs: H264, H265*, AAC, OPUS, MP3, FLAC (PCMA, PCMU, PCM)</li>
             <li><a href="api/frame.mp4?src=${src}">frame.mp4</a> snapshot in MP4-format / browsers: all / codecs: H264, H265*</li>
-            <li><a href="api/stream.m3u8?src=${src}">stream.m3u8</a> HLS/TS / browsers: Safari all, Chrome Android / codecs: H264</li>
-            <li><a href="api/stream.m3u8?src=${src}&mp4">stream.m3u8</a> HLS/fMP4 / browsers: Safari all, Chrome Android / codecs: H264, H265*, AAC</li>
+            <li><a href="api/stream.m3u8?src=${src}">stream.m3u8</a> legacy HLS/TS / browsers: Safari all, Chrome Android / codecs: H264</li>
+            <li><a href="api/stream.m3u8?src=${src}&mp4">stream.m3u8</a> legacy HLS/fMP4 / browsers: Safari all, Chrome Android / codecs: H264, H265*, AAC</li>
+            <li><a href="api/stream.m3u8?src=${src}&mp4=flac">stream.m3u8</a> modern HLS/fMP4 / browsers: Safari all, Chrome Android / codecs: H264, H265*, AAC, FLAC (PCMA, PCMU, PCM)</li>
 
             <h2>MJPEG source</h2>
             <li><a href="stream.html?src=${src}&mode=mjpeg">stream.html</a> with MJPEG mode / browsers: all / codecs: MJPEG, JPEG</li>

www/video-rtc.js

@@ -27,7 +27,8 @@ export class VideoRTC extends HTMLElement {
             "hvc1.1.6.L153.B0", // H.265 main 5.1 (Chromecast Ultra)
             "mp4a.40.2",        // AAC LC
             "mp4a.40.5",        // AAC HE
-            "opus",             // OPUS Chrome
+            "flac",             // FLAC (PCM compatible)
+            "opus",             // OPUS Chrome, Firefox
         ];
 
         /**