From 69dd4d26eccd4daaa68394ee180a12898e19aa05 Mon Sep 17 00:00:00 2001
From: Alexey Khit <alexey.khit@gmail.com>
Date: Fri, 27 Jan 2023 17:11:44 +0300
Subject: [PATCH] Add support OPUS, MP3, PCMU, PCMA for MP4

---
 pkg/iso/codecs.go   | 72 +++++++++++++++++++++++++++++++--------------
 pkg/mp4/consumer.go |  3 +-
 pkg/mp4/muxer.go    |  2 +-
 3 files changed, 52 insertions(+), 25 deletions(-)

diff --git a/pkg/iso/codecs.go b/pkg/iso/codecs.go
index 07eeb379..ecb251d0 100644
--- a/pkg/iso/codecs.go
+++ b/pkg/iso/codecs.go
@@ -2,22 +2,13 @@ package iso
 
 import "github.com/AlexxIT/go2rtc/pkg/streamer"
 
-const (
-	MoovTrakMdiaMinfStblStsdAvc1     = "avc1"
-	MoovTrakMdiaMinfStblStsdAvc1AvcC = "avcC"
-	MoovTrakMdiaMinfStblStsdHev1     = "hev1"
-	MoovTrakMdiaMinfStblStsdHev1HvcC = "hvcC"
-	MoovTrakMdiaMinfStblStsdMp4a     = "mp4a"
-	MoovTrakMdiaMinfStblStsdOpus     = "Opus"
-)
-
 func (m *Movie) WriteVideo(codec string, width, height uint16, conf []byte) {
 	// https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap3/qtff3.html
 	switch codec {
 	case streamer.CodecH264:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdAvc1)
+		m.StartAtom("avc1")
 	case streamer.CodecH265:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdHev1)
+		m.StartAtom("hev1")
 	default:
 		panic("unsupported iso video: " + codec)
 	}
@@ -40,9 +31,9 @@ func (m *Movie) WriteVideo(codec string, width, height uint16, conf []byte) {
 
 	switch codec {
 	case streamer.CodecH264:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdAvc1AvcC)
+		m.StartAtom("avcC")
 	case streamer.CodecH265:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdHev1HvcC)
+		m.StartAtom("hvcC")
 	}
 	m.Write(conf)
 	m.EndAtom() // AVCC
@@ -52,10 +43,14 @@ 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 streamer.CodecAAC:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdMp4a)
+	case streamer.CodecAAC, streamer.CodecMP3:
+		m.StartAtom("mp4a")
 	case streamer.CodecOpus:
-		m.StartAtom(MoovTrakMdiaMinfStblStsdOpus)
+		m.StartAtom("Opus")
+	case streamer.CodecPCMU:
+		m.StartAtom("ulaw")
+	case streamer.CodecPCMA:
+		m.StartAtom("alaw")
 	default:
 		panic("unsupported iso audio: " + codec)
 	}
@@ -73,8 +68,18 @@ func (m *Movie) WriteAudio(codec string, channels uint16, sampleRate uint32, con
 	switch codec {
 	case streamer.CodecAAC:
 		m.WriteEsdsAAC(conf)
+	case streamer.CodecMP3:
+		m.WriteEsdsMP3()
 	case streamer.CodecOpus:
-		m.WriteDops()
+		// don't know what means this magic
+		m.StartAtom("dOps")
+		m.WriteBytes(0, 0x02, 0x01, 0x38, 0, 0, 0xBB, 0x80, 0, 0, 0)
+		m.EndAtom()
+	case streamer.CodecPCMU, streamer.CodecPCMA:
+		// don't know what means this magic
+		m.StartAtom("chan")
+		m.WriteBytes(0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0)
+		m.EndAtom()
 	}
 
 	m.EndAtom() // MP4A/OPUS
@@ -115,9 +120,32 @@ func (m *Movie) WriteEsdsAAC(conf []byte) {
 	m.EndAtom() // ESDS
 }
 
-func (m *Movie) WriteDops() {
-	// don't know what means this magic
-	m.StartAtom("dOps")
-	m.WriteBytes(0, 0x02, 0x01, 0x38, 0, 0, 0xBB, 0x80, 0, 0, 0)
-	m.EndAtom()
+func (m *Movie) WriteEsdsMP3() {
+	m.StartAtom("esds")
+	m.Skip(1) // version
+	m.Skip(3) // flags
+
+	// MP4ESDescrTag[3]:
+	// - MP4DecConfigDescrTag[4]:
+	// - Other[6]
+	const header = 5
+	const size3 = 3
+	const size4 = 13
+	const size6 = 1
+
+	m.WriteBytes(3, 0x80, 0x80, 0x80, size3+header+size4+header+size6)
+	m.Skip(2) // es id
+	m.Skip(1) // es flags
+
+	m.WriteBytes(4, 0x80, 0x80, 0x80, size4)
+	m.WriteBytes(0x6B) // object id
+	m.WriteBytes(0x15) // stream type
+	m.Skip(3)          // buffer size db
+	m.Skip(4)          // max bitraga
+	m.Skip(4)          // avg bitraga
+
+	m.WriteBytes(6, 0x80, 0x80, 0x80, 1)
+	m.WriteBytes(2) // ?
+
+	m.EndAtom() // ESDS
 }
diff --git a/pkg/mp4/consumer.go b/pkg/mp4/consumer.go
index 9f1f3b50..8d5fbf2d 100644
--- a/pkg/mp4/consumer.go
+++ b/pkg/mp4/consumer.go
@@ -50,7 +50,6 @@ func (c *Consumer) GetMedias() []*streamer.Media {
 			Direction: streamer.DirectionRecvonly,
 			Codecs: []*streamer.Codec{
 				{Name: streamer.CodecAAC},
-				{Name: streamer.CodecOpus},
 			},
 		},
 	}
@@ -143,7 +142,7 @@ func (c *Consumer) AddTrack(media *streamer.Media, track *streamer.Track) *strea
 
 		return track.Bind(push)
 
-	case streamer.CodecOpus:
+	case streamer.CodecOpus, streamer.CodecMP3, streamer.CodecPCMU, streamer.CodecPCMA:
 		push := func(packet *rtp.Packet) error {
 			if c.wait != waitNone {
 				return nil
diff --git a/pkg/mp4/muxer.go b/pkg/mp4/muxer.go
index 2d944b0e..83bb33c5 100644
--- a/pkg/mp4/muxer.go
+++ b/pkg/mp4/muxer.go
@@ -108,7 +108,7 @@ func (m *Muxer) GetInit(codecs []*streamer.Codec) ([]byte, error) {
 				uint32(i+1), codec.Name, codec.ClockRate, codec.Channels, b,
 			)
 
-		case streamer.CodecOpus:
+		case streamer.CodecOpus, streamer.CodecMP3, streamer.CodecPCMU, streamer.CodecPCMA:
 			mv.WriteAudioTrack(
 				uint32(i+1), codec.Name, codec.ClockRate, codec.Channels, nil,
 			)