Add support OPUS inside MPEG-TS

pkg/bits/reader.go

@@ -127,3 +127,7 @@ func (r *Reader) ReadSEGolomb() int32 {
 		return int32(b >> 1)
 	}
 }
+
+func (r *Reader) Left() []byte {
+	return r.buf[r.pos:]
+}

pkg/mpegts/demuxer.go

@@ -1,6 +1,7 @@
 package mpegts
 
 import (
+	"bytes"
 	"errors"
 	"io"
 
@@ -98,6 +99,11 @@ func (d *Demuxer) skip(i byte) {
 	d.pos += i
 }
 
+func (d *Demuxer) readBytes(i byte) []byte {
+	d.pos += i
+	return d.buf[d.pos-i : d.pos]
+}
+
 func (d *Demuxer) readPSIHeader() {
 	// https://en.wikipedia.org/wiki/Program-specific_information#Table_Sections
 	pointer := d.readByte() // Pointer field
@@ -159,7 +165,11 @@ func (d *Demuxer) readPMT() {
 		_ = d.readBits(4)          // Reserved bits
 		_ = d.readBits(2)          // ES Info length unused bits
 		size = d.readBits(10)      // ES Info length
-		d.skip(byte(size))
+		info := d.readBytes(byte(size))
+
+		if streamType == StreamTypePrivate && bytes.HasPrefix(info, opusInfo) {
+			streamType = StreamTypePrivateOPUS
+		}
 
 		d.pes[pid] = &PES{StreamType: streamType}
 	}
@@ -175,7 +185,7 @@ func (d *Demuxer) readPES(pid uint16, start bool) *rtp.Packet {
 
 	// if new payload beging
 	if start {
-		if pes.Payload != nil {
+		if len(pes.Payload) != 0 {
 			d.pos = skipRead
 			return pes.GetPacket() // finish previous packet
 		}
@@ -314,12 +324,13 @@ const (
 
 // https://en.wikipedia.org/wiki/Program-specific_information#Elementary_stream_types
 const (
-	StreamTypeMetadata = 0    // Reserved
-	StreamTypePrivate  = 0x06 // PCMU or PCMA or FLAC from FFmpeg
-	StreamTypeAAC      = 0x0F
-	StreamTypeH264     = 0x1B
-	StreamTypeH265     = 0x24
-	StreamTypePCMATapo = 0x90
+	StreamTypeMetadata    = 0    // Reserved
+	StreamTypePrivate     = 0x06 // PCMU or PCMA or FLAC from FFmpeg
+	StreamTypeAAC         = 0x0F
+	StreamTypeH264        = 0x1B
+	StreamTypeH265        = 0x24
+	StreamTypePCMATapo    = 0x90
+	StreamTypePrivateOPUS = 0xEB
 )
 
 // PES - Packetized Elementary Stream
@@ -397,6 +408,23 @@ func (p *PES) GetPacket() (pkt *rtp.Packet) {
 		}
 
 		//p.Timestamp += uint32(len(p.Payload)) // update next timestamp!
+
+	case StreamTypePrivateOPUS:
+		p.Sequence++
+
+		pkt = &rtp.Packet{
+			Header: rtp.Header{
+				Version:        2,
+				Marker:         true,
+				PayloadType:    p.StreamType,
+				SequenceNumber: p.Sequence,
+				Timestamp:      p.PTS,
+			},
+		}
+
+		pkt.Payload, p.Payload = CutOPUSPacket(p.Payload)
+		p.PTS += opusDT
+		return
 	}
 
 	p.Payload = nil

pkg/mpegts/opus.go

@@ -0,0 +1,66 @@
+package mpegts
+
+import (
+	"github.com/AlexxIT/go2rtc/pkg/bits"
+)
+
+// opusDT - each AU from FFmpeg has 5 OPUS packets. Each packet len = 960 in the 48000 clock.
+const opusDT = 960 * ClockRate / 48000
+
+// https://opus-codec.org/docs/
+var opusInfo = []byte{ // registration_descriptor
+	0x05,               // descriptor_tag
+	0x04,               // descriptor_length
+	'O', 'p', 'u', 's', // format_identifier
+}
+
+//goland:noinspection GoSnakeCaseUsage
+func CutOPUSPacket(b []byte) (packet []byte, left []byte) {
+	r := bits.NewReader(b)
+
+	size := opus_control_header(r)
+	if size == 0 {
+		return nil, nil
+	}
+
+	packet = r.ReadBytes(size)
+	left = r.Left()
+	return
+}
+
+//goland:noinspection GoSnakeCaseUsage
+func opus_control_header(r *bits.Reader) int {
+	control_header_prefix := r.ReadBits(11)
+	if control_header_prefix != 0x3FF {
+		return 0
+	}
+
+	start_trim_flag := r.ReadBit()
+	end_trim_flag := r.ReadBit()
+	control_extension_flag := r.ReadBit()
+	_ = r.ReadBits(2) // reserved
+
+	var payload_size int
+	for {
+		i := r.ReadByte()
+		payload_size += int(i)
+		if i < 255 {
+			break
+		}
+	}
+
+	if start_trim_flag != 0 {
+		_ = r.ReadBits(3)
+		_ = r.ReadBits(13)
+	}
+	if end_trim_flag != 0 {
+		_ = r.ReadBits(3)
+		_ = r.ReadBits(13)
+	}
+	if control_extension_flag != 0 {
+		control_extension_length := r.ReadByte()
+		_ = r.ReadBytes(int(control_extension_length)) // reserved
+	}
+
+	return payload_size
+}

pkg/mpegts/producer.go

@@ -87,7 +87,7 @@ func (c *Producer) probe() error {
 		case StreamTypeMetadata:
 			for _, streamType := range pkt.Payload {
 				switch streamType {
-				case StreamTypeH264, StreamTypeH265, StreamTypeAAC:
+				case StreamTypeH264, StreamTypeH265, StreamTypeAAC, StreamTypePrivateOPUS:
 					waitType = append(waitType, streamType)
 				}
 			}
@@ -118,6 +118,19 @@ func (c *Producer) probe() error {
 				Codecs:    []*core.Codec{codec},
 			}
 			c.Medias = append(c.Medias, media)
+
+		case StreamTypePrivateOPUS:
+			codec := &core.Codec{
+				Name:      core.CodecOpus,
+				ClockRate: 48000,
+				Channels:  2,
+			}
+			media := &core.Media{
+				Kind:      core.KindAudio,
+				Direction: core.DirectionRecvonly,
+				Codecs:    []*core.Codec{codec},
+			}
+			c.Medias = append(c.Medias, media)
 		}
 	}
 
@@ -134,6 +147,8 @@ func StreamType(codec *core.Codec) uint8 {
 		return StreamTypeAAC
 	case core.CodecPCMA:
 		return StreamTypePCMATapo
+	case core.CodecOpus:
+		return StreamTypePrivateOPUS
 	}
 	return 0
 }