mpegts, srt: support MPEG-4 Audio LATM tracks (#4403) (#4759)

internal/formatprocessor/mpeg4_audio_latm.go

@@ -0,0 +1,114 @@
+package formatprocessor
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpfragmented"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpmpeg4audio"
+	"github.com/pion/rtp"
+
+	"github.com/bluenviron/mediamtx/internal/logger"
+	"github.com/bluenviron/mediamtx/internal/unit"
+)
+
+type mpeg4AudioLATM struct {
+	RTPMaxPayloadSize  int
+	Format             *format.MPEG4AudioLATM
+	GenerateRTPPackets bool
+	Parent             logger.Writer
+
+	encoder     *rtpfragmented.Encoder
+	decoder     *rtpfragmented.Decoder
+	randomStart uint32
+}
+
+func (t *mpeg4AudioLATM) initialize() error {
+	if t.GenerateRTPPackets {
+		err := t.createEncoder()
+		if err != nil {
+			return err
+		}
+
+		t.randomStart, err = randUint32()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (t *mpeg4AudioLATM) createEncoder() error {
+	t.encoder = &rtpfragmented.Encoder{
+		PayloadMaxSize: t.RTPMaxPayloadSize,
+		PayloadType:    t.Format.PayloadTyp,
+	}
+	return t.encoder.Init()
+}
+
+func (t *mpeg4AudioLATM) ProcessUnit(uu unit.Unit) error { //nolint:dupl
+	u := uu.(*unit.MPEG4AudioLATM)
+
+	pkts, err := t.encoder.Encode(u.Element)
+	if err != nil {
+		return err
+	}
+	u.RTPPackets = pkts
+
+	for _, pkt := range u.RTPPackets {
+		pkt.Timestamp += t.randomStart + uint32(u.PTS)
+	}
+
+	return nil
+}
+
+func (t *mpeg4AudioLATM) ProcessRTPPacket( //nolint:dupl
+	pkt *rtp.Packet,
+	ntp time.Time,
+	pts int64,
+	hasNonRTSPReaders bool,
+) (unit.Unit, error) {
+	u := &unit.MPEG4AudioLATM{
+		Base: unit.Base{
+			RTPPackets: []*rtp.Packet{pkt},
+			NTP:        ntp,
+			PTS:        pts,
+		},
+	}
+
+	// remove padding
+	pkt.Padding = false
+	pkt.PaddingSize = 0
+
+	if len(pkt.Payload) > t.RTPMaxPayloadSize {
+		return nil, fmt.Errorf("RTP payload size (%d) is greater than maximum allowed (%d)",
+			len(pkt.Payload), t.RTPMaxPayloadSize)
+	}
+
+	// decode from RTP
+	if hasNonRTSPReaders || t.decoder != nil {
+		if t.decoder == nil {
+			var err error
+			t.decoder, err = t.Format.CreateDecoder()
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		el, err := t.decoder.Decode(pkt)
+		if err != nil {
+			if errors.Is(err, rtpmpeg4audio.ErrMorePacketsNeeded) {
+				return u, nil
+			}
+			return nil, err
+		}
+
+		u.Element = el
+	}
+
+	// route packet as is
+	return u, nil
+}

internal/formatprocessor/mpeg4_video.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/bluenviron/gortsplib/v4/pkg/format"
-	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpmpeg4video"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpfragmented"
 	"github.com/bluenviron/mediacommon/v2/pkg/codecs/mpeg4video"
 	"github.com/pion/rtp"
 
@@ -33,8 +33,8 @@ type mpeg4Video struct {
 	GenerateRTPPackets bool
 	Parent             logger.Writer
 
-	encoder     *rtpmpeg4video.Encoder
-	decoder     *rtpmpeg4video.Decoder
+	encoder     *rtpfragmented.Encoder
+	decoder     *rtpfragmented.Decoder
 	randomStart uint32
 }
 
@@ -55,7 +55,7 @@ func (t *mpeg4Video) initialize() error {
 }
 
 func (t *mpeg4Video) createEncoder() error {
-	t.encoder = &rtpmpeg4video.Encoder{
+	t.encoder = &rtpfragmented.Encoder{
 		PayloadMaxSize: t.RTPMaxPayloadSize,
 		PayloadType:    t.Format.PayloadTyp,
 	}
@@ -154,7 +154,7 @@ func (t *mpeg4Video) ProcessRTPPacket( //nolint:dupl
 
 		frame, err := t.decoder.Decode(pkt)
 		if err != nil {
-			if errors.Is(err, rtpmpeg4video.ErrMorePacketsNeeded) {
+			if errors.Is(err, rtpfragmented.ErrMorePacketsNeeded) {
 				return u, nil
 			}
 			return nil, err

internal/formatprocessor/processor.go

@@ -135,6 +135,14 @@ func New(
 			Parent:             parent,
 		}
 
+	case *format.MPEG4AudioLATM:
+		proc = &mpeg4AudioLATM{
+			RTPMaxPayloadSize:  rtpMaxPayloadSize,
+			Format:             forma,
+			GenerateRTPPackets: generateRTPPackets,
+			Parent:             parent,
+		}
+
 	case *format.MPEG1Audio:
 		proc = &mpeg1Audio{
 			RTPMaxPayloadSize:  rtpMaxPayloadSize,