support recording M-JPEG tracks (#2391)

internal/formatprocessor/mjpeg.go

@@ -0,0 +1,113 @@
+package formatprocessor //nolint:dupl
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpmjpeg"
+	"github.com/pion/rtp"
+
+	"github.com/bluenviron/mediamtx/internal/unit"
+)
+
+type formatProcessorMJPEG struct {
+	udpMaxPayloadSize int
+	format            *format.MJPEG
+	encoder           *rtpmjpeg.Encoder
+	decoder           *rtpmjpeg.Decoder
+}
+
+func newMJPEG(
+	udpMaxPayloadSize int,
+	forma *format.MJPEG,
+	generateRTPPackets bool,
+) (*formatProcessorMJPEG, error) {
+	t := &formatProcessorMJPEG{
+		udpMaxPayloadSize: udpMaxPayloadSize,
+		format:            forma,
+	}
+
+	if generateRTPPackets {
+		err := t.createEncoder()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return t, nil
+}
+
+func (t *formatProcessorMJPEG) createEncoder() error {
+	t.encoder = &rtpmjpeg.Encoder{
+		PayloadMaxSize: t.udpMaxPayloadSize - 12,
+	}
+	return t.encoder.Init()
+}
+
+func (t *formatProcessorMJPEG) ProcessUnit(uu unit.Unit) error { //nolint:dupl
+	u := uu.(*unit.MJPEG)
+
+	// encode into RTP
+	pkts, err := t.encoder.Encode(u.Frame)
+	if err != nil {
+		return err
+	}
+
+	ts := uint32(multiplyAndDivide(u.PTS, time.Duration(t.format.ClockRate()), time.Second))
+	for _, pkt := range pkts {
+		pkt.Timestamp += ts
+	}
+
+	u.RTPPackets = pkts
+
+	return nil
+}
+
+func (t *formatProcessorMJPEG) ProcessRTPPacket( //nolint:dupl
+	pkt *rtp.Packet,
+	ntp time.Time,
+	pts time.Duration,
+	hasNonRTSPReaders bool,
+) (Unit, error) {
+	u := &unit.MJPEG{
+		Base: unit.Base{
+			RTPPackets: []*rtp.Packet{pkt},
+			NTP:        ntp,
+			PTS:        pts,
+		},
+	}
+
+	// remove padding
+	pkt.Header.Padding = false
+	pkt.PaddingSize = 0
+
+	if pkt.MarshalSize() > t.udpMaxPayloadSize {
+		return nil, fmt.Errorf("payload size (%d) is greater than maximum allowed (%d)",
+			pkt.MarshalSize(), t.udpMaxPayloadSize)
+	}
+
+	// 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
+			}
+		}
+
+		frame, err := t.decoder.Decode(pkt)
+		if err != nil {
+			if err == rtpmjpeg.ErrNonStartingPacketAndNoPrevious || err == rtpmjpeg.ErrMorePacketsNeeded {
+				return u, nil
+			}
+			return nil, err
+		}
+
+		u.Frame = frame
+	}
+
+	// route packet as is
+	return u, nil
+}