stream/mts: adding some constants

stream/mts/encoder.go

@@ -171,14 +171,6 @@ var (
 	pmtTable = standardPmtTimeLocation.Bytes()
 )
 
-const (
-	sdtPid   = 17
-	patPid   = 0
-	pmtPid   = 4096
-	videoPid = 256
-	streamID = 0xe0 // First video stream ID.
-)
-
 // Time related constants.
 const (
 	// ptsOffset is the offset added to the clock to determine
@@ -213,18 +205,13 @@ func NewEncoder(dst io.Writer, fps float64) *Encoder {
 		ptsOffset:     ptsOffset,
 
 		continuity: map[int]byte{
-			patPid:   0,
+			PatPid:   0,
-			pmtPid:   0,
+			PmtPid:   0,
-			videoPid: 0,
+			VideoPid: 0,
 		},
 	}
 }
 
-const (
-	hasPayload         = 0x1
-	hasAdaptationField = 0x2
-)
-
 const (
 	hasDTS = 0x1
 	hasPTS = 0x2
@@ -241,7 +228,7 @@ func (e *Encoder) Encode(nalu []byte) error {
 	}
 	// Prepare PES data.
 	pesPkt := pes.Packet{
-		StreamID:     streamID,
+		StreamID:     StreamID,
 		PDI:          hasPTS,
 		PTS:          e.pts(),
 		Data:         nalu,
@@ -253,10 +240,10 @@ func (e *Encoder) Encode(nalu []byte) error {
 	for len(buf) != 0 {
 		pkt := Packet{
 			PUSI: pusi,
-			PID:  videoPid,
+			PID:  VideoPid,
 			RAI:  pusi,
-			CC:   e.ccFor(videoPid),
+			CC:   e.ccFor(VideoPid),
-			AFC:  hasAdaptationField | hasPayload,
+			AFC:  HasAdaptationField | HasPayload,
 			PCRF: pusi,
 		}
 		n := pkt.FillPayload(buf)
@@ -286,9 +273,9 @@ func (e *Encoder) writePSI() error {
 	// Write PAT.
 	patPkt := Packet{
 		PUSI:    true,
-		PID:     patPid,
+		PID:     PatPid,
-		CC:      e.ccFor(patPid),
+		CC:      e.ccFor(PatPid),
-		AFC:     hasPayload,
+		AFC:     HasPayload,
 		Payload: patTable,
 	}
 	_, err := e.dst.Write(patPkt.Bytes(e.tsSpace[:PacketSize]))
@@ -309,9 +296,9 @@ func (e *Encoder) writePSI() error {
 	// Create mts packet from pmt table.
 	pmtPkt := Packet{
 		PUSI:    true,
-		PID:     pmtPid,
+		PID:     PmtPid,
-		CC:      e.ccFor(pmtPid),
+		CC:      e.ccFor(PmtPid),
-		AFC:     hasPayload,
+		AFC:     HasPayload,
 		Payload: pmtTable,
 	}
 	_, err = e.dst.Write(pmtPkt.Bytes(e.tsSpace[:PacketSize]))

stream/mts/mpegts.go

@@ -37,6 +37,53 @@ const (
 	PayloadSize = 176
 )
 
+const (
+	SdtPid                = 17
+	PatPid                = 0
+	PmtPid                = 4096
+	VideoPid              = 256
+	StreamID              = 0xe0 // First video stream ID.
+	HeadSize              = 4
+	DefaultAdaptationSize = 2
+)
+
+const (
+	AdaptationIdx             = 4
+	AdaptationControlIdx      = 3
+	AdaptationBodyIdx         = AdaptationIdx + 1
+	AdaptationControlMask     = 0x30
+	DefaultAdaptationBodySize = 1
+)
+
+const (
+	HasPayload         = 0x1
+	HasAdaptationField = 0x2
+)
+
+// Adaptation field body masks.
+const (
+	DiscontinuityIndicatorMask            = 0x80
+	RandomAccessIndicatorMask             = 0x40
+	ElementaryStreamPriorityIndicatorMask = 0x20
+	ProgramClockReferenceFlagMask         = 0x10
+	OriginalProgramClockReferenceFlagMask = 0x08
+	SplicingPointFlagMask                 = 0x04
+	TransportPrivateDataFlagMask          = 0x02
+	AdaptationFieldExtensionMask          = 0x01
+)
+
+// Adaptation field body indexes.
+const (
+	DiscontinuityIndicatorIdx            = AdaptationIdx + 1
+	RandomAccessIndicatorIdx             = AdaptationIdx + 1
+	ElementaryStreamPriorityIndicatorIdx = AdaptationIdx + 1
+	ProgramClockReferenceFlagIdx         = AdaptationIdx + 1
+	OriginalProgramClockReferenceFlagIdx = AdaptationIdx + 1
+	SplicingPointFlagIdx                 = AdaptationIdx + 1
+	TransportPrivateDataFlagIdx          = AdaptationIdx + 1
+	AdaptationFieldExtensionFlagIdx      = AdaptationIdx + 1
+)
+
 /*
 The below data struct encapsulates the fields of an MPEG-TS packet. Below is
 the formatting of an MPEG-TS packet for reference!
@@ -135,7 +182,7 @@ func FindPMT(d []byte) (p []byte, i int, err error) {
 	}
 	for i = 0; i < len(d); i += PacketSize {
 		pid := (uint16(d[i+1]&0x1f) << 8) | uint16(d[i+2])
-		if pid == pmtPid {
+		if pid == PmtPid {
 			p = d[i+4 : i+PacketSize]
 			return
 		}