first commit

format/mp4f/mp4fio/mp4io.go

@@ -0,0 +1,113 @@
+package mp4fio
+
+import (
+	"github.com/deepch/vdk/format/mp4/mp4io"
+	"github.com/deepch/vdk/utils/bits/pio"
+)
+
+type ElemStreamDesc struct {
+	DecConfig []byte
+	TrackId   uint16
+	mp4io.AtomPos
+}
+
+func (self ElemStreamDesc) Children() []mp4io.Atom {
+	return nil
+}
+
+func (self ElemStreamDesc) fillLength(b []byte, length int) (n int) {
+	b[n] = uint8(length & 0x7f)
+	n++
+	return
+}
+
+func (self ElemStreamDesc) lenDescHdr() (n int) {
+	return 2
+}
+
+func (self ElemStreamDesc) fillDescHdr(b []byte, tag uint8, datalen int) (n int) {
+	b[n] = tag
+	n++
+	n += self.fillLength(b[n:], datalen)
+	return
+}
+
+func (self ElemStreamDesc) lenESDescHdr() (n int) {
+	return self.lenDescHdr() + 3
+}
+
+func (self ElemStreamDesc) fillESDescHdr(b []byte, datalen int) (n int) {
+	n += self.fillDescHdr(b[n:], mp4io.MP4ESDescrTag, datalen)
+	pio.PutU16BE(b[n:], self.TrackId)
+	n += 2
+	b[n] = 0 // flags
+	n++
+	return
+}
+
+func (self ElemStreamDesc) lenDecConfigDescHdr() (n int) {
+	return self.lenDescHdr() + 2 + 3 + 4 + 4 + self.lenDescHdr()
+}
+
+func (self ElemStreamDesc) fillDecConfigDescHdr(b []byte, datalen int) (n int) {
+	n += self.fillDescHdr(b[n:], mp4io.MP4DecConfigDescrTag, datalen)
+	b[n] = 0x40 // objectid
+	n++
+	b[n] = 0x15 // streamtype
+	n++
+	// buffer size db
+	pio.PutU24BE(b[n:], 0)
+	n += 3
+	// max bitrage
+	pio.PutU32BE(b[n:], uint32(200000))
+	n += 4
+	// avg bitrage
+	pio.PutU32BE(b[n:], uint32(0))
+	n += 4
+	n += self.fillDescHdr(b[n:], mp4io.MP4DecSpecificDescrTag, datalen-n)
+	return
+}
+
+func (self ElemStreamDesc) Len() (n int) {
+	// len + tag
+	return 8 +
+		// ver + flags
+		4 +
+		self.lenESDescHdr() +
+		self.lenDecConfigDescHdr() +
+		len(self.DecConfig) +
+		self.lenDescHdr() + 1
+}
+
+// Version(4)
+// ESDesc(
+//   MP4ESDescrTag
+//   ESID(2)
+//   ESFlags(1)
+//   DecConfigDesc(
+//     MP4DecConfigDescrTag
+//     objectId streamType bufSize avgBitrate
+//     DecSpecificDesc(
+//       MP4DecSpecificDescrTag
+//       decConfig
+//     )
+//   )
+//   ?Desc(lenDescHdr+1)
+// )
+
+func (self ElemStreamDesc) Marshal(b []byte) (n int) {
+	pio.PutU32BE(b[4:], uint32(mp4io.ESDS))
+	n += 8
+	pio.PutU32BE(b[n:], 0) // Version
+	n += 4
+	datalen := self.Len()
+	n += self.fillESDescHdr(b[n:], datalen-n-self.lenESDescHdr()+3)
+	n += self.fillDecConfigDescHdr(b[n:], datalen-n-self.lenDescHdr()-3)
+	copy(b[n:], self.DecConfig)
+	n += len(self.DecConfig)
+	n += self.fillDescHdr(b[n:], 0x06, datalen-n-self.lenDescHdr())
+	b[n] = 0x02
+	n++
+	pio.PutU32BE(b[0:], uint32(n))
+	return
+}