Add support B-frames for MP4 consumer

pkg/iso/atoms.go

@@ -276,7 +276,7 @@ const (
 	TrunSampleCTS        = 0x0000800
 )
 
-func (m *Movie) WriteMovieFragment(seq, tid, duration, size, flags uint32, time uint64) {
+func (m *Movie) WriteMovieFragment(seq, tid, duration, size, flags uint32, dts uint64, cts uint32) {
 	m.StartAtom(Moof)
 
 	m.StartAtom(MoofMfhd)
@@ -302,17 +302,29 @@ func (m *Movie) WriteMovieFragment(seq, tid, duration, size, flags uint32, time
 	m.EndAtom()
 
 	m.StartAtom(MoofTrafTfdt)
-	m.WriteBytes(1)     // version
-	m.Skip(3)           // flags
-	m.WriteUint64(time) // base media decode time
+	m.WriteBytes(1)    // version
+	m.Skip(3)          // flags
+	m.WriteUint64(dts) // base media decode time
 	m.EndAtom()
 
 	m.StartAtom(MoofTrafTrun)
-	m.Skip(1)                     // version
-	m.WriteUint24(TrunDataOffset) // flags
-	m.WriteUint32(1)              // sample count
-	// data offset: current pos + uint32 len + MDAT header len
-	m.WriteUint32(uint32(len(m.b)) + 4 + 8)
+	m.Skip(1) // version
+
+	if cts == 0 {
+		m.WriteUint24(TrunDataOffset) // flags
+		m.WriteUint32(1)              // sample count
+
+		// data offset: current pos + uint32 len + MDAT header len
+		m.WriteUint32(uint32(len(m.b)) + 4 + 8)
+	} else {
+		m.WriteUint24(TrunDataOffset | TrunSampleCTS)
+		m.WriteUint32(1)
+
+		// data offset: current pos + uint32 len + CTS + MDAT header len
+		m.WriteUint32(uint32(len(m.b)) + 4 + 4 + 8)
+		m.WriteUint32(cts)
+	}
+
 	m.EndAtom() // TRUN
 
 	m.EndAtom() // TRAF