Create AnnexB2AVC func

pkg/h264/avc.go

@@ -1,11 +1,31 @@
 package h264
 
 import (
+	"bytes"
 	"encoding/binary"
 	"github.com/AlexxIT/go2rtc/pkg/streamer"
 	"github.com/pion/rtp"
 )
 
+func AnnexB2AVC(b []byte) []byte {
+	for i := 0; i < len(b); {
+		if i+4 >= len(b) {
+			break
+		}
+
+		size := bytes.Index(b[i+4:], []byte{0, 0, 0, 1})
+		if size < 0 {
+			size = len(b) - (i + 4)
+		}
+
+		binary.BigEndian.PutUint32(b[i:], uint32(size))
+
+		i += size + 4
+	}
+
+	return b
+}
+
 func EncodeAVC(nals ...[]byte) (avc []byte) {
 	var i, n int