Add SPS parser and AVC/HVC conf encoders

pkg/bits/reader.go

@@ -1,10 +1,12 @@
 package bits
 
 type Reader struct {
-	buf  []byte // packets buffer
-	byte byte
-	bits byte
-	pos  int
+	EOF bool // if end of buffer raised during reading
+
+	buf  []byte // total buf
+	byte byte   // current byte
+	bits byte   // bits left in byte
+	pos  int    // current pos in buf
 }
 
 func NewReader(b []byte) *Reader {
@@ -14,6 +16,11 @@ func NewReader(b []byte) *Reader {
 //goland:noinspection GoStandardMethods
 func (r *Reader) ReadByte() byte {
 	if r.bits == 0 {
+		if r.pos >= len(r.buf) {
+			r.EOF = true
+			return 0
+		}
+
 		b := r.buf[r.pos]
 		r.pos++
 		return b
@@ -54,14 +61,20 @@ func (r *Reader) ReadBits16(n byte) (res uint16) {
 	return
 }
 
-func (r *Reader) SkipBits(n int) {
-	for i := 0; i < n; i++ {
-		if r.bits == 0 {
-			r.byte = r.buf[r.pos]
-			r.pos++
-			r.bits = 7
-		} else {
-			r.bits--
+func (r *Reader) ReadUEGolomb() uint32 {
+	var size byte
+	for size = 0; size < 32; size++ {
+		if b := r.ReadBit(); b != 0 || r.EOF {
+			break
 		}
 	}
+	return r.ReadBits(size) + (1 << size) - 1
+}
+
+func (r *Reader) ReadSEGolomb() int32 {
+	if b := r.ReadUEGolomb(); b%2 == 0 {
+		return -int32(b >> 1)
+	} else {
+		return int32(b >> 1)
+	}
 }