Total rework RTMP client

pkg/flv/flv.go

@@ -15,28 +15,25 @@ const (
 	CodecAVC = 7
 )
 
-func (c *Client) ReadHeader() error {
-	b := make([]byte, 9)
-	if _, err := io.ReadFull(c.rd, b); err != nil {
-		return err
-	}
-
-	if string(b[:3]) != "FLV" {
-		return errors.New("flv: wrong header")
-	}
-
-	_ = b[4] // flags (skip because unsupported by Reolink cameras)
-
-	if skip := binary.BigEndian.Uint32(b[5:]) - 9; skip > 0 {
-		if _, err := io.ReadFull(c.rd, make([]byte, skip)); err != nil {
-			return err
-		}
-	}
-
-	return nil
+// Transport - it is recommended to implement io.Closer
+type Transport interface {
+	ReadTag() (byte, uint32, []byte, error)
 }
 
-func (c *Client) ReadTag() (byte, uint32, []byte, error) {
+// NewTransport - it is recommended to use bufio.Reader
+func NewTransport(rd io.Reader) (Transport, error) {
+	c := &flv{rd: rd}
+	if err := c.readHeader(); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+type flv struct {
+	rd io.Reader
+}
+
+func (c *flv) ReadTag() (byte, uint32, []byte, error) {
 	// https://rtmp.veriskope.com/pdf/video_file_format_spec_v10.pdf
 	b := make([]byte, 4+11)
 	if _, err := io.ReadFull(c.rd, b); err != nil {
@@ -57,6 +54,34 @@ func (c *Client) ReadTag() (byte, uint32, []byte, error) {
 	return tagType, timeMS, b, nil
 }
 
+func (c *flv) Close() error {
+	if closer, ok := c.rd.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}
+
+func (c *flv) readHeader() error {
+	b := make([]byte, 9)
+	if _, err := io.ReadFull(c.rd, b); err != nil {
+		return err
+	}
+
+	if string(b[:3]) != "FLV" {
+		return errors.New("flv: wrong header")
+	}
+
+	_ = b[4] // flags (skip because unsupported by Reolink cameras)
+
+	if skip := binary.BigEndian.Uint32(b[5:]) - 9; skip > 0 {
+		if _, err := io.ReadFull(c.rd, make([]byte, skip)); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func TimeToRTP(timeMS uint32, clockRate uint32) uint32 {
 	return timeMS * clockRate / 1000
 }