Total rework FLV client

pkg/flv/flv.go

@@ -0,0 +1,62 @@
+package flv
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+const (
+	TagAudio = 8
+	TagVideo = 9
+	TagData  = 18
+
+	CodecAAC = 10
+	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
+}
+
+func (c *Client) 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 {
+		return 0, 0, nil, err
+	}
+
+	b = b[4 : 4+11] // skip previous tag size
+
+	tagType := b[0]
+	size := uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3])
+	timeMS := uint32(b[4])<<16 | uint32(b[5])<<8 | uint32(b[6]) | uint32(b[7])<<24
+
+	b = make([]byte, size)
+	if _, err := io.ReadFull(c.rd, b); err != nil {
+		return 0, 0, nil, err
+	}
+
+	return tagType, timeMS, b, nil
+}
+
+func TimeToRTP(timeMS uint32, clockRate uint32) uint32 {
+	return timeMS * clockRate / 1000
+}