Alexey Khit
88 lines
1.7 KiB
Go
88 lines
1.7 KiB
Go
package flv
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import (
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"encoding/binary"
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"errors"
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"io"
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)
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const (
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TagAudio = 8
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TagVideo = 9
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TagData = 18
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CodecAAC = 10
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CodecAVC = 7
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)
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// Transport - it is recommended to implement io.Closer
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type Transport interface {
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ReadTag() (byte, uint32, []byte, error)
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}
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// NewTransport - it is recommended to use bufio.Reader
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func NewTransport(rd io.Reader) (Transport, error) {
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c := &flv{rd: rd}
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if err := c.readHeader(); err != nil {
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return nil, err
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}
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return c, nil
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}
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type flv struct {
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rd io.Reader
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}
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func (c *flv) ReadTag() (byte, uint32, []byte, error) {
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// https://rtmp.veriskope.com/pdf/video_file_format_spec_v10.pdf
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b := make([]byte, 4+11)
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if _, err := io.ReadFull(c.rd, b); err != nil {
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return 0, 0, nil, err
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}
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b = b[4 : 4+11] // skip previous tag size
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tagType := b[0]
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size := uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3])
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timeMS := uint32(b[4])<<16 | uint32(b[5])<<8 | uint32(b[6]) | uint32(b[7])<<24
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b = make([]byte, size)
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if _, err := io.ReadFull(c.rd, b); err != nil {
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return 0, 0, nil, err
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}
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return tagType, timeMS, b, nil
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}
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func (c *flv) Close() error {
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if closer, ok := c.rd.(io.Closer); ok {
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return closer.Close()
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}
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return nil
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}
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func (c *flv) readHeader() error {
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b := make([]byte, 9)
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if _, err := io.ReadFull(c.rd, b); err != nil {
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return err
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}
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if string(b[:3]) != "FLV" {
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return errors.New("flv: wrong header")
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}
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_ = b[4] // flags (skip because unsupported by Reolink cameras)
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if skip := binary.BigEndian.Uint32(b[5:]) - 9; skip > 0 {
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if _, err := io.ReadFull(c.rd, make([]byte, skip)); err != nil {
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return err
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}
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}
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return nil
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}
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func TimeToRTP(timeMS uint32, clockRate uint32) uint32 {
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return timeMS * clockRate / 1000
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}
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