stbl.go

package mp4

import (
	"encoding/binary"
	"io"
)

// Soample Table Box (stbl - mandatory)
//
// Contained in : Media Information Box (minf)
//
// Status: partially decoded (anything other than stsd, stts, stsc, stss, stsz, stco, ctts is ignored)
//
// The table contains all information relevant to data samples (times, chunks, sizes, ...)
type StblBox struct {
	Stts   *SttsBox
	Stss   *StssBox
	Stsc   *StscBox
	Stsz   *StszBox
	Stco   *StcoBox
	Ctts   *CttsBox
	boxes  []Box
	header [8]byte
}

func DecodeStbl(r io.Reader) (Box, error) {
	l, err := DecodeContainer(r)
	if err != nil {
		return nil, err
	}
	s := &StblBox{
		boxes: make([]Box, 0, len(l)),
	}
	for _, b := range l {
		switch b.Type() {
		case "stts":
			s.Stts = b.(*SttsBox)
		case "stsc":
			s.Stsc = b.(*StscBox)
		case "stss":
			s.Stss = b.(*StssBox)
		case "stsz":
			s.Stsz = b.(*StszBox)
		case "stco":
			s.Stco = b.(*StcoBox)
		case "ctts":
			s.Ctts = b.(*CttsBox)
		default:
			s.boxes = append(s.boxes, b)
		}
	}
	return s, nil
}

func (b *StblBox) Type() string {
	return "stbl"
}

func (b *StblBox) Size() (sz int) {
	if b.Stts != nil {
		sz += b.Stts.Size()
	}
	if b.Stss != nil {
		sz += b.Stss.Size()
	}
	if b.Stsc != nil {
		sz += b.Stsc.Size()
	}
	if b.Stsz != nil {
		sz += b.Stsz.Size()
	}
	if b.Stco != nil {
		sz += b.Stco.Size()
	}
	if b.Ctts != nil {
		sz += b.Ctts.Size()
	}
	for _, box := range b.boxes {
		sz += box.Size()
	}
	return sz + BoxHeaderSize
}

func (b *StblBox) Dump() {
	if b.Stsc != nil {
		b.Stsc.Dump()
	}
	if b.Stts != nil {
		b.Stts.Dump()
	}
	if b.Stss != nil {
		b.Stss.Dump()
	}
	if b.Stco != nil {
		b.Stco.Dump()
	}
}

func (b *StblBox) Encode(w io.Writer) error {
	binary.BigEndian.PutUint32(b.header[:4], uint32(b.Size()))
	copy(b.header[4:], b.Type())
	_, err := w.Write(b.header[:])
	if err != nil {
		return err
	}
	err = b.Stts.Encode(w)
	if err != nil {
		return err
	}
	if b.Stss != nil {
		err = b.Stss.Encode(w)
		if err != nil {
			return err
		}
	}
	err = b.Stsc.Encode(w)
	if err != nil {
		return err
	}
	err = b.Stsz.Encode(w)
	if err != nil {
		return err
	}
	err = b.Stco.Encode(w)
	if err != nil {
		return err
	}
	for _, b := range b.boxes {
		if err = b.Encode(w); err != nil {
			return err
		}
	}
	if b.Ctts != nil {
		return b.Ctts.Encode(w)
	}
	return nil
}