Files
monibuca/plugin/mp4/pkg/box/edts.go
2024-09-12 18:23:36 +08:00

106 lines
2.7 KiB
Go
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
package box
import (
"encoding/binary"
"io"
)
// aligned(8) class EditListBox extends FullBox(elst, version, 0) {
// unsigned int(32) entry_count;
// for (i=1; i <= entry_count; i++) {
// if (version==1) {
// unsigned int(64) segment_duration;
// int(64) media_time;
// } else { // version==0
// unsigned int(32) segment_duration;
// int(32) media_time;
// }
// int(16) media_rate_integer;
// int(16) media_rate_fraction = 0;
// }
// }
type EditListBox struct {
Version byte
Entrys []ELSTEntry
}
func NewEditListBox(version byte) *EditListBox {
return &EditListBox{
Version: version,
}
}
func (elst *EditListBox) Encode(boxSize int) (int, []byte) {
fullbox := NewFullBox(TypeELST, elst.Version)
fullbox.Box.Size = uint64(boxSize)
offset, elstdata := fullbox.Encode()
binary.BigEndian.PutUint32(elstdata[offset:], uint32(len(elst.Entrys)))
offset += 4
for _, entry := range elst.Entrys {
if elst.Version == 1 {
binary.BigEndian.PutUint64(elstdata[offset:], entry.SegmentDuration)
offset += 8
binary.BigEndian.PutUint64(elstdata[offset:], uint64(entry.MediaTime))
offset += 8
} else {
binary.BigEndian.PutUint32(elstdata[offset:], uint32(entry.SegmentDuration))
offset += 4
binary.BigEndian.PutUint32(elstdata[offset:], uint32(entry.MediaTime))
offset += 4
}
binary.BigEndian.PutUint16(elstdata[offset:], uint16(entry.MediaRateInteger))
offset += 2
binary.BigEndian.PutUint16(elstdata[offset:], uint16(entry.MediaRateFraction))
offset += 2
}
return offset, elstdata
}
func (elst *EditListBox) Decode(r io.Reader) (offset int, err error) {
var fullbox FullBox
if offset, err = fullbox.Decode(r); err != nil {
return 0, err
}
entryCountBuf := make([]byte, 4)
if _, err = io.ReadFull(r, entryCountBuf); err != nil {
return
}
entryCount := binary.BigEndian.Uint32(entryCountBuf)
offset += 4
var boxsize uint32
if elst.Version == 0 {
boxsize = 12 * entryCount
} else {
boxsize = 20 * entryCount
}
buf := make([]byte, boxsize)
if _, err := io.ReadFull(r, buf); err != nil {
return 0, err
}
if elst.Entrys == nil {
elst.Entrys = make([]ELSTEntry, entryCount)
}
nn := 0
for i := range entryCount {
entry := &elst.Entrys[i]
if elst.Version == 0 {
entry.SegmentDuration = uint64(binary.BigEndian.Uint32(buf[nn:]))
nn += 4
entry.MediaTime = int64(int32(binary.BigEndian.Uint32(buf[nn:])))
nn += 4
} else {
entry.SegmentDuration = uint64(binary.BigEndian.Uint64(buf[nn:]))
nn += 8
entry.MediaTime = int64(binary.BigEndian.Uint64(buf[nn:]))
nn += 8
}
entry.MediaRateInteger = int16(binary.BigEndian.Uint16(buf[nn:]))
nn += 2
entry.MediaRateFraction = int16(binary.BigEndian.Uint16(buf[nn:]))
nn += 2
}
return offset + nn, nil
}