Files
monibuca/plugin/mp4/pkg/box/stts-box.go
2024-07-19 14:06:46 +08:00

93 lines
2.3 KiB
Go
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package box
import (
"encoding/binary"
"io"
)
// aligned(8) class TimeToSampleBox extends FullBox(stts, version = 0, 0) {
// unsigned int(32) entry_count;
// int i;
// for (i=0; i < entry_count; i++) {
// unsigned int(32) sample_count;
// unsigned int(32) sample_delta;
// }
// }
type TimeToSampleBox struct {
box *FullBox
entryList *movstts
}
func NewTimeToSampleBox() *TimeToSampleBox {
return &TimeToSampleBox{
box: NewFullBox([4]byte{'s', 't', 't', 's'}, 0),
}
}
func (stts *TimeToSampleBox) Size() uint64 {
if stts.entryList == nil {
return stts.box.Size()
} else {
return stts.box.Size() + 4 + 8*uint64(stts.entryList.entryCount)
}
}
func (stts *TimeToSampleBox) Decode(r io.Reader) (offset int, err error) {
if _, err = stts.box.Decode(r); err != nil {
return
}
entryCountBuf := make([]byte, 4)
if _, err = io.ReadFull(r, entryCountBuf); err != nil {
return
}
offset = 8
stts.entryList = new(movstts)
stts.entryList.entryCount = binary.BigEndian.Uint32(entryCountBuf)
stts.entryList.entrys = make([]sttsEntry, stts.entryList.entryCount)
buf := make([]byte, stts.entryList.entryCount*8)
if _, err = io.ReadFull(r, buf); err != nil {
return
}
idx := 0
for i := 0; i < int(stts.entryList.entryCount); i++ {
stts.entryList.entrys[i].sampleCount = binary.BigEndian.Uint32(buf[idx:])
idx += 4
stts.entryList.entrys[i].sampleDelta = binary.BigEndian.Uint32(buf[idx:])
idx += 4
}
offset += idx
return
}
func (stts *TimeToSampleBox) Encode() (int, []byte) {
stts.box.Box.Size = stts.Size()
offset, buf := stts.box.Encode()
binary.BigEndian.PutUint32(buf[offset:], stts.entryList.entryCount)
offset += 4
for i := 0; i < int(stts.entryList.entryCount); i++ {
binary.BigEndian.PutUint32(buf[offset:], stts.entryList.entrys[i].sampleCount)
offset += 4
binary.BigEndian.PutUint32(buf[offset:], stts.entryList.entrys[i].sampleDelta)
offset += 4
}
return offset, buf
}
func makeStts(stts *movstts) (boxdata []byte) {
sttsbox := NewTimeToSampleBox()
sttsbox.entryList = stts
_, boxdata = sttsbox.Encode()
return
}
func decodeSttsBox(demuxer *MovDemuxer) (err error) {
stts := TimeToSampleBox{box: new(FullBox)}
if _, err = stts.Decode(demuxer.reader); err != nil {
return
}
track := demuxer.tracks[len(demuxer.tracks)-1]
track.stbltable.stts = stts.entryList
return
}