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

64 lines
1.5 KiB
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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 []STTSEntry
func (stts TimeToSampleBox) Size() uint64 {
return FullBoxLen + 4 + 8*uint64(len(stts))
}
func (stts *TimeToSampleBox) Decode(r io.Reader) (offset int, err error) {
var fullbox FullBox
if _, err = fullbox.Decode(r); err != nil {
return
}
entryCountBuf := make([]byte, 4)
if _, err = io.ReadFull(r, entryCountBuf); err != nil {
return
}
offset = 8
l := binary.BigEndian.Uint32(entryCountBuf)
*stts = make([]STTSEntry, l)
buf := make([]byte, l*8)
if _, err = io.ReadFull(r, buf); err != nil {
return
}
idx := 0
for i := 0; i < int(l); i++ {
(*stts)[i].SampleCount = binary.BigEndian.Uint32(buf[idx:])
idx += 4
(*stts)[i].SampleDelta = binary.BigEndian.Uint32(buf[idx:])
idx += 4
}
offset += idx
return
}
func (stts TimeToSampleBox) Encode() (int, []byte) {
fullbox := NewFullBox(TypeSTTS, 0)
fullbox.Box.Size = stts.Size()
offset, buf := fullbox.Encode()
binary.BigEndian.PutUint32(buf[offset:], uint32(len(stts)))
offset += 4
for _, entry := range stts {
binary.BigEndian.PutUint32(buf[offset:], entry.SampleCount)
offset += 4
binary.BigEndian.PutUint32(buf[offset:], entry.SampleDelta)
offset += 4
}
return offset, buf
}