Files
monibuca/plugin/mp4/pkg/box/stsz.go
2024-10-06 17:56:11 +08:00

76 lines
1.7 KiB
Go
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package box
import (
"encoding/binary"
"io"
)
// aligned(8) class SampleSizeBox extends FullBox(stsz, version = 0, 0) {
// unsigned int(32) sample_size;
// unsigned int(32) sample_count;
// if (sample_size==0) {
// for (i=1; i <= sample_count; i++) {
// unsigned int(32) entry_size;
// }
// }
// }
type SampleSizeBox struct {
SampleSize uint32
SampleCount uint32
EntrySizelist []uint32
}
func (stsz *SampleSizeBox) Size() uint64 {
if stsz.SampleSize == 0 {
return FullBoxLen + 8 + 4*uint64(stsz.SampleCount)
} else {
return FullBoxLen + 8
}
}
func (stsz *SampleSizeBox) Decode(r io.Reader) (offset int, err error) {
var fullbox FullBox
if _, err = fullbox.Decode(r); err != nil {
return
}
tmp := make([]byte, 8)
if _, err = io.ReadFull(r, tmp); err != nil {
return
}
offset = 12
stsz.SampleSize = binary.BigEndian.Uint32(tmp[:])
stsz.SampleCount = binary.BigEndian.Uint32(tmp[4:])
if stsz.SampleSize == 0 {
buf := make([]byte, stsz.SampleCount*4)
if _, err = io.ReadFull(r, buf); err != nil {
return
}
idx := 0
stsz.EntrySizelist = make([]uint32, stsz.SampleCount)
for i := 0; i < int(stsz.SampleCount); i++ {
stsz.EntrySizelist[i] = binary.BigEndian.Uint32(buf[idx:])
idx += 4
}
offset += idx
}
return
}
func (stsz *SampleSizeBox) Encode() (int, []byte) {
fullbox := NewFullBox(TypeSTSZ, 0)
fullbox.Box.Size = stsz.Size()
offset, buf := fullbox.Encode()
binary.BigEndian.PutUint32(buf[offset:], stsz.SampleSize)
offset += 4
binary.BigEndian.PutUint32(buf[offset:], stsz.SampleCount)
offset += 4
if stsz.SampleSize == 0 {
for i := 0; i < int(stsz.SampleCount); i++ {
binary.BigEndian.PutUint32(buf[offset:], stsz.EntrySizelist[i])
offset += 4
}
}
return offset, buf
}