114 lines
2.4 KiB
Go
114 lines
2.4 KiB
Go
package mp4fio
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import (
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"git.r-2.top/kunmeng/vdk/format/mp4/mp4io"
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"git.r-2.top/kunmeng/vdk/utils/bits/pio"
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)
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type ElemStreamDesc struct {
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DecConfig []byte
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TrackId uint16
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mp4io.AtomPos
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}
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func (self ElemStreamDesc) Children() []mp4io.Atom {
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return nil
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}
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func (self ElemStreamDesc) fillLength(b []byte, length int) (n int) {
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b[n] = uint8(length & 0x7f)
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n++
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return
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}
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func (self ElemStreamDesc) lenDescHdr() (n int) {
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return 2
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}
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func (self ElemStreamDesc) fillDescHdr(b []byte, tag uint8, datalen int) (n int) {
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b[n] = tag
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n++
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n += self.fillLength(b[n:], datalen)
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return
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}
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func (self ElemStreamDesc) lenESDescHdr() (n int) {
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return self.lenDescHdr() + 3
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}
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func (self ElemStreamDesc) fillESDescHdr(b []byte, datalen int) (n int) {
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n += self.fillDescHdr(b[n:], mp4io.MP4ESDescrTag, datalen)
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pio.PutU16BE(b[n:], self.TrackId)
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n += 2
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b[n] = 0 // flags
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n++
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return
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}
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func (self ElemStreamDesc) lenDecConfigDescHdr() (n int) {
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return self.lenDescHdr() + 2 + 3 + 4 + 4 + self.lenDescHdr()
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}
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func (self ElemStreamDesc) fillDecConfigDescHdr(b []byte, datalen int) (n int) {
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n += self.fillDescHdr(b[n:], mp4io.MP4DecConfigDescrTag, datalen)
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b[n] = 0x40 // objectid
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n++
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b[n] = 0x15 // streamtype
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n++
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// buffer size db
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pio.PutU24BE(b[n:], 0)
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n += 3
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// max bitrage
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pio.PutU32BE(b[n:], uint32(200000))
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n += 4
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// avg bitrage
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pio.PutU32BE(b[n:], uint32(0))
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n += 4
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n += self.fillDescHdr(b[n:], mp4io.MP4DecSpecificDescrTag, datalen-n)
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return
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}
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func (self ElemStreamDesc) Len() (n int) {
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// len + tag
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return 8 +
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// ver + flags
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4 +
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self.lenESDescHdr() +
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self.lenDecConfigDescHdr() +
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len(self.DecConfig) +
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self.lenDescHdr() + 1
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}
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// Version(4)
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// ESDesc(
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// MP4ESDescrTag
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// ESID(2)
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// ESFlags(1)
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// DecConfigDesc(
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// MP4DecConfigDescrTag
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// objectId streamType bufSize avgBitrate
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// DecSpecificDesc(
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// MP4DecSpecificDescrTag
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// decConfig
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// )
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// )
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// ?Desc(lenDescHdr+1)
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// )
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func (self ElemStreamDesc) Marshal(b []byte) (n int) {
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pio.PutU32BE(b[4:], uint32(mp4io.ESDS))
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n += 8
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pio.PutU32BE(b[n:], 0) // Version
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n += 4
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datalen := self.Len()
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n += self.fillESDescHdr(b[n:], datalen-n-self.lenESDescHdr()+3)
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n += self.fillDecConfigDescHdr(b[n:], datalen-n-self.lenDescHdr()-3)
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copy(b[n:], self.DecConfig)
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n += len(self.DecConfig)
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n += self.fillDescHdr(b[n:], 0x06, datalen-n-self.lenDescHdr())
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b[n] = 0x02
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n++
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pio.PutU32BE(b[0:], uint32(n))
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return
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}
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