Rewrite support MPEG-TS client
This commit is contained in:
Alexey Khit
+268
-165
@@ -1,209 +1,312 @@
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package mpegts
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import "github.com/pion/rtp"
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import (
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"errors"
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"io"
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"github.com/pion/rtp"
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)
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type Reader struct {
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b []byte // packets buffer
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i byte // read position
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s byte // end position
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buf [PacketSize]byte // total buf
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pmt uint16 // Program Map Table (PMT) PID
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pes map[uint16]*PES
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byte byte // current byte
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bits byte // bits left in byte
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pos byte // current pos in buf
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end byte // end position
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pmtID uint16 // Program Map Table (PMT) PID
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pes map[uint16]*PES
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}
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func NewReader() *Reader {
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return &Reader{}
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}
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func (r *Reader) SetBuffer(b []byte) {
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r.b = b
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r.i = 0
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r.s = PacketSize
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}
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const skipRead = 0xFF
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func (r *Reader) AppendBuffer(b []byte) {
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r.b = append(r.b, b...)
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}
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func (r *Reader) GetPacket() *rtp.Packet {
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for r.Sync() {
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r.Skip(1) // Sync byte
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pid := r.ReadUint16() & 0x1FFF // PID
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flag := r.ReadByte() // flags...
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const pidNullPacket = 0x1FFF
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if pid == pidNullPacket {
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continue
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func (r *Reader) ReadPacket(rd io.Reader) (*rtp.Packet, error) {
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for {
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if r.pos != skipRead {
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if _, err := io.ReadFull(rd, r.buf[:]); err != nil {
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return nil, err
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}
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}
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const hasAdaptionField = 0b0010_0000
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if flag&hasAdaptionField != 0 {
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adSize := r.ReadByte() // Adaptation field length
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if adSize > PacketSize-6 {
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println("WARNING: mpegts: wrong adaptation size")
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continue
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}
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r.Skip(adSize)
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}
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// PAT: Program Association Table
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const pidPAT = 0
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if pid == pidPAT {
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// already processed
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if r.pmt != 0 {
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continue
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}
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r.ReadPSIHeader()
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const CRCSize = 4
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for r.Left() > CRCSize {
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pNum := r.ReadUint16()
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pPID := r.ReadUint16() & 0x1FFF
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if pNum != 0 {
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r.pmt = pPID
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}
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}
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r.Skip(4) // CRC32
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continue
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}
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// PMT : Program Map Table
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if pid == r.pmt {
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// already processed
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if r.pes != nil {
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continue
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}
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r.ReadPSIHeader()
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pesPID := r.ReadUint16() & 0x1FFF // ? PCR PID
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pSize := r.ReadUint16() & 0x03FF // ? 0x0FFF
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r.Skip(byte(pSize))
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r.pes = map[uint16]*PES{}
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const CRCSize = 4
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for r.Left() > CRCSize {
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streamType := r.ReadByte()
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pesPID = r.ReadUint16() & 0x1FFF // Elementary PID
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iSize := r.ReadUint16() & 0x03FF // ? 0x0FFF
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r.Skip(byte(iSize))
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r.pes[pesPID] = &PES{StreamType: streamType}
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}
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r.Skip(4) // ? CRC32
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continue
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pid, start, err := r.readPacketHeader()
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if err != nil {
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return nil, err
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}
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if r.pes == nil {
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switch pid {
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case 0: // PAT ID
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r.readPAT() // PAT: Program Association Table
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case r.pmtID:
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r.readPMT() // PMT : Program Map Table
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pkt := &rtp.Packet{
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Payload: make([]byte, 0, len(r.pes)),
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}
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for _, pes := range r.pes {
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pkt.Payload = append(pkt.Payload, pes.StreamType)
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}
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return pkt, nil
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}
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continue
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}
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pes := r.pes[pid]
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if pes == nil {
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continue // unknown PID
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if pkt := r.readPES(pid, start); pkt != nil {
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return pkt, nil
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}
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}
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}
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func (r *Reader) readPacketHeader() (pid uint16, start bool, err error) {
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r.reset()
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sb := r.readByte() // Sync byte
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if sb != SyncByte {
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return 0, false, errors.New("mpegts: wrong sync byte")
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}
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_ = r.readBit() // Transport error indicator (TEI)
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pusi := r.readBit() // Payload unit start indicator (PUSI)
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_ = r.readBit() // Transport priority
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pid = r.readBits16(13) // PID
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_ = r.readBits(2) // Transport scrambling control (TSC)
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af := r.readBit() // Adaptation field
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_ = r.readBit() // Payload
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_ = r.readBits(4) // Continuity counter
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if af != 0 {
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adSize := r.readByte() // Adaptation field length
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if adSize > PacketSize-6 {
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return 0, false, errors.New("mpegts: wrong adaptation size")
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}
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r.skip(adSize)
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}
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return pid, pusi != 0, nil
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}
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func (r *Reader) skip(i byte) {
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r.pos += i
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}
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func (r *Reader) readPSIHeader() {
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// https://en.wikipedia.org/wiki/Program-specific_information#Table_Sections
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pointer := r.readByte() // Pointer field
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r.skip(pointer) // Pointer filler bytes
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_ = r.readByte() // Table ID
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_ = r.readBit() // Section syntax indicator
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_ = r.readBit() // Private bit
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_ = r.readBits(2) // Reserved bits
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_ = r.readBits(2) // Section length unused bits
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size := r.readBits(10) // Section length
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r.setSize(byte(size))
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_ = r.readBits(16) // Table ID extension
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_ = r.readBits(2) // Reserved bits
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_ = r.readBits(5) // Version number
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_ = r.readBit() // Current/next indicator
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_ = r.readByte() // Section number
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_ = r.readByte() // Last section number
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}
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// ReadPAT (Program Association Table)
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func (r *Reader) readPAT() {
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// https://en.wikipedia.org/wiki/Program-specific_information#PAT_(Program_Association_Table)
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r.readPSIHeader()
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const CRCSize = 4
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for r.left() > CRCSize {
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num := r.readBits(16) // Program num
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_ = r.readBits(3) // Reserved bits
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pid := r.readBits16(13) // Program map PID
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if num != 0 {
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r.pmtID = pid
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}
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}
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r.skip(4) // CRC32
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}
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// ReadPMT (Program map specific data)
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func (r *Reader) readPMT() {
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// https://en.wikipedia.org/wiki/Program-specific_information#PMT_(Program_map_specific_data)
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r.readPSIHeader()
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_ = r.readBits(3) // Reserved bits
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_ = r.readBits(13) // PCR PID
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_ = r.readBits(4) // Reserved bits
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_ = r.readBits(2) // Program info length unused bits
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size := r.readBits(10) // Program info length
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r.skip(byte(size))
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r.pes = map[uint16]*PES{}
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const CRCSize = 4
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for r.left() > CRCSize {
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streamType := r.readByte() // Stream type
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_ = r.readBits(3) // Reserved bits
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pid := r.readBits16(13) // Elementary PID
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_ = r.readBits(4) // Reserved bits
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_ = r.readBits(2) // ES Info length unused bits
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size = r.readBits(10) // ES Info length
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r.skip(byte(size))
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r.pes[pid] = &PES{StreamType: streamType}
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}
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r.skip(4) // CRC32
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}
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func (r *Reader) readPES(pid uint16, start bool) *rtp.Packet {
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pes := r.pes[pid]
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if pes == nil {
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return nil
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}
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// if new payload beging
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if start {
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if pes.Payload != nil {
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r.pos = skipRead
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return pes.GetPacket() // finish previous packet
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}
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if pes.Payload == nil {
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// PES Packet start code prefix
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if r.ReadByte() != 0 || r.ReadByte() != 0 || r.ReadByte() != 1 {
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continue
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}
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// read stream ID and total payload size
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pes.StreamID = r.ReadByte()
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pes.SetBuffer(r.ReadUint16(), r.Bytes())
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} else {
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pes.AppendBuffer(r.Bytes())
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// https://en.wikipedia.org/wiki/Packetized_elementary_stream
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// Packet start code prefix
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if r.readByte() != 0 || r.readByte() != 0 || r.readByte() != 1 {
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return nil
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}
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if pkt := pes.GetPacket(); pkt != nil {
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return pkt
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pes.StreamID = r.readByte() // Stream id
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packetSize := r.readBits16(16) // PES Packet length
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_ = r.readBits(2) // Marker bits
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_ = r.readBits(2) // Scrambling control
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_ = r.readBit() // Priority
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_ = r.readBit() // Data alignment indicator
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_ = r.readBit() // Copyright
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_ = r.readBit() // Original or Copy
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pts := r.readBit() // PTS indicator
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_ = r.readBit() // DTS indicator
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_ = r.readBit() // ESCR flag
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_ = r.readBit() // ES rate flag
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_ = r.readBit() // DSM trick mode flag
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_ = r.readBit() // Additional copy info flag
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_ = r.readBit() // CRC flag
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_ = r.readBit() // extension flag
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headerSize := r.readByte() // PES header length
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//log.Printf("[mpegts] pes=%d size=%d header=%d", pes.StreamID, packetSize, headerSize)
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if packetSize != 0 {
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packetSize -= uint16(3 + headerSize)
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}
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if pts != 0 {
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pes.PTS = r.readTime()
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headerSize -= 5
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}
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r.skip(headerSize)
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pes.SetBuffer(packetSize, r.bytes())
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} else {
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pes.AppendBuffer(r.bytes())
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}
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if pes.Size != 0 && len(pes.Payload) >= pes.Size {
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return pes.GetPacket() // finish current packet
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}
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return nil
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}
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func (r *Reader) GetStreamTypes() []byte {
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types := make([]byte, 0, len(r.pes))
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for _, pes := range r.pes {
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types = append(types, pes.StreamType)
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}
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return types
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func (r *Reader) reset() {
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r.pos = 0
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r.end = PacketSize
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r.bits = 0
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}
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// Sync - search sync byte
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func (r *Reader) Sync() bool {
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// drop previous readed packet
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if r.i != 0 {
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r.b = r.b[PacketSize:]
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r.i = 0
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r.s = PacketSize
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//goland:noinspection GoStandardMethods
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func (r *Reader) readByte() byte {
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if r.bits != 0 {
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return byte(r.readBits(8))
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}
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// if packet available
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if len(r.b) < PacketSize {
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return false
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}
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// if data starts from sync byte
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if r.b[0] == SyncByte {
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return true
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}
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for len(r.b) >= PacketSize {
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if r.b[0] == SyncByte {
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return true
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}
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r.b = r.b[1:]
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}
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return false
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}
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func (r *Reader) ReadPSIHeader() {
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pointer := r.ReadByte() // Pointer field
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r.Skip(pointer) // Pointer filler bytes
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r.Skip(1) // Table ID
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size := r.ReadUint16() & 0x03FF // Section length
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r.SetSize(byte(size))
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r.Skip(2) // Table ID extension
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r.Skip(1) // flags...
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r.Skip(1) // Section number
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r.Skip(1) // Last section number
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}
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func (r *Reader) Skip(i byte) {
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r.i += i
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}
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func (r *Reader) ReadByte() byte {
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b := r.b[r.i]
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r.i++
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b := r.buf[r.pos]
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r.pos++
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return b
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}
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func (r *Reader) ReadUint16() uint16 {
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i := (uint16(r.b[r.i]) << 8) | uint16(r.b[r.i+1])
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r.i += 2
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return i
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func (r *Reader) readBit() byte {
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if r.bits == 0 {
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r.byte = r.readByte()
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r.bits = 7
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} else {
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r.bits--
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}
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return (r.byte >> r.bits) & 0b1
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}
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func (r *Reader) Bytes() []byte {
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return r.b[r.i:PacketSize]
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func (r *Reader) readBits(n byte) (res uint32) {
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for i := n - 1; i != 255; i-- {
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res |= uint32(r.readBit()) << i
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}
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return
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}
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func (r *Reader) Left() byte {
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return r.s - r.i
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func (r *Reader) readBits16(n byte) (res uint16) {
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for i := n - 1; i != 255; i-- {
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res |= uint16(r.readBit()) << i
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}
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return
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}
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func (r *Reader) SetSize(size byte) {
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r.s = r.i + size
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func (r *Reader) readTime() uint32 {
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// https://en.wikipedia.org/wiki/Packetized_elementary_stream
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// xxxxAAAx BBBBBBBB BBBBBBBx CCCCCCCC CCCCCCCx
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_ = r.readBits(4) // 0010b or 0011b or 0001b
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ts := r.readBits(3) << 30
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_ = r.readBits(1) // 1b
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ts |= r.readBits(15) << 15
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_ = r.readBits(1) // 1b
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ts |= r.readBits(15)
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_ = r.readBits(1) // 1b
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return ts
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}
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func (r *Reader) bytes() []byte {
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return r.buf[r.pos:PacketSize]
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}
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func (r *Reader) left() byte {
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return r.end - r.pos
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}
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func (r *Reader) setSize(size byte) {
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r.end = r.pos + size
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}
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// Deprecated:
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func (r *Reader) SetBuffer(b []byte) {
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}
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// Deprecated:
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func (r *Reader) GetPacket() *rtp.Packet {
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panic("")
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}
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// Deprecated:
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func (r *Reader) AppendBuffer(sniff []byte) {
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}
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