/
demuxer.go
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/
demuxer.go
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package ts
import (
"bufio"
"fmt"
"io"
"time"
"github.com/Youngju-Heo/gomedia/core/media/av"
"github.com/Youngju-Heo/gomedia/core/media/codec/aacparser"
"github.com/Youngju-Heo/gomedia/core/media/codec/h264parser"
"github.com/Youngju-Heo/gomedia/core/media/format/ts/tsio"
"github.com/Youngju-Heo/gomedia/core/media/utils/bits/pio"
)
// Demuxer type
type Demuxer struct {
r *bufio.Reader
pkts []av.Packet
pat *tsio.PAT
pmt *tsio.PMT
streams []*Stream
tshdr []byte
stage int
}
// NewDemuxer func
func NewDemuxer(r io.Reader) *Demuxer {
return &Demuxer{
tshdr: make([]byte, 188),
r: bufio.NewReaderSize(r, pio.RecommendBufioSize),
}
}
// Streams func
func (demuxer *Demuxer) Streams() (streams []av.CodecData, err error) {
if err = demuxer.probe(); err != nil {
return
}
for _, stream := range demuxer.streams {
streams = append(streams, stream.CodecData)
}
return
}
func (demuxer *Demuxer) probe() (err error) {
if demuxer.stage == 0 {
for {
if demuxer.pmt != nil {
n := 0
for _, stream := range demuxer.streams {
if stream.CodecData != nil {
n++
}
}
if n == len(demuxer.streams) {
break
}
}
if err = demuxer.poll(); err != nil {
return
}
}
demuxer.stage++
}
return
}
// ReadPacket func
func (demuxer *Demuxer) ReadPacket() (pkt av.Packet, err error) {
if err = demuxer.probe(); err != nil {
return
}
for len(demuxer.pkts) == 0 {
if err = demuxer.poll(); err != nil {
return
}
}
pkt = demuxer.pkts[0]
demuxer.pkts = demuxer.pkts[1:]
return
}
func (demuxer *Demuxer) poll() (err error) {
if err = demuxer.readTSPacket(); err == io.EOF {
var n int
if n, err = demuxer.payloadEnd(); err != nil {
return
}
if n == 0 {
err = io.EOF
}
}
return
}
func (demuxer *Demuxer) initPMT(payload []byte) (err error) {
var psihdrlen int
var datalen int
if _, _, psihdrlen, datalen, err = tsio.ParsePSI(payload); err != nil {
return
}
demuxer.pmt = &tsio.PMT{}
if _, err = demuxer.pmt.Unmarshal(payload[psihdrlen : psihdrlen+datalen]); err != nil {
return
}
demuxer.streams = []*Stream{}
for i, info := range demuxer.pmt.ElementaryStreamInfos {
stream := &Stream{}
stream.idx = i
stream.demuxer = demuxer
stream.pid = info.ElementaryPID
stream.streamType = info.StreamType
switch info.StreamType {
case tsio.ElementaryStreamTypeH264:
demuxer.streams = append(demuxer.streams, stream)
case tsio.ElementaryStreamTypeAdtsAAC:
demuxer.streams = append(demuxer.streams, stream)
}
}
return
}
func (demuxer *Demuxer) payloadEnd() (n int, err error) {
for _, stream := range demuxer.streams {
var i int
if i, err = stream.payloadEnd(); err != nil {
return
}
n += i
}
return
}
func (demuxer *Demuxer) readTSPacket() (err error) {
var hdrlen int
var pid uint16
var start bool
var iskeyframe bool
if _, err = io.ReadFull(demuxer.r, demuxer.tshdr); err != nil {
return
}
if pid, start, iskeyframe, hdrlen, err = tsio.ParseTSHeader(demuxer.tshdr); err != nil {
return
}
payload := demuxer.tshdr[hdrlen:]
if demuxer.pat == nil {
if pid == 0 {
var psihdrlen int
var datalen int
if _, _, psihdrlen, datalen, err = tsio.ParsePSI(payload); err != nil {
return
}
demuxer.pat = &tsio.PAT{}
if _, err = demuxer.pat.Unmarshal(payload[psihdrlen : psihdrlen+datalen]); err != nil {
return
}
}
} else if demuxer.pmt == nil {
for _, entry := range demuxer.pat.Entries {
if entry.ProgramMapPID == pid {
if err = demuxer.initPMT(payload); err != nil {
return
}
break
}
}
} else {
for _, stream := range demuxer.streams {
if pid == stream.pid {
if err = stream.handleTSPacket(start, iskeyframe, payload); err != nil {
return
}
break
}
}
}
return
}
func (stream *Stream) addPacket(payload []byte, timedelta time.Duration) {
dts := stream.dts
pts := stream.pts
if dts == 0 {
dts = pts
}
demuxer := stream.demuxer
pkt := av.Packet{
Idx: int8(stream.idx),
IsKeyFrame: stream.iskeyframe,
Time: dts + timedelta,
Data: payload,
}
if pts != dts {
pkt.CompositionTime = pts - dts
}
demuxer.pkts = append(demuxer.pkts, pkt)
}
func (stream *Stream) payloadEnd() (n int, err error) {
payload := stream.data
if payload == nil {
return
}
if stream.datalen != 0 && len(payload) != stream.datalen {
err = fmt.Errorf("ts: packet size mismatch size=%d correct=%d", len(payload), stream.datalen)
return
}
stream.data = nil
switch stream.streamType {
case tsio.ElementaryStreamTypeAdtsAAC:
var config aacparser.MPEG4AudioConfig
delta := time.Duration(0)
for len(payload) > 0 {
var hdrlen, framelen, samples int
if config, hdrlen, framelen, samples, err = aacparser.ParseADTSHeader(payload); err != nil {
return
}
if stream.CodecData == nil {
if stream.CodecData, err = aacparser.NewCodecDataFromMPEG4AudioConfig(config); err != nil {
return
}
}
stream.addPacket(payload[hdrlen:framelen], delta)
n++
delta += time.Duration(samples) * time.Second / time.Duration(config.SampleRate)
payload = payload[framelen:]
}
case tsio.ElementaryStreamTypeH264:
nalus, _ := h264parser.SplitNALUs(payload)
var sps, pps []byte
for _, nalu := range nalus {
if len(nalu) > 0 {
naltype := nalu[0] & 0x1f
switch {
case naltype == 7:
sps = nalu
case naltype == 8:
pps = nalu
case h264parser.IsDataNALU(nalu):
// raw nalu to avcc
b := make([]byte, 4+len(nalu))
pio.PutU32BE(b[0:4], uint32(len(nalu)))
copy(b[4:], nalu)
stream.addPacket(b, time.Duration(0))
n++
}
}
}
if stream.CodecData == nil && len(sps) > 0 && len(pps) > 0 {
if stream.CodecData, err = h264parser.NewCodecDataFromSPSAndPPS(sps, pps); err != nil {
return
}
}
}
return
}
func (stream *Stream) handleTSPacket(start bool, iskeyframe bool, payload []byte) (err error) {
if start {
if _, err = stream.payloadEnd(); err != nil {
return
}
var hdrlen int
if hdrlen, _, stream.datalen, stream.pts, stream.dts, err = tsio.ParsePESHeader(payload); err != nil {
return
}
stream.iskeyframe = iskeyframe
if stream.datalen == 0 {
stream.data = make([]byte, 0, 4096)
} else {
stream.data = make([]byte, 0, stream.datalen)
}
stream.data = append(stream.data, payload[hdrlen:]...)
} else {
stream.data = append(stream.data, payload...)
}
return
}