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Merged in gardening/tsgen (pull request #44) 

generator: clean up MPEG-TS encoding

Approved-by: Alan Noble <anoble@gmail.com>
This commit is contained in:
kortschak 2018-08-19 08:45:29 +00:00 committed by Alan Noble
parent 05b9416aa4 7ee79ad0be
commit 9e28fd45fd
4 changed files with 276 additions and 180 deletions
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369
generator/mpegts_generator.go
View File

@ -6,10 +6,11 @@ DESCRIPTION
See Readme.md
AUTHOR
Dan Kortschak <dan@ausocean.org>
Saxon Nelson-Milton <saxon@ausocean.org>
LICENSE
mpegts_generator.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
mpegts_generator.go is Copyright (C) 2017-2018 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
@ -22,11 +23,17 @@ LICENSE
for more details.
You should have received a copy of the GNU General Public License
along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package generator
import (
"encoding/binary"
"hash/crc32"
"math/bits"
"time"
"bitbucket.org/ausocean/av/mpegts"
"bitbucket.org/ausocean/av/pes"
)
@ -35,51 +42,156 @@ const psiPacketSize = 184
// TODO: really need to finish the at and pmt stuff - this is too hacky
var (
patTable = []byte{0, 0, 176, 13, 0, 1, 193, 0, 0, 0, 1, 240, 0, 42, 177, 4, 178}
pmtTable = []byte{0, 2, 176, 18, 0, 1, 193, 0, 0, 0xE1, 0x00, 0xF0, 0, 0x1B, 0xE1, 0, 0xF0, 0, 0x15, 0xBD, 0x4D, 0x56}
patTable = []byte{
0x00, // pointer
// ---- section included in data sent to CRC32 during check
// table header
0x00, // table id
0xb0, // section syntax indicator:1|private bit:1|reserved:2|section length:2|more bytes...:2
0x0d, // more bytes...
// syntax section
0x00, 0x01, // table id extension
0xc1, // reserved bits:3|version:5|use now:1
0x00, // section number
0x00, // last section number
// table data
0x00, 0x01, // Program number
0xf0, 0x00, // reserved:3|program map PID:13
// 0x2a, 0xb1, 0x04, 0xb2, // CRC
// ----
}
pmtTable = []byte{
0x00, // pointer
// ---- section included in data sent to CRC32 during check
// table header
0x02, // table id
0xb0, // section syntax indicator:1|private bit:1|reserved:2|section length:2|more bytes...:2
0x12, // more bytes...
// syntax section
0x00, 0x01, // table id extension
0xc1, // reserved bits:3|version:5|use now:1
0x00, // section number
0x00, // last section number
// table data
0xe1, 0x00, // reserved:3|PCR PID:13
0xf0, 0x00, // reserved:4|unused:2|program info length:10
// No program descriptors since program info length is 0.
// elementary stream info data
0x1b, // stream type
0xe1, 0x00, // reserved:3|elementary PID:13
0xf0, 0x00, // reserved:4|unused:2|ES info length:10
// No elementary stream descriptors since ES info length is 0.
// 0x15, 0xbd, 0x4d, 0x56, // CRC
// ----
}
)
// genPatAndPmt generates the rest of the pat and pmt tables i.e. fills them
// with 0xFFs - because it looks ugly to hardcode above. This is called through
// NewMpegtsgenerator
func genPatAndPmt() {
for len(patTable) < psiPacketSize {
patTable = append(patTable, 255)
func init() {
// Generate IEEE polynomial table
// for the big-endian algorithm.
crcTable := crc32_MakeTable(bits.Reverse32(crc32.IEEE))
patTable = completePSI(patTable, crcTable)
pmtTable = completePSI(pmtTable, crcTable)
}
func completePSI(psi []byte, tab *crc32.Table) []byte {
var buf [4]byte
crc := crc32_Update(0xffffffff, tab, psi[1:])
binary.BigEndian.PutUint32(buf[:], crc)
dst := make([]byte, len(psi), psiPacketSize)
copy(dst, psi)
dst = append(dst, buf[:]...)
for len(dst) < cap(dst) {
dst = append(dst, 0xff)
}
for len(pmtTable) < psiPacketSize {
pmtTable = append(pmtTable, 255)
return dst
}
func crc32_MakeTable(poly uint32) *crc32.Table {
var t crc32.Table
for i := range t {
crc := uint32(i) << 24
for j := 0; j < 8; j++ {
if crc&0x80000000 != 0 {
crc = (crc << 1) ^ poly
} else {
crc <<= 1
}
}
t[i] = crc
}
return &t
}
func crc32_Update(crc uint32, tab *crc32.Table, p []byte) uint32 {
for _, v := range p {
crc = tab[byte(crc>>24)^v] ^ (crc << 8)
}
return crc
}
const (
SdtPid = 17
PatPid = 0
pmtPid = 4096
videoPid = 256
streamID = 0xE0
outputChanSize = 100
inputChanSize = 10000
pesPktChanSize = 1000
payloadByteChanSize = 200000
ptsOffset = .7
maxCC = 15
sdtPid = 17
patPid = 0
pmtPid = 4096
videoPid = 256
streamID = 0xe0 // First video stream ID.
)
// Time related constants.
const (
// ptsOffset is the offset added to the clock to determine
// the current presentation timestamp,
ptsOffset = 700 * time.Millisecond
// pcrFreq is the base Program Clock Reference frequency.
pcrFreq = 90000 // Hz
)
// tsGenerator encapsulates properties of an mpegts generator.
type tsGenerator struct {
outputChan chan []byte
nalInputChan chan []byte
currentTsPacket *mpegts.MpegTsPacket
payloadByteChan chan byte
currentCC byte
currentPtsTime float64
currentPcrTime float64
fps uint
pesPktChan chan []byte
ccMap map[int]int
isGenerating bool
outputChan chan []byte
nalInputChan chan []byte
clock time.Duration
frameInterval time.Duration
ptsOffset time.Duration
continuity map[int]byte
}
// NewTsGenerator returns an instance of the tsGenerator struct
func NewTsGenerator(fps float64) (g *tsGenerator) {
return &tsGenerator{
outputChan: make(chan []byte, 1),
nalInputChan: make(chan []byte, 1),
frameInterval: time.Duration(float64(time.Second) / fps),
ptsOffset: ptsOffset,
continuity: map[int]byte{
patPid: 0,
pmtPid: 0,
videoPid: 0,
},
}
}
// Start is called when we would like generation to begin, i.e. we would like
// the generator to start taking input data and creating mpegts packets
func (g *tsGenerator) Start() {
go g.generate()
}
func (g *tsGenerator) Stop() {}
// InputChan returns a handle to the nalInputChan (inputChan) so that nal units
// can be passed to the generator and processed
func (g *tsGenerator) InputChan() chan []byte {
@ -92,117 +204,98 @@ func (g *tsGenerator) OutputChan() <-chan []byte {
return g.outputChan
}
// NewTsGenerator returns an instance of the tsGenerator struct
func NewTsGenerator(fps uint) (g *tsGenerator) {
g = new(tsGenerator)
g.outputChan = make(chan []byte, outputChanSize)
g.nalInputChan = make(chan []byte, inputChanSize)
g.currentCC = 0
g.fps = fps
g.currentPcrTime = 0.0
g.currentPtsTime = ptsOffset
g.pesPktChan = make(chan []byte, pesPktChanSize)
g.payloadByteChan = make(chan byte, payloadByteChanSize)
g.ccMap = make(map[int]int, 4)
g.ccMap[SdtPid] = 0
g.ccMap[PatPid] = 0
g.ccMap[pmtPid] = 0
g.ccMap[videoPid] = 0
genPatAndPmt()
g.isGenerating = false
return
}
const (
hasPayload = 0x1
hasAdaptationField = 0x2
)
// getPts retuns the next presentation timestamp for the tsGenerator t.
func (g *tsGenerator) genPts() (pts uint64) {
pts = uint64(g.currentPtsTime * float64(90000))
g.currentPtsTime += 1.0 / float64(g.fps)
return
}
// genPcr returns the next program clock reference for the tsGenerator g
func (g *tsGenerator) genPcr() (pcr uint64) {
pcr = uint64(g.currentPcrTime * float64(90000))
g.currentPcrTime += 1.0 / float64(g.fps)
return
}
// Start is called when we would like generation to begin, i.e. we would like
// the generator to start taking input data and creating mpegts packets
func (g *tsGenerator) Start() {
g.isGenerating = true
go g.generate()
}
func (g *tsGenerator) Stop() {
g.isGenerating = false
}
// getCC returns the next continuity counter for a particular pid
func (g *tsGenerator) getCC(pid int) int {
temp := g.ccMap[pid]
if g.ccMap[pid]++; g.ccMap[pid] > maxCC {
g.ccMap[pid] = 0
}
return temp
}
const (
hasDTS = 0x1
hasPTS = 0x2
)
// generate handles the incoming data and generates equivalent mpegts packets -
// sending them to the output channel
func (g *tsGenerator) generate() {
for {
select {
case nalUnit := <-g.nalInputChan:
pesPkt := pes.PESPacket{
StreamID: streamID,
PDI: byte(2),
PTS: g.genPts(),
Data: nalUnit,
HeaderLength: 5,
}
pesPktSlice := pesPkt.ToByteSlice()
nalu := <-g.nalInputChan
for ii := range pesPktSlice {
g.payloadByteChan <- pesPktSlice[ii]
}
pusi := true
for len(g.payloadByteChan) > 0 {
pkt := mpegts.MpegTsPacket{
PUSI: pusi,
PID: videoPid,
RAI: pusi,
CC: byte(g.getCC(videoPid)),
AFC: byte(3),
PCRF: pusi,
}
pkt.FillPayload(g.payloadByteChan)
// TODO: create consts for AFC parameters
if pusi {
// Create pat table
patPkt := mpegts.MpegTsPacket{
PUSI: pusi,
PID: PatPid,
CC: byte(g.getCC(PatPid)),
AFC: 1,
Payload: patTable,
}
g.outputChan <- patPkt.ToByteSlice()
// Create pmt table
pmtPkt := mpegts.MpegTsPacket{
PUSI: pusi,
PID: pmtPid,
CC: byte(g.getCC(pmtPid)),
AFC: 1,
Payload: pmtTable,
}
g.outputChan <- pmtPkt.ToByteSlice()
// If pusi then we need to gen a pcr
pkt.PCR = g.genPcr()
pusi = false
}
g.outputChan <- pkt.ToByteSlice()
}
// Write PAT
patPkt := mpegts.Packet{
PUSI: true,
PID: patPid,
CC: g.ccFor(patPid),
AFC: hasPayload,
Payload: patTable,
}
g.outputChan <- patPkt.Bytes()
// Write PMT.
pmtPkt := mpegts.Packet{
PUSI: true,
PID: pmtPid,
CC: g.ccFor(pmtPid),
AFC: hasPayload,
Payload: pmtTable,
}
g.outputChan <- pmtPkt.Bytes()
// Prepare PES data.
pesPkt := pes.Packet{
StreamID: streamID,
PDI: hasPTS,
PTS: g.pts(),
Data: nalu,
HeaderLength: 5,
}
buf := pesPkt.Bytes()
pusi := true
for len(buf) != 0 {
pkt := mpegts.Packet{
PUSI: pusi,
PID: videoPid,
RAI: pusi,
CC: g.ccFor(videoPid),
AFC: hasAdaptationField | hasPayload,
PCRF: pusi,
}
n := pkt.FillPayload(buf)
buf = buf[n:]
if pusi {
// If the packet has a Payload Unit Start Indicator
// flag set then we need to write a PCR.
pkt.PCR = g.pcr()
pusi = false
}
g.outputChan <- pkt.Bytes()
}
g.tick()
}
}
// tick advances the clock one frame interval.
func (g *tsGenerator) tick() {
g.clock += g.frameInterval
}
// pts retuns the current presentation timestamp.
func (g *tsGenerator) pts() uint64 {
return uint64((g.clock + g.ptsOffset).Seconds() * pcrFreq)
}
// pcr returns the current program clock reference.
func (g *tsGenerator) pcr() uint64 {
return uint64(g.clock.Seconds() * pcrFreq)
}
// ccFor returns the next continuity counter for pid.
func (g *tsGenerator) ccFor(pid int) byte {
cc := g.continuity[pid]
const continuityCounterMask = 0xf
g.continuity[pid] = (cc + 1) & continuityCounterMask
return cc
}

71
mpegts/MpegTs.go
View File

@ -28,8 +28,6 @@ LICENSE
package mpegts
import "bitbucket.org/ausocean/av/tools"
const (
mpegTsSize = 188
mpegtsPayloadSize = 176
@ -100,7 +98,7 @@ the formatting of an MPEG-TS packet for reference!
| - | ... |
----------------------------------------------------------------------------
*/
type MpegTsPacket struct {
type Packet struct {
TEI bool // Transport Error Indicator
PUSI bool // Payload Unit Start Indicator
Priority bool // Tranposrt priority indicator
@ -127,27 +125,32 @@ type MpegTsPacket struct {
// FillPayload takes a channel and fills the packets Payload field until the
// channel is empty or we've the packet reaches capacity
func (p *MpegTsPacket) FillPayload(channel chan byte) {
p.Payload = make([]byte, 0, mpegtsPayloadSize)
currentPktLength := 6 + int(toByte(p.PCRF))*6 + int(toByte(p.OPCRF))*6 +
int(toByte(p.SPF))*1 + int(toByte(p.TPDF))*1 + len(p.TPD)
// While we're within the mpegts packet size and we still have data we can use
for (currentPktLength+len(p.Payload)) < mpegTsSize && len(channel) > 0 {
p.Payload = append(p.Payload, <-channel)
}
func (p *Packet) FillPayload(data []byte) int {
currentPktLength := 6 + asInt(p.PCRF)*6 + asInt(p.OPCRF)*6 +
asInt(p.SPF)*1 + asInt(p.TPDF)*1 + len(p.TPD)
p.Payload = make([]byte, mpegtsPayloadSize-currentPktLength)
return copy(p.Payload, data)
}
// toByte is a simple wrapper function for tools.BoolToByte which takes a bool
// and returns an equivalent byte
func toByte(b bool) byte {
return tools.BoolToByte(b)
func asInt(b bool) int {
if b {
return 1
}
return 0
}
func asByte(b bool) byte {
if b {
return 1
}
return 0
}
// ToByteSlice interprets the fields of the ts packet instance and outputs a
// corresponding byte slice
func (p *MpegTsPacket) ToByteSlice() (output []byte) {
stuffingLength := 182 - len(p.Payload) - len(p.TPD) - int(toByte(p.PCRF))*6 -
int(toByte(p.OPCRF))*6 - int(toByte(p.SPF))
func (p *Packet) Bytes() []byte {
stuffingLength := 182 - len(p.Payload) - len(p.TPD) - asInt(p.PCRF)*6 -
asInt(p.OPCRF)*6 - asInt(p.SPF)
var stuffing []byte
if stuffingLength > 0 {
stuffing = make([]byte, stuffingLength)
@ -155,36 +158,36 @@ func (p *MpegTsPacket) ToByteSlice() (output []byte) {
for i := range stuffing {
stuffing[i] = 0xFF
}
afl := 1 + int(toByte(p.PCRF))*6 + int(toByte(p.OPCRF))*6 + int(toByte(p.SPF)) + int(toByte(p.TPDF)) + len(p.TPD) + len(stuffing)
output = make([]byte, 0, mpegTsSize)
output = append(output, []byte{
afl := 1 + asInt(p.PCRF)*6 + asInt(p.OPCRF)*6 + asInt(p.SPF) + asInt(p.TPDF) + len(p.TPD) + len(stuffing)
buf := make([]byte, 0, mpegTsSize)
buf = append(buf, []byte{
0x47,
(toByte(p.TEI)<<7 | toByte(p.PUSI)<<6 | toByte(p.Priority)<<5 | byte((p.PID&0xFF00)>>8)),
(asByte(p.TEI)<<7 | asByte(p.PUSI)<<6 | asByte(p.Priority)<<5 | byte((p.PID&0xFF00)>>8)),
byte(p.PID & 0x00FF),
(p.TSC<<6 | p.AFC<<4 | p.CC),
}...)
if p.AFC == 3 || p.AFC == 2 {
output = append(output, []byte{
byte(afl), (toByte(p.DI)<<7 | toByte(p.RAI)<<6 | toByte(p.ESPI)<<5 |
toByte(p.PCRF)<<4 | toByte(p.OPCRF)<<3 | toByte(p.SPF)<<2 |
toByte(p.TPDF)<<1 | toByte(p.AFEF)),
buf = append(buf, []byte{
byte(afl), (asByte(p.DI)<<7 | asByte(p.RAI)<<6 | asByte(p.ESPI)<<5 |
asByte(p.PCRF)<<4 | asByte(p.OPCRF)<<3 | asByte(p.SPF)<<2 |
asByte(p.TPDF)<<1 | asByte(p.AFEF)),
}...)
for i := 40; p.PCRF && i >= 0; i -= 8 {
output = append(output, byte((p.PCR<<15)>>uint(i)))
buf = append(buf, byte((p.PCR<<15)>>uint(i)))
}
for i := 40; p.OPCRF && i >= 0; i -= 8 {
output = append(output, byte(p.OPCR>>uint(i)))
buf = append(buf, byte(p.OPCR>>uint(i)))
}
if p.SPF {
output = append(output, p.SC)
buf = append(buf, p.SC)
}
if p.TPDF {
output = append(output, append([]byte{p.TPDL}, p.TPD...)...)
buf = append(buf, append([]byte{p.TPDL}, p.TPD...)...)
}
output = append(output, p.Ext...)
output = append(output, stuffing...)
buf = append(buf, p.Ext...)
buf = append(buf, stuffing...)
}
output = append(output, p.Payload...)
return
buf = append(buf, p.Payload...)
return buf
}

14
pes/pes.go
View File

@ -70,7 +70,7 @@ the formatting of a PES packet for reference!
----------------------------------------------------------------------------
*/
// TODO: add DSMTM, ACI, CRC, Ext fields
type PESPacket struct {
type Packet struct {
StreamID byte // Type of stream
Length uint16 // Pes packet length in bytes after this field
SC byte // Scrambling control
@ -94,9 +94,9 @@ type PESPacket struct {
Data []byte // Pes packet data
}
func (p *PESPacket) ToByteSlice() (output []byte) {
output = make([]byte, 0, maxPesSize)
output = append(output, []byte{
func (p *Packet) Bytes() []byte {
buf := make([]byte, 0, maxPesSize)
buf = append(buf, []byte{
0x00, 0x00, 0x01,
p.StreamID,
byte((p.Length & 0xFF00) >> 8),
@ -110,7 +110,7 @@ func (p *PESPacket) ToByteSlice() (output []byte) {
if p.PDI == byte(2) {
pts := 0x2100010001 | (p.PTS&0x1C0000000)<<3 | (p.PTS&0x3FFF8000)<<2 |
(p.PTS&0x7FFF)<<1
output = append(output, []byte{
buf = append(buf, []byte{
byte((pts & 0xFF00000000) >> 32),
byte((pts & 0x00FF000000) >> 24),
byte((pts & 0x0000FF0000) >> 16),
@ -118,6 +118,6 @@ func (p *PESPacket) ToByteSlice() (output []byte) {
byte(pts & 0x00000000FF),
}...)
}
output = append(output, append(p.Stuff, p.Data...)...)
return
buf = append(buf, append(p.Stuff, p.Data...)...)
return buf
}

2
revid/revid.go
View File

@ -209,7 +209,7 @@ func (r *Revid) reset(config Config) error {
case Mpegts:
r.Log(Info, "Using MPEGTS packetisation")
frameRate, _ := strconv.Atoi(r.config.FrameRate)
r.generator = generator.NewTsGenerator(uint(frameRate))
r.generator = generator.NewTsGenerator(float64(frameRate))
case Flv:
r.Log(Info, "Using FLV packetisation")
frameRate, _ := strconv.Atoi(r.config.FrameRate)