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mts: Added audio mts encoding and test

This commit is contained in:
Trek H 2019-04-05 16:28:25 +10:30
parent 2d15e98445
commit 78447ed495
5 changed files with 170 additions and 31 deletions
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109
container/mts/audio_test.go Normal file
View File

@ -0,0 +1,109 @@
/*
NAME
audio_test.go
DESCRIPTION
See Readme.md
AUTHOR
Trek Hopton <trek@ausocean.org>
LICENSE
audio_test.go is Copyright (C) 2017-2019 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
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 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.
*/
package mts
import (
"bytes"
"io/ioutil"
"log"
"testing"
"bitbucket.org/ausocean/av/container/mts/meta"
"github.com/Comcast/gots/packet"
"github.com/Comcast/gots/pes"
)
// TestEncodePcm tests the mpegts encoder's ability to encode pcm audio data.
// It reads and encodes input pcm data into mpegts, then decodes the mpegts compares the result to the input pcm.
func TestEncodePcm(t *testing.T) {
Meta = meta.New()
var b []byte
buf := bytes.NewBuffer(b)
sampleRate := 48000
sampleSize := 2
writeSize := 16000
writeFreq := float64(sampleRate*sampleSize) / float64(writeSize)
e := NewEncoder(buf, writeFreq, Audio)
inPath := "../../../test/test-data/av/input/sweep_400Hz_20000Hz_-3dBFS_5s_48khz.pcm"
inPcm, err := ioutil.ReadFile(inPath)
if err != nil {
log.Fatal(err)
}
// Encode pcm to mts and get the resulting bytes.
_, err = e.Write(inPcm)
if err != nil {
log.Fatal(err)
}
clip := buf.Bytes()
// Decode the mts packets to extract the original data
var pkt packet.Packet
pesPacket := make([]byte, 0, writeSize)
got := make([]byte, 0, len(inPcm))
i := 0
for i+PacketSize <= len(clip) {
copy(pkt[:], clip[i:i+PacketSize])
if pkt.PID() == audioPid {
if pkt.PayloadUnitStartIndicator() {
payload, err := pkt.Payload()
if err != nil {
t.Fatalf("Unexpected err: %v\n", err)
}
pesPacket = append(pesPacket, payload...)
i += PacketSize
first := true
for (first || !pkt.PayloadUnitStartIndicator()) && i+PacketSize <= len(clip) {
first = false
copy(pkt[:], clip[i:i+PacketSize])
payload, err := pkt.Payload()
if err != nil {
t.Fatalf("Unexpected err: %v\n", err)
}
pesPacket = append(pesPacket, payload...)
i += PacketSize
}
}
pesHeader, err := pes.NewPESHeader(pesPacket)
if err != nil {
t.Fatalf("Unexpected err: %v\n", err)
}
got = append(got, pesHeader.Data()...)
} else {
i += PacketSize
}
}
// Compare encoded data with original data.
if !bytes.Equal(got, inPcm) {
t.Error("Error, unexpected output")
}
}

76
container/mts/encoder.go
View File

@ -101,11 +101,20 @@ var (
)
const (
sdtPid = 17
patPid = 0
pmtPid = 4096
videoPid = 256
streamID = 0xe0 // First video stream ID.
sdtPid = 17
patPid = 0
pmtPid = 4096
videoPid = 256
audioPid = 210
videoStreamID = 0xe0 // First video stream ID.
audioStreamID = 0xc0 // First audio stream ID.
)
// Video and Audio constants are used to communicate which media type will be encoded when creating a
// new encoder with NewEncoder.
const (
Video = iota
Audio
)
// Time related constants.
@ -122,38 +131,54 @@ const (
type Encoder struct {
dst io.Writer
clock time.Duration
lastTime time.Time
frameInterval time.Duration
ptsOffset time.Duration
tsSpace [PacketSize]byte
pesSpace [pes.MaxPesSize]byte
clock time.Duration
lastTime time.Time
writePeriod time.Duration
ptsOffset time.Duration
tsSpace [PacketSize]byte
pesSpace [pes.MaxPesSize]byte
continuity map[int]byte
timeBasedPsi bool
pktCount int
psiSendCount int
mediaPid int
streamID byte
psiLastTime time.Time
}
// NewEncoder returns an Encoder with the specified frame rate.
func NewEncoder(dst io.Writer, fps float64) *Encoder {
func NewEncoder(dst io.Writer, writeFreq float64, mediaType int) *Encoder {
var mPid int
var sid byte
switch mediaType {
case Audio:
mPid = audioPid
sid = audioStreamID
case Video:
mPid = videoPid
sid = videoStreamID
}
return &Encoder{
dst: dst,
frameInterval: time.Duration(float64(time.Second) / fps),
ptsOffset: ptsOffset,
writePeriod: time.Duration(float64(time.Second) / writeFreq),
ptsOffset: ptsOffset,
timeBasedPsi: true,
pktCount: 8,
mediaPid: mPid,
streamID: sid,
continuity: map[int]byte{
patPid: 0,
pmtPid: 0,
videoPid: 0,
patPid: 0,
pmtPid: 0,
mPid: 0,
},
}
}
@ -180,7 +205,7 @@ func (e *Encoder) TimeBasedPsi(b bool, sendCount int) {
// Write implements io.Writer. Write takes raw h264 and encodes into mpegts,
// then sending it to the encoder's io.Writer destination.
func (e *Encoder) Write(nalu []byte) (int, error) {
func (e *Encoder) Write(data []byte) (int, error) {
now := time.Now()
if (e.timeBasedPsi && (now.Sub(e.psiLastTime) > psiInterval)) || (!e.timeBasedPsi && (e.pktCount >= e.psiSendCount)) {
e.pktCount = 0
@ -193,21 +218,22 @@ func (e *Encoder) Write(nalu []byte) (int, error) {
// Prepare PES data.
pesPkt := pes.Packet{
StreamID: streamID,
StreamID: e.streamID,
PDI: hasPTS,
PTS: e.pts(),
Data: nalu,
Data: data,
HeaderLength: 5,
}
buf := pesPkt.Bytes(e.pesSpace[:pes.MaxPesSize])
pusi := true
for len(buf) != 0 {
pkt := Packet{
PUSI: pusi,
PID: videoPid,
PID: uint16(e.mediaPid),
RAI: pusi,
CC: e.ccFor(videoPid),
CC: e.ccFor(e.mediaPid),
AFC: hasAdaptationField | hasPayload,
PCRF: pusi,
}
@ -222,14 +248,14 @@ func (e *Encoder) Write(nalu []byte) (int, error) {
}
_, err := e.dst.Write(pkt.Bytes(e.tsSpace[:PacketSize]))
if err != nil {
return len(nalu), err
return len(data), err
}
e.pktCount++
}
e.tick()
return len(nalu), nil
return len(data), nil
}
// writePSI creates mpegts with pat and pmt tables - with pmt table having updated
@ -271,7 +297,7 @@ func (e *Encoder) writePSI() error {
// tick advances the clock one frame interval.
func (e *Encoder) tick() {
e.clock += e.frameInterval
e.clock += e.writePeriod
}
// pts retuns the current presentation timestamp.

4
container/mts/metaEncode_test.go
View File

@ -49,7 +49,7 @@ func TestMetaEncode1(t *testing.T) {
Meta = meta.New()
var b []byte
buf := bytes.NewBuffer(b)
e := NewEncoder(buf, fps)
e := NewEncoder(buf, fps, Video)
Meta.Add("ts", "12345678")
if err := e.writePSI(); err != nil {
t.Errorf(errUnexpectedErr, err.Error())
@ -78,7 +78,7 @@ func TestMetaEncode2(t *testing.T) {
Meta = meta.New()
var b []byte
buf := bytes.NewBuffer(b)
e := NewEncoder(buf, fps)
e := NewEncoder(buf, fps, Video)
Meta.Add("ts", "12345678")
Meta.Add("loc", "1234,4321,1234")
if err := e.writePSI(); err != nil {

10
container/mts/mpegts.go
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@ -74,7 +74,7 @@ const (
)
/*
The below data struct encapsulates the fields of an MPEG-TS packet. Below is
Packet encapsulates the fields of an MPEG-TS packet. Below is
the formatting of an MPEG-TS packet for reference!
MPEG-TS Packet Formatting
@ -196,7 +196,11 @@ func FindPid(d []byte, pid uint16) (pkt []byte, i int, err error) {
func (p *Packet) FillPayload(data []byte) int {
currentPktLen := 6 + asInt(p.PCRF)*6 + asInt(p.OPCRF)*6 +
asInt(p.SPF)*1 + asInt(p.TPDF)*1 + len(p.TPD)
p.Payload = make([]byte, PayloadSize-currentPktLen)
if len(data) > PayloadSize-currentPktLen {
p.Payload = make([]byte, PayloadSize-currentPktLen)
} else {
p.Payload = make([]byte, len(data))
}
return copy(p.Payload, data)
}
@ -214,7 +218,7 @@ func asByte(b bool) byte {
return 0
}
// ToByteSlice interprets the fields of the ts packet instance and outputs a
// Bytes interprets the fields of the ts packet instance and outputs a
// corresponding byte slice
func (p *Packet) Bytes(buf []byte) []byte {
if buf == nil || cap(buf) != PacketSize {

2
container/mts/pes/pes.go
View File

@ -26,7 +26,7 @@ LICENSE
package pes
const MaxPesSize = 10000
const MaxPesSize = 65536
/*
The below data struct encapsulates the fields of an PES packet. Below is