mirror of https://bitbucket.org/ausocean/av.git
100 lines
3.0 KiB
Go
100 lines
3.0 KiB
Go
/*
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NAME
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RtpToTsConverter.go - provides utilities for the conversion of Rtp packets
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to equivalent MpegTs packets.
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DESCRIPTION
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See Readme.md
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AUTHOR
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Saxon Nelson-Milton <saxon.milton@gmail.com>
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LICENSE
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RtpToTsConverter.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with revid in gpl.txt. If not, see [GNU licenses](http://www.gnu.org/licenses).
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*/
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package packets
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import "fmt"
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type RtpToTsConverter interface {
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Convert()
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}
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type rtpToTsConverter struct {
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TsChan <-chan *MpegTsPacket
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tsChan chan<- *MpegTsPacket
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currentTsPacket *MpegTsPacket
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payloadByteChan chan byte
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currentCC byte
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}
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func NewRtpToTsConverter() (c *rtpToTsConverter) {
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c = new(rtpToTsConverter)
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tsChan := make(chan *MpegTsPacket,100)
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c.TsChan = tsChan
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c.tsChan = tsChan
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c.payloadByteChan = make(chan byte, 10000)
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c.currentCC = 0
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return
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}
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func (c* rtpToTsConverter) Convert(rtpSession *Session) {
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for {
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select{
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default:
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case rtpPacket := <-rtpSession.RtpChan:
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for ii := range rtpPacket.Payload {
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c.payloadByteChan<-rtpPacket.Payload[ii]
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}
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for len(c.payloadByteChan) > 0 {
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lengthOfByteChan := len(c.payloadByteChan)
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c.currentTsPacket = new(MpegTsPacket)
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c.currentTsPacket.SyncByte = 0x47
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c.currentTsPacket.TEI = false
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if lengthOfByteChan == len(rtpPacket.Payload) { // if it's the start of the payload
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c.currentTsPacket.PUSI = true
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} else {
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c.currentTsPacket.PUSI = false
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}
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c.currentTsPacket.Priority = false
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c.currentTsPacket.PID = 256
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c.currentTsPacket.TSC = 0
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c.currentTsPacket.AFC = 3 // adaptationfield followed by payload
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c.currentTsPacket.CC = c.currentCC
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if c.currentCC++; c.currentCC > 15 { c.currentCC = 0 }
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payloadLength := 140
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if lengthOfByteChan < 140 {
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payloadLength = lengthOfByteChan
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}
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stuffingLength := 140-payloadLength
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c.currentTsPacket.AF = make([]byte,2 + stuffingLength) // adaptationfield flag length = 16
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c.currentTsPacket.AF[0] = byte(1 + stuffingLength)
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c.currentTsPacket.AF[1] = 0
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for ii := 0; ii < stuffingLength; ii++ {
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c.currentTsPacket.AF[2+ii] = 0xFF
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}
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c.currentTsPacket.Payload = make([]byte, payloadLength)
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for ii:=0; ii < payloadLength; ii++ {
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c.currentTsPacket.Payload[ii] = <-c.payloadByteChan
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}
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c.tsChan<-c.currentTsPacket
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}
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}
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}
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}
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