av/h264/h264Parser.go

/*
NAME
  RtpToTsConverter.go - provides utilities for the conversion of Rtp packets
  to equivalent MpegTs packets.

DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Nelson-Milton <saxon.milton@gmail.com>

LICENSE
  RtpToTsConverter.go is Copyright (C) 2017 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 [GNU licenses](http://www.gnu.org/licenses).
*/

package h264

import (
  "bitbucket.org/ausocean/av/itut"
  "log"
  "sync"
  _"fmt"
  _"time"
)

const (
	acceptedLength = 1000
)

var (
	Info *log.Logger
	mutex  *sync.Mutex
)

type H264Parser struct {
  inputBuffer []byte
  isParsing bool
  OutputChan chan<- []byte
  InputByteChan chan byte
}

func (p* H264Parser)Stop(){
  p.isParsing = false
}

func (p* H264Parser)Parse() {
	p.isParsing = true
	outputBuffer := make([]byte, 0, 10000)
	searchingForEnd := false
	p.InputByteChan = make(chan byte, 10000)
	for p.isParsing {
    aByte := <-p.InputByteChan
		outputBuffer = append(outputBuffer, aByte)
		for i:=1; aByte == 0x00 && i != 4; i++ {
			aByte = <-p.InputByteChan
			outputBuffer = append(outputBuffer, aByte)
			if ( aByte == 0x01 && i == 2 ) || ( aByte == 0x01 && i == 3 ) {
				if searchingForEnd {
          output := append(append(itut.StartCode1(),itut.AUD()...),outputBuffer[:len(outputBuffer)-(i+1)]...)
					p.OutputChan<-output
					outputBuffer = outputBuffer[len(outputBuffer)-1-i:]
					searchingForEnd = false
				}
				aByte = <-p.InputByteChan
				outputBuffer = append(outputBuffer, aByte)
				if nalType := aByte & 0x1F; nalType == 1 || nalType == 5 {
					searchingForEnd = true
				}
			}
		}
	}
}