av/packets/helpers.go

/*
NAME
  MpegTs.go - provides a data structure intended to encapsulate the properties
  of an MpegTs packet.

DESCRIPTION
  See Readme.md

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

LICENSE
  MpegTs.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 packets

import (
	_"os"
	_"fmt"
	"reflect"
)

func boolToByte(in bool) (out uint8) {
	if in {
		out = 1
	}
	return
}

func GetOctectType(p *RtpPacket) byte {
	return p.Payload[0] & 0x1F
}

func GetStartBit(p *RtpPacket) byte {
	return (p.Payload[1] & 0x80) >> 7
}

func getEndBit(p *RtpPacket) byte {
	return (p.Payload[1] & 0x40) >> 6
}

func ParseH264Buffer(buffer []byte, outputChan chan<- []byte) {
	startCode1 := []byte{0x00,0x00,0x01}
	startCode2 := []byte{0x00,0x00,0x00,0x01}
	for i := 0; i < len(buffer); i++ {
		var start bool
		i, start = func() (int,bool) {
			switch{
			case reflect.DeepEqual(buffer[i:i+3],startCode1):
				return i+3, true
			case reflect.DeepEqual(buffer[i:i+4],startCode2):
				return i+4, true
			}
				return i, false
		}()
		if nalType := buffer[i] & 0x1F; start && ( nalType == 1 || nalType == 5) {
			for ; i < len(buffer) && !(i+3 < len(buffer) && ( reflect.DeepEqual(buffer[i:i+3],startCode1) ||
				reflect.DeepEqual(buffer[i:i+4],startCode2))); i++ {}
			outputChan<-append(append(startCode1,[]byte{0x09,0xF0}...),buffer[:i]...)
			buffer = buffer[i:]
			i=0
		}
	}
}