av/packet/MpegTs.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 packet

import (
	"strconv"
)

// Length of some fields in bits
const (
	SyncByteLength = 8
	TEILength      = 1
	PUSILength     = 1
	PriorityLength = 1
	PIDLength      = 13
	TSCLength      = 2
	AFCLength      = 2
	CCLength       = 4
)

// Index of the fields
const (
	SyncByteIndex = 0
	TEIIndex      = SyncByteIndex + SyncByteLength
	PUSIIndex     = TEIIndex + TEILength
	PriorityIndex = PUSIIndex + PUSILength
	PIDIndex      = PriorityIndex + PriorityLength
	TSCIndex      = PIDIndex + PIDLength
	AFCIndex      = TSCIndex + TSCLength
	CCIndex       = AFCIndex + AFCLength
	AFIndex       = CCIndex + CCLength
)

type MpegTsPacket struct {
	SyncByte byte
	TEI      bool // Transport Error Indicator
	PUSI     bool // Payload Unit Start Indicator
	Priority bool
	PID      int
	TSC      byte   // Transport Scrambling Control
	AFC      byte   // Adaption Field Control
	CC       int    // Continuity Counter
	AF       []byte // Adaption Field
	Payload  []byte
}

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

// bool to int, shift accordigly, int to string, string binary to int
func (p *MpegTsPacket) toByteSlice() (output [188]byte) {
	output[0] = p.SyncByte
	output[1] =( boolToByte(TEI) << (8-TEIIndex%8) ) | ( boolToByte(PUSI) << (8-PUSIIndex%8) ) |
	 	( boolToByte(Priority) << (8-PriorityIndex%8) ) 
}