/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            iso11172-1.h
 *
 *  Wed Aug 31 13:48:30 CEST 2005
 *  Copyright  2005 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of MIaV.
 *
 *  MIaV is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  MIaV 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 MIaV; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */

/*
 *  This file contains symbols used to create an ISO11172-1 compatible multiplexed 
 *  MPEG stream.
 */
#ifndef __MIAV_ISO11172_1_H__
#define __MIAV_ISO11172_1_H__

#include <stdint.h>

#define CLOCK_90KHZ 90000

namespace ISO11172_1 {
  ////////////////////////////////////////////////////
  // Types
  ////////////////////////////////////////////////////
  // 64 bits (8 bytes)
  typedef union {
    struct {
      uint64_t marker_bit3:1;
      uint64_t system_clock_reference3:15;
      uint64_t marker_bit2:1;
      uint64_t system_clock_reference2:15;
      uint64_t marker_bit1:1;
      uint64_t system_clock_reference1:3;
      uint64_t padding:4;
      uint64_t stuffing_byte:8;
      uint64_t packet_length:16;
    } bits;
    uint64_t ulli;
  } packet_header;

#define MASK3 0x7
#define MASK15 0x7FFF
#define TIMECODE32_30(x) ((x >> 30) & MASK3 )
#define TIMECODE29_15(x) ((x >> 15) & MASK15)
#define TIMECODE14_0(x)  ((x >>  0) & MASK15)

  typedef union { // <============ you are here...
    struct {
      uint64_t marker_bit5:1;
      uint64_t mux_rate:22;
      uint64_t marker_bit4:1;
      uint64_t marker_bit3:1;
      uint64_t system_clock_reference3:15;
      uint64_t marker_bit2:1;
      uint64_t system_clock_reference2:15;
      uint64_t marker_bit1:1;
      uint64_t system_clock_reference1:3;
      uint64_t padding:4;
    } bits;
    uint64_t ulli;
  } pack_header;

  typedef union {
    struct {
      uint32_t reserved_byte:8;
      uint32_t video_bound:5;
      uint32_t marker_bit:1;
      uint32_t system_video_clock_flag:1;
      uint32_t system_audio_clock_flag:1;
      uint32_t CSPS_flag:1;
      uint32_t fixed_flag:1;
      uint32_t audio_bound:6;
    } bits;
    uint32_t ulli;
  } system_header;

  typedef union {
    struct {
      uint32_t STD_buffer_size_bound:13;
      uint32_t STD_buffer_bound_scale:1;
      uint32_t market_bits:2;
      uint32_t stream_id:8;
    } bits;
    uint32_t uli;
  } stream_description;

  ////////////////////////////////////////////////////
  // Constants
  ////////////////////////////////////////////////////
  const char pack_start_code[]          = "\x00\x00\x01\xBA";
  const char system_header_start_code[] = "\x00\x00\x01\xBB";
  const char packet_start_code_prefix[] = "\x00\x00\x01";
  const char stream_id_video1[]         = "\xE3";
  const char stream_id_video2[]         = "\xE4";
  const char stream_id_video3[]         = "\xE5";
  const char stream_id_video4[]         = "\xE6";
  const char stream_id_video5[]         = "\xE7";
  const char stream_id_video6[]         = "\xE8";
  const char stream_id_video7[]         = "\xE9";
  const char stream_id_video8[]         = "\xEA";
  const char stream_id_audio1[]         = "\xC0";
  const char stream_id_audio2[]         = "\xC1";
  const char stream_id_audio3[]         = "\xC2";
  const char stream_id_audio4[]         = "\xC3";
  const char stream_id_audio5[]         = "\xC4";
  const char stream_id_audio6[]         = "\xC5";
  const char stream_id_audio7[]         = "\xC6";
  const char stream_id_audio8[]         = "\xC7";
  const char stream_id_padding[]        = "\xBE";
  const char end_code[]                 = "\x00\x00\x01\xB9";

  ////////////////////////////////////////////////////
  // Methods
  ////////////////////////////////////////////////////
  /**
   * SCR stands for System Clock Reference
   */
  inline uint32_t SCR(uint32_t previous_SCR,
                      uint32_t pack_header_size,
                      uint32_t packets_per_pack,
                      uint32_t packet_data_size,
                      uint32_t Rmux)
  {
    // To prevent a crash when doing division.
    if(Rmux == 0) Rmux = 1;
    return previous_SCR + (uint32_t)((double)(pack_header_size + 
                                              (packets_per_pack * packet_data_size)) * 
                                         (double)CLOCK_90KHZ / (double)Rmux);
  }

  /**
   * Calculates Rmux according to subclause A.6.4
   * mux stands for multiplexing and R for Rate,
   * so Rmux is the rate of the multiplexing.
   * IMPORTANT: The formula is wrong...
   * See
   *  https://www.iso.org/obp/ui/#iso:std:iso-iec:11172:-1:ed-1:v1:cor:2:v1:en
   * for the correct formula:
   * Rmux = (video_data_rate + audio_data_rate) *
   *        packet_header_size + pack_header_size / packets_per_pack
   * ( 1 + ---------------------------------------------------------- )
   *                             packet_data_size
   */
  inline uint32_t Rmux(uint32_t video_data_rate,
                       uint32_t audio_data_rate,
                       uint32_t packet_header_size,
                       uint32_t pack_header_size,
                       uint32_t packets_per_pack,
                       uint32_t packet_data_size)
  {
    // To prevent a crash when doing division.
    if(packets_per_pack == 0) packets_per_pack = 1;
    if(packet_data_size == 0) packet_data_size = 1;
    
    return (uint32_t)(
                      ((double)video_data_rate + (double)audio_data_rate) *
                      (1.0 + ((double)packet_header_size + (double)pack_header_size / (double)packets_per_pack) 
                       / (double)packet_data_size)
                      );
  }

  
};

#endif/*__MIAV_ISO11172_1_H__*/