Rev 1624 | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1624 | giacomo | 1 | /* systems.c, systems-specific routines */ |
| 2 | |||
| 3 | /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ |
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| 4 | |||
| 5 | /* |
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| 6 | * Disclaimer of Warranty |
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| 7 | * |
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| 8 | * These software programs are available to the user without any license fee or |
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| 9 | * royalty on an "as is" basis. The MPEG Software Simulation Group disclaims |
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| 10 | * any and all warranties, whether express, implied, or statuary, including any |
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| 11 | * implied warranties or merchantability or of fitness for a particular |
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| 12 | * purpose. In no event shall the copyright-holder be liable for any |
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| 13 | * incidental, punitive, or consequential damages of any kind whatsoever |
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| 14 | * arising from the use of these programs. |
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| 15 | * |
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| 16 | * This disclaimer of warranty extends to the user of these programs and user's |
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| 17 | * customers, employees, agents, transferees, successors, and assigns. |
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| 18 | * |
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| 19 | * The MPEG Software Simulation Group does not represent or warrant that the |
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| 20 | * programs furnished hereunder are free of infringement of any third-party |
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| 21 | * patents. |
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| 22 | * |
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| 23 | * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, |
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| 24 | * are subject to royalty fees to patent holders. Many of these patents are |
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| 25 | * general enough such that they are unavoidable regardless of implementation |
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| 26 | * design. |
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| 27 | * |
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| 28 | */ |
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| 29 | |||
| 30 | #include <stdio.h> |
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| 31 | #include <stdlib.h> |
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| 32 | |||
| 33 | #include "config.h" |
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| 34 | #include "global.h" |
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| 35 | |||
| 36 | /* initialize buffer, call once before first getbits or showbits */ |
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| 37 | |||
| 38 | /* parse system layer, ignore everything we don't need */ |
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| 39 | void Next_Packet() |
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| 40 | { |
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| 41 | unsigned int code; |
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| 42 | int l; |
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| 43 | |||
| 44 | for(;;) |
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| 45 | { |
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| 46 | code = Get_Long(); |
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| 47 | |||
| 48 | /* remove system layer byte stuffing */ |
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| 49 | while ((code & 0xffffff00) != 0x100) |
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| 50 | code = (code<<8) | Get_Byte(); |
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| 51 | |||
| 52 | switch(code) |
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| 53 | { |
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| 54 | case PACK_START_CODE: /* pack header */ |
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| 55 | /* skip pack header (system_clock_reference and mux_rate) */ |
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| 56 | ld->Rdptr += 8; |
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| 57 | break; |
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| 58 | case VIDEO_ELEMENTARY_STREAM: |
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| 59 | code = Get_Word(); /* packet_length */ |
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| 60 | ld->Rdmax = ld->Rdptr + code; |
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| 61 | |||
| 62 | code = Get_Byte(); |
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| 63 | |||
| 64 | if((code>>6)==0x02) |
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| 65 | { |
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| 66 | ld->Rdptr++; |
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| 67 | code=Get_Byte(); /* parse PES_header_data_length */ |
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| 68 | ld->Rdptr+=code; /* advance pointer by PES_header_data_length */ |
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| 69 | printf("MPEG-2 PES packet\n"); |
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| 70 | return; |
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| 71 | } |
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| 72 | else if(code==0xff) |
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| 73 | { |
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| 74 | /* parse MPEG-1 packet header */ |
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| 75 | while((code=Get_Byte())== 0xFF); |
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| 76 | } |
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| 77 | |||
| 78 | /* stuffing bytes */ |
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| 79 | if(code>=0x40) |
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| 80 | { |
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| 81 | if(code>=0x80) |
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| 82 | { |
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| 83 | fprintf(stderr,"Error in packet header\n"); |
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| 84 | exit(1); |
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| 85 | } |
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| 86 | /* skip STD_buffer_scale */ |
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| 87 | ld->Rdptr++; |
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| 88 | code = Get_Byte(); |
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| 89 | } |
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| 90 | |||
| 91 | if(code>=0x30) |
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| 92 | { |
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| 93 | if(code>=0x40) |
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| 94 | { |
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| 95 | fprintf(stderr,"Error in packet header\n"); |
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| 96 | exit(1); |
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| 97 | } |
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| 98 | /* skip presentation and decoding time stamps */ |
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| 99 | ld->Rdptr += 9; |
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| 100 | } |
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| 101 | else if(code>=0x20) |
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| 102 | { |
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| 103 | /* skip presentation time stamps */ |
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| 104 | ld->Rdptr += 4; |
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| 105 | } |
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| 106 | else if(code!=0x0f) |
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| 107 | { |
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| 108 | fprintf(stderr,"Error in packet header\n"); |
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| 109 | exit(1); |
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| 110 | } |
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| 111 | return; |
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| 112 | case ISO_END_CODE: /* end */ |
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| 113 | /* simulate a buffer full of sequence end codes */ |
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| 114 | l = 0; |
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| 115 | while (l<2048) |
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| 116 | { |
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| 117 | ld->Rdbfr[l++] = SEQUENCE_END_CODE>>24; |
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| 118 | ld->Rdbfr[l++] = SEQUENCE_END_CODE>>16; |
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| 119 | ld->Rdbfr[l++] = SEQUENCE_END_CODE>>8; |
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| 120 | ld->Rdbfr[l++] = SEQUENCE_END_CODE&0xff; |
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| 121 | } |
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| 122 | ld->Rdptr = ld->Rdbfr; |
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| 123 | ld->Rdmax = ld->Rdbfr + 2048; |
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| 124 | return; |
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| 125 | default: |
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| 126 | if(code>=SYSTEM_START_CODE) |
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| 127 | { |
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| 128 | /* skip system headers and non-video packets*/ |
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| 129 | code = Get_Word(); |
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| 130 | ld->Rdptr += code; |
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| 131 | } |
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| 132 | else |
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| 133 | { |
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| 134 | fprintf(stderr,"Unexpected startcode %08x in system layer\n",code); |
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| 135 | exit(1); |
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| 136 | } |
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| 137 | break; |
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| 138 | } |
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| 139 | } |
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| 140 | } |
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| 141 | |||
| 142 | |||
| 143 | |||
| 144 | void Flush_Buffer32() |
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| 145 | { |
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| 146 | int Incnt; |
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| 147 | |||
| 148 | ld->Bfr = 0; |
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| 149 | |||
| 150 | Incnt = ld->Incnt; |
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| 151 | Incnt -= 32; |
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| 152 | |||
| 153 | if (System_Stream_Flag && (ld->Rdptr >= ld->Rdmax-4)) |
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| 154 | { |
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| 155 | while (Incnt <= 24) |
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| 156 | { |
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| 157 | if (ld->Rdptr >= ld->Rdmax) |
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| 158 | Next_Packet(); |
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| 159 | ld->Bfr |= Get_Byte() << (24 - Incnt); |
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| 160 | Incnt += 8; |
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| 161 | } |
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| 162 | } |
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| 163 | else |
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| 164 | { |
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| 165 | while (Incnt <= 24) |
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| 166 | { |
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| 167 | if (ld->Rdptr >= ld->Rdbfr+2048) |
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| 168 | Fill_Buffer(); |
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| 169 | ld->Bfr |= *ld->Rdptr++ << (24 - Incnt); |
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| 170 | Incnt += 8; |
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| 171 | } |
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| 172 | } |
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| 173 | ld->Incnt = Incnt; |
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| 174 | |||
| 175 | #ifdef VERIFY |
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| 176 | ld->Bitcnt += 32; |
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| 177 | #endif /* VERIFY */ |
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| 178 | } |
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| 179 | |||
| 180 | |||
| 181 | unsigned int Get_Bits32() |
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| 182 | { |
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| 183 | unsigned int l; |
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| 184 | |||
| 185 | l = Show_Bits(32); |
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| 186 | Flush_Buffer32(); |
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| 187 | |||
| 188 | return l; |
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| 189 | } |
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| 190 | |||
| 191 | |||
| 192 | int Get_Long() |
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| 193 | { |
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| 194 | int i; |
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| 195 | |||
| 196 | i = Get_Word(); |
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| 197 | return (i<<16) | Get_Word(); |
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| 198 | } |
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| 199 | |||
| 200 |