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  1. /*
  2. * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
  3. * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
  4. *
  5. * This file is part of FFmpeg.
  6. *
  7. * FFmpeg is free software; you can redistribute it and/or
  8. * modify it under the terms of the GNU Lesser General Public
  9. * License as published by the Free Software Foundation; either
  10. * version 2.1 of the License, or (at your option) any later version.
  11. *
  12. * FFmpeg is distributed in the hope that it will be useful,
  13. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15. * Lesser General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU Lesser General Public
  18. * License along with FFmpeg; if not, write to the Free Software
  19. * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20. */
  21. /**
  22. * @file
  23. * Context Adaptive Binary Arithmetic Coder.
  24. */
  25. #include <string.h>
  26. #include "libavutil/common.h"
  27. #include "libavutil/timer.h"
  28. #include "cabac.h"
  29. #include "cabac_functions.h"
  30. DECLARE_ASM_ALIGNED(1, const uint8_t, ff_h264_cabac_tables)[512 + 4*2*64 + 4*64 + 63] = {
  31. 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
  32. 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
  33. 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
  34. 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
  35. 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
  36. 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
  37. 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
  38. 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
  39. 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  40. 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  41. 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  42. 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  43. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  44. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  45. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  46. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  47. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  48. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  49. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  50. 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  51. // LPS range
  52. -128, -128, -128, -128, -128, -128, 123, 123,
  53. 116, 116, 111, 111, 105, 105, 100, 100,
  54. 95, 95, 90, 90, 85, 85, 81, 81,
  55. 77, 77, 73, 73, 69, 69, 66, 66,
  56. 62, 62, 59, 59, 56, 56, 53, 53,
  57. 51, 51, 48, 48, 46, 46, 43, 43,
  58. 41, 41, 39, 39, 37, 37, 35, 35,
  59. 33, 33, 32, 32, 30, 30, 29, 29,
  60. 27, 27, 26, 26, 24, 24, 23, 23,
  61. 22, 22, 21, 21, 20, 20, 19, 19,
  62. 18, 18, 17, 17, 16, 16, 15, 15,
  63. 14, 14, 14, 14, 13, 13, 12, 12,
  64. 12, 12, 11, 11, 11, 11, 10, 10,
  65. 10, 10, 9, 9, 9, 9, 8, 8,
  66. 8, 8, 7, 7, 7, 7, 7, 7,
  67. 6, 6, 6, 6, 6, 6, 2, 2,
  68. -80, -80, -89, -89, -98, -98, -106, -106,
  69. -114, -114, -121, -121, -128, -128, 122, 122,
  70. 116, 116, 110, 110, 104, 104, 99, 99,
  71. 94, 94, 89, 89, 85, 85, 80, 80,
  72. 76, 76, 72, 72, 69, 69, 65, 65,
  73. 62, 62, 59, 59, 56, 56, 53, 53,
  74. 50, 50, 48, 48, 45, 45, 43, 43,
  75. 41, 41, 39, 39, 37, 37, 35, 35,
  76. 33, 33, 31, 31, 30, 30, 28, 28,
  77. 27, 27, 26, 26, 24, 24, 23, 23,
  78. 22, 22, 21, 21, 20, 20, 19, 19,
  79. 18, 18, 17, 17, 16, 16, 15, 15,
  80. 14, 14, 14, 14, 13, 13, 12, 12,
  81. 12, 12, 11, 11, 11, 11, 10, 10,
  82. 9, 9, 9, 9, 9, 9, 8, 8,
  83. 8, 8, 7, 7, 7, 7, 2, 2,
  84. -48, -48, -59, -59, -69, -69, -78, -78,
  85. -87, -87, -96, -96, -104, -104, -112, -112,
  86. -119, -119, -126, -126, 123, 123, 117, 117,
  87. 111, 111, 105, 105, 100, 100, 95, 95,
  88. 90, 90, 86, 86, 81, 81, 77, 77,
  89. 73, 73, 69, 69, 66, 66, 63, 63,
  90. 59, 59, 56, 56, 54, 54, 51, 51,
  91. 48, 48, 46, 46, 43, 43, 41, 41,
  92. 39, 39, 37, 37, 35, 35, 33, 33,
  93. 32, 32, 30, 30, 29, 29, 27, 27,
  94. 26, 26, 25, 25, 23, 23, 22, 22,
  95. 21, 21, 20, 20, 19, 19, 18, 18,
  96. 17, 17, 16, 16, 15, 15, 15, 15,
  97. 14, 14, 13, 13, 12, 12, 12, 12,
  98. 11, 11, 11, 11, 10, 10, 10, 10,
  99. 9, 9, 9, 9, 8, 8, 2, 2,
  100. -16, -16, -29, -29, -40, -40, -51, -51,
  101. -61, -61, -71, -71, -81, -81, -90, -90,
  102. -98, -98, -106, -106, -114, -114, -121, -121,
  103. -128, -128, 122, 122, 116, 116, 110, 110,
  104. 104, 104, 99, 99, 94, 94, 89, 89,
  105. 85, 85, 80, 80, 76, 76, 72, 72,
  106. 69, 69, 65, 65, 62, 62, 59, 59,
  107. 56, 56, 53, 53, 50, 50, 48, 48,
  108. 45, 45, 43, 43, 41, 41, 39, 39,
  109. 37, 37, 35, 35, 33, 33, 31, 31,
  110. 30, 30, 28, 28, 27, 27, 25, 25,
  111. 24, 24, 23, 23, 22, 22, 21, 21,
  112. 20, 20, 19, 19, 18, 18, 17, 17,
  113. 16, 16, 15, 15, 14, 14, 14, 14,
  114. 13, 13, 12, 12, 12, 12, 11, 11,
  115. 11, 11, 10, 10, 9, 9, 2, 2,
  116. // mlps state
  117. 127, 126, 77, 76, 77, 76, 75, 74,
  118. 75, 74, 75, 74, 73, 72, 73, 72,
  119. 73, 72, 71, 70, 71, 70, 71, 70,
  120. 69, 68, 69, 68, 67, 66, 67, 66,
  121. 67, 66, 65, 64, 65, 64, 63, 62,
  122. 61, 60, 61, 60, 61, 60, 59, 58,
  123. 59, 58, 57, 56, 55, 54, 55, 54,
  124. 53, 52, 53, 52, 51, 50, 49, 48,
  125. 49, 48, 47, 46, 45, 44, 45, 44,
  126. 43, 42, 43, 42, 39, 38, 39, 38,
  127. 37, 36, 37, 36, 33, 32, 33, 32,
  128. 31, 30, 31, 30, 27, 26, 27, 26,
  129. 25, 24, 23, 22, 23, 22, 19, 18,
  130. 19, 18, 17, 16, 15, 14, 13, 12,
  131. 11, 10, 9, 8, 9, 8, 5, 4,
  132. 5, 4, 3, 2, 1, 0, 0, 1,
  133. 2, 3, 4, 5, 6, 7, 8, 9,
  134. 10, 11, 12, 13, 14, 15, 16, 17,
  135. 18, 19, 20, 21, 22, 23, 24, 25,
  136. 26, 27, 28, 29, 30, 31, 32, 33,
  137. 34, 35, 36, 37, 38, 39, 40, 41,
  138. 42, 43, 44, 45, 46, 47, 48, 49,
  139. 50, 51, 52, 53, 54, 55, 56, 57,
  140. 58, 59, 60, 61, 62, 63, 64, 65,
  141. 66, 67, 68, 69, 70, 71, 72, 73,
  142. 74, 75, 76, 77, 78, 79, 80, 81,
  143. 82, 83, 84, 85, 86, 87, 88, 89,
  144. 90, 91, 92, 93, 94, 95, 96, 97,
  145. 98, 99, 100, 101, 102, 103, 104, 105,
  146. 106, 107, 108, 109, 110, 111, 112, 113,
  147. 114, 115, 116, 117, 118, 119, 120, 121,
  148. 122, 123, 124, 125, 124, 125, 126, 127,
  149. // last_coeff_flag_offset_8x8
  150. 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  151. 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  152. 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
  153. 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
  154. };
  155. /**
  156. * @param buf_size size of buf in bits
  157. */
  158. void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){
  159. init_put_bits(&c->pb, buf, buf_size);
  160. c->low= 0;
  161. c->range= 0x1FE;
  162. c->outstanding_count= 0;
  163. c->pb.bit_left++; //avoids firstBitFlag
  164. }
  165. /**
  166. *
  167. * @param buf_size size of buf in bits
  168. */
  169. int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
  170. c->bytestream_start=
  171. c->bytestream= buf;
  172. c->bytestream_end= buf + buf_size;
  173. #if CABAC_BITS == 16
  174. c->low = (*c->bytestream++)<<18;
  175. c->low+= (*c->bytestream++)<<10;
  176. // Keep our fetches on a 2-byte boundary as this should avoid ever having to
  177. // do unaligned loads if the compiler (or asm) optimises the double byte
  178. // load into a single instruction
  179. if(((uintptr_t)c->bytestream & 1) == 0) {
  180. c->low += (1 << 9);
  181. }
  182. else {
  183. c->low += ((*c->bytestream++) << 2) + 2;
  184. }
  185. #else
  186. c->low = (*c->bytestream++)<<10;
  187. c->low+= ((*c->bytestream++)<<2) + 2;
  188. #endif
  189. c->range= 0x1FE;
  190. if ((c->range<<(CABAC_BITS+1)) < c->low)
  191. return AVERROR_INVALIDDATA;
  192. return 0;
  193. }