1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 20 Pathname: get_tns.c 21 22 Date: 10/25/2000 23 24 ------------------------------------------------------------------------------ 25 REVISION HISTORY 26 27 Description: Modified from original shareware code 28 29 Description: Modified to pass variables by reference to eliminate use 30 of global variables. 31 32 Description: Brought code in-line with PV standards. Some minor 33 optimizations (count-down for loops, etc.) were made. 34 35 Description: Made cosmetic changes as suggested during review. Also, 36 changed calculation of s_mask and n_mask from table-based to being 37 calculated based on res_index. Also, the flag coef_res was changed 38 from having a range of [3,4] to having a range of [0,1], which corresponds 39 exactly with the true value that is passed via the bitstream. 40 41 Description: Modified to use more efficient TNS memory structure. 42 43 Description: Updated to reflect more efficient usage of memory by the TNS 44 filters. 45 46 Description: Updated the SW template to include the full pathname to the 47 source file and a slightly modified copyright header. 48 49 Description: Moved pInputStream to be the 2nd parameter, for a slight 50 optimization on some platforms. 51 52 Description: Moved pSfbTop outside of the loops, since its value does 53 not change. 54 55 Description: Replace some instances of getbits to get1bits 56 when only 1 bit is read. 57 58 Who: Date: 59 Description: 60 61 ------------------------------------------------------------------------------ 62 INPUT AND OUTPUT DEFINITIONS 63 64 Inputs: 65 FrameInfo *pFrameInfo 66 Pointer to structure that holds information about each block. 67 (long block flag, 68 number of subblocks, 69 scalefactor bands per subblock, etc.) 70 71 BITS *pInputStream 72 Pointer to a BITS structure that is 73 passed on to function getbits to pull information from the bitstream. 74 75 TNS_Frame_info *pTnsFrameInfo 76 Pointer to filter data structure - to be populated by this function. 77 78 Local Stores/Buffers/Pointers Needed: 79 None 80 81 Global Stores/Buffers/Pointers Needed: 82 None 83 84 Outputs: 85 None 86 87 Pointers and Buffers Modified: 88 TNS_frame_info *pTnsFrameInfo 89 90 pTnsFrameInfo->n_filt = Number of tns filters to be applied to the data. 91 92 pTnsFrameInfo->filt[]->order = The order of each individual TNS filter. 93 94 pTnsFrameInfo->filt[]->coef_res = The resolution of the filter coefficients 95 96 pTnsFrameInfo->filt[]->start_band = start of spectral band 97 98 pTnsFrameInfo->filt[]->stop_band = end of spectral band 99 100 pTnsFrameInfo->filt[]->coef[] = Each filter's coefficients are filled with 101 data read from the input bitstream. 102 103 pTnsFrameInfo->filt[]->direction = A flag is set for each TNS filter. 104 105 If the direction flag (on the bitstream) = 0, then the filter 106 is applied to the block of spectral data in normal (upward) fashion. 107 108 If the direction flag (on the bitstream) = 1, then the filter 109 is applied in a reverse (downward) fashion. 110 (Starting with the last element in the block of data.) 111 112 The value stored in filt[]->direction maps the values [0,1] to [1,-1] for 113 a more intuitive storage of this flag's meaning. 114 115 Local Stores Modified: 116 117 Global Stores Modified: 118 119 120 ------------------------------------------------------------------------------ 121 FUNCTION DESCRIPTION 122 123 This function reads the TNS filter information from the bitstream, and stores 124 the filter order, LPC coefficients, and the number of TNS filters to 125 be applied in the structure TNS_frame_info. 126 127 ------------------------------------------------------------------------------ 128 REQUIREMENTS 129 130 This code should match the ISO code in functionality, with the exception 131 that coef_res has range of [0,1] (PV code) instead of [3,4] (ISO code) 132 133 coef_res is only used by tns_decode_coef. 134 135 ------------------------------------------------------------------------------ 136 REFERENCES 137 (1) ISO/IEC 14496-3:1999(E) 138 Part 3 139 Subpart 4.6.8 (Temporal Noise Shaping) 140 141 (2) MPEG-2 NBC Audio Decoder 142 "This software module was originally developed by AT&T, Dolby 143 Laboratories, Fraunhofer Gesellschaft IIS in the course of development 144 of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and 145 3. This software module is an implementation of a part of one or more 146 MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 147 Audio standard. ISO/IEC gives users of the MPEG-2 NBC/MPEG-4 Audio 148 standards free license to this software module or modifications thereof 149 for use in hardware or software products claiming conformance to the 150 MPEG-2 NBC/MPEG-4 Audio standards. Those intending to use this software 151 module in hardware or software products are advised that this use may 152 infringe existing patents. The original developer of this software 153 module and his/her company, the subsequent editors and their companies, 154 and ISO/IEC have no liability for use of this software module or 155 modifications thereof in an implementation. Copyright is not released 156 for non MPEG-2 NBC/MPEG-4 Audio conforming products.The original 157 developer retains full right to use the code for his/her own purpose, 158 assign or donate the code to a third party and to inhibit third party 159 from using the code for non MPEG-2 NBC/MPEG-4 Audio conforming products. 160 This copyright notice must be included in all copies or derivative 161 works." 162 Copyright(c)1996. 163 164 ------------------------------------------------------------------------------ 165 PSEUDO-CODE 166 167 168 ------------------------------------------------------------------------------ 169 RESOURCES USED 170 When the code is written for a specific target processor 171 the resources used should be documented below. 172 173 STACK USAGE: [stack count for this module] + [variable to represent 174 stack usage for each subroutine called] 175 176 where: [stack usage variable] = stack usage for [subroutine 177 name] (see [filename].ext) 178 179 DATA MEMORY USED: x words 180 181 PROGRAM MEMORY USED: x words 182 183 CLOCK CYCLES: [cycle count equation for this module] + [variable 184 used to represent cycle count for each subroutine 185 called] 186 187 where: [cycle count variable] = cycle count for [subroutine 188 name] (see [filename].ext) 189 190 ----------------------------------------------------------------------------*/ 191 /*---------------------------------------------------------------------------- 192 ; INCLUDES 193 ----------------------------------------------------------------------------*/ 194 #include "pv_audio_type_defs.h" 195 #include "get_tns.h" 196 #include "s_mc_info.h" 197 #include "s_frameinfo.h" 198 #include "s_tnsfilt.h" 199 #include "s_tns_frame_info.h" 200 #include "s_bits.h" 201 #include "ibstream.h" 202 #include "e_window_sequence.h" 203 #include "e_progconfigconst.h" 204 205 #include "tns_decode_coef.h" 206 207 208 /*---------------------------------------------------------------------------- 209 ; MACROS 210 ; Define module specific macros here 211 ----------------------------------------------------------------------------*/ 212 #define SCALE_FACTOR_BAND_OFFSET(x) ( ((x) > 0) ? pSFB_top[(x)-1] : 0 ) 213 #define MINIMUM(x,y) ( ((x) < (y)) ? (x) : (y) ) 214 215 /*---------------------------------------------------------------------------- 216 ; DEFINES 217 ; Include all pre-processor statements here. Include conditional 218 ; compile variables also. 219 ----------------------------------------------------------------------------*/ 220 /*---------------------------------------------------------------------------- 221 ; LOCAL FUNCTION DEFINITIONS 222 ; Function Prototype declaration 223 ----------------------------------------------------------------------------*/ 224 /*---------------------------------------------------------------------------- 225 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 226 ; Variable declaration - defined here and used outside this module 227 ----------------------------------------------------------------------------*/ 228 /* 229 * The entries in the ensuing tables provide the maximum permissable 230 * number of scalefactor bands for each TNS filter. This value is effected 231 * by the sampling rate, and window type. 232 */ 233 234 const Int tns_max_bands_tbl_long_wndw[(1<<LEN_SAMP_IDX)] = 235 {31, /* 96000 Hz */ 236 31, /* 88200 Hz */ 237 34, /* 64000 Hz */ 238 40, /* 48000 Hz */ 239 42, /* 44100 Hz */ 240 51, /* 32000 Hz */ 241 46, /* 24000 Hz */ 242 46, /* 22050 Hz */ 243 42, /* 16000 Hz */ 244 42, /* 12000 Hz */ 245 42, /* 11025 Hz */ 246 39, /* 8000 Hz */ 247 0, 248 0, 249 0, 250 0 251 }; 252 253 const Int tns_max_bands_tbl_short_wndw[(1<<LEN_SAMP_IDX)] = 254 {9, /* 96000 Hz */ 255 9, /* 88200 Hz */ 256 10, /* 64000 Hz */ 257 14, /* 48000 Hz */ 258 14, /* 44100 Hz */ 259 14, /* 32000 Hz */ 260 14, /* 24000 Hz */ 261 14, /* 22050 Hz */ 262 14, /* 16000 Hz */ 263 14, /* 12000 Hz */ 264 14, /* 11025 Hz */ 265 14, /* 8000 Hz */ 266 0, 267 0, 268 0, 269 0 270 }; 271 272 /* 273 * For completeness, here are the table entries for object types that make 274 * use of PQF filter bank. We do not currently support this; these are 275 * given here only to ease future implementation. 276 * 277 * const Int tns_max_bands_tbl_long_wndw_PQF[(1<<LEN_SAMP_IDX)] = 278 * {28, ; 96000 279 * 28, ; 88200 280 * 27, ; 64000 281 * 26, ; 48000 282 * 26, ; 44100 283 * 26, ; 32000 284 * 29, ; 24000 285 * 29, ; 22050 286 * 23, ; 16000 287 * 23, ; 12000 288 * 23, ; 11025 289 * 19, ; 8000 290 * 0, 291 * 0, 292 * 0, 293 * 0}; 294 * 295 * const Int tns_max_bands_tbl_short_wndw_PQF[(1<<LEN_SAMP_IDX)] = 296 * {7, ; 96000 297 * 7, ; 88200 298 * 7, ; 64000 299 * 6, ; 48000 300 * 6, ; 44100 301 * 6, ; 32000 302 * 7, ; 24000 303 * 7, ; 22050 304 * 8, ; 16000 305 * 8, ; 12000 306 * 8, ; 11025 307 * 7, ; 8000 308 * 0, 309 * 0, 310 * 0, 311 * 0}; 312 */ 313 314 /*---------------------------------------------------------------------------- 315 ; EXTERNAL FUNCTION REFERENCES 316 ; Declare functions defined elsewhere and referenced in this module 317 ----------------------------------------------------------------------------*/ 318 /*---------------------------------------------------------------------------- 319 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 320 ; Declare variables used in this module but defined elsewhere 321 ----------------------------------------------------------------------------*/ 322 /*---------------------------------------------------------------------------- 323 ; FUNCTION CODE 324 ----------------------------------------------------------------------------*/ 325 326 327 void get_tns( 328 const Int max_bands, 329 BITS * const pInputStream, 330 const WINDOW_SEQUENCE wnd_seq, 331 const FrameInfo * const pFrameInfo, 332 const MC_Info * const pMC_Info, 333 TNS_frame_info * const pTnsFrameInfo, 334 Int32 scratchTnsDecCoefMem[]) 335 { 336 337 const Int16 * const pSFB_top = pFrameInfo->win_sfb_top[0]; 338 339 Int f; 340 Int t; 341 Int win; 342 UInt tempInt; 343 344 Int num_filt_bits; 345 Int num_order_bits; 346 Int num_start_band_bits; 347 348 Int top; 349 Int res; 350 Int res_index; 351 Int compress; 352 353 Int sfb_per_win; 354 355 Int32 *pLpcCoef; 356 Int32 *pStartLpcCoef; 357 Int s_mask; 358 Int n_mask; 359 360 Int tns_bands; 361 UInt max_order; 362 Int coef_res; 363 364 365 TNSfilt *pFilt; 366 367 if (wnd_seq != EIGHT_SHORT_SEQUENCE) 368 { 369 num_filt_bits = 2; 370 num_order_bits = 5; 371 num_start_band_bits = 6; 372 373 tns_bands = tns_max_bands_tbl_long_wndw[pMC_Info->sampling_rate_idx]; 374 375 /* 376 * Definition from 14496-3:1999 doc. Our first encoder follows this rule, 377 * later encoders don't 378 */ 379 380 if (pMC_Info->sampling_rate_idx > 4) /* if (sampling_rate <= 32000 */ 381 { 382 max_order = 20; 383 } 384 else 385 { 386 max_order = 12; 387 } 388 } 389 else 390 { 391 num_filt_bits = 1; 392 num_order_bits = 3; 393 num_start_band_bits = 4; 394 395 tns_bands = tns_max_bands_tbl_short_wndw[pMC_Info->sampling_rate_idx]; 396 397 max_order = 7; 398 } 399 400 /* 401 * After this branch, tns_bands will be equal to the minimum of 402 * the passed in variable, nbands, and the result from the 403 * tns_max_bands_tbl 404 */ 405 406 if (max_bands < tns_bands) 407 { 408 tns_bands = max_bands; 409 } 410 411 sfb_per_win = pFrameInfo->sfb_per_win[0]; 412 413 win = 0; 414 415 pLpcCoef = pTnsFrameInfo->lpc_coef; 416 417 pFilt = pTnsFrameInfo->filt; 418 419 do 420 { 421 tempInt = get9_n_lessbits(num_filt_bits, 422 pInputStream); 423 424 pTnsFrameInfo->n_filt[win] = tempInt; 425 426 if (tempInt != 0) 427 { 428 /* 429 * coef_res = [0, 1] 430 * Switch between a resolution of 3 and 4 bits respectively 431 * 432 * if coef_res = 0, the coefficients have a range of 433 * 434 * -4 -3 -2 -1 0 1 2 3 435 * 436 * if coef_res = 1, the coefficients have a range of 437 * 438 * -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 439 * 440 * The arrays in ./src/tns_tab.c are completely based on 441 * the value of coef_res. 442 */ 443 res = get1bits( 444 pInputStream); 445 446 /* res is post-incremented for correct calculation of res_index */ 447 coef_res = res++; 448 449 top = sfb_per_win; 450 451 for (f = pTnsFrameInfo->n_filt[win]; f > 0; f--) 452 { 453 tempInt = MINIMUM(top, tns_bands); 454 455 pFilt->stop_coef = SCALE_FACTOR_BAND_OFFSET(tempInt); 456 457 pFilt->stop_band = tempInt; 458 459 top -= get9_n_lessbits(num_start_band_bits, 460 pInputStream); 461 462 tempInt = MINIMUM(top, tns_bands); 463 464 pFilt->start_coef = SCALE_FACTOR_BAND_OFFSET(tempInt); 465 466 pFilt->start_band = tempInt; 467 468 tempInt = get9_n_lessbits(num_order_bits, 469 pInputStream); 470 471 pFilt->order = tempInt; 472 473 if (tempInt != 0) 474 { 475 if (tempInt > max_order) 476 { 477 pFilt->order = max_order; 478 } 479 480 /* 481 * This maps the bitstream's [0,1] to 482 * pFilt->direction = [1,-1] 483 */ 484 485 tempInt = get1bits(pInputStream); 486 487 pFilt->direction = (-(Int)tempInt) | 0x1; 488 489 /* 490 * compress = [0,1] 491 * If compress is true, the MSB has 492 * been omitted from transmission (Ref. 1) 493 * 494 * For coef_res = 0, this limits the range of 495 * transmitted coefficients to... 496 * 497 * -2 -1 0 1 498 * 499 * For coef_res = 1, the coefficients have 500 * a range of... 501 * 502 * -4 -3 -2 -1 0 1 2 3 503 */ 504 compress = get1bits(pInputStream); 505 506 /* 507 * res has a range of [1,2] 508 * compress has a range of [0,1] 509 * So (res - compress) has range [0,2]; 510 */ 511 res_index = res - compress; 512 513 s_mask = 2 << res_index; 514 515 /* 516 * If res_index = 0, grab 2 bits of data 517 * If res_index = 1, grab 3 bits of data 518 * If res_index = 2, grab 4 bits of data 519 */ 520 res_index += 2; 521 522 pStartLpcCoef = pLpcCoef; 523 524 for (t = pFilt->order; t > 0; t--) 525 { 526 /* 527 * These are the encoded coefficients, which will 528 * later be decoded into LPC coefficients by 529 * the function tns_decode_coef() 530 */ 531 tempInt = get9_n_lessbits(res_index, 532 pInputStream); 533 534 n_mask = -((Int)tempInt & s_mask); 535 536 /* 537 * n_mask is used to sign_extend the 538 * value, if it is negative. 539 * 540 */ 541 *(pLpcCoef++) = tempInt | n_mask; 542 } 543 544 /* Decode the TNS coefficients */ 545 546 tempInt = pFilt->stop_coef - pFilt->start_coef; 547 548 if (tempInt > 0) 549 { 550 pFilt->q_lpc = 551 tns_decode_coef( 552 pFilt->order, 553 coef_res, 554 pStartLpcCoef, 555 scratchTnsDecCoefMem); 556 } 557 558 } /* if (pTnsFilt->order != 0) */ 559 560 pFilt++; 561 562 } /* END for (f=pTnsInfo->n_filt; f>0; f--, pTnsFilt++) */ 563 564 } /* if (pTnsInfo->n_filt != 0) */ 565 566 win++; 567 568 } 569 while (win < pFrameInfo->num_win); 570 571 return; 572 573 } /* get_tns */ 574
