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FFmpeg/libavcodec/liba52/bit_allocate.c

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  1. /*

  2.  * bit_allocate.c

  3.  * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>

  4.  * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>

  5.  *

  6.  * This file is part of a52dec, a free ATSC A-52 stream decoder.

  7.  * See http://liba52.sourceforge.net/ for updates.

  8.  *

  9.  * a52dec is free software; you can redistribute it and/or modify

  10.  * it under the terms of the GNU General Public License as published by

  11.  * the Free Software Foundation; either version 2 of the License, or

  12.  * (at your option) any later version.

  13.  *

  14.  * a52dec is distributed in the hope that it will be useful,

  15.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  16.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  17.  * GNU General Public License for more details.

  18.  *

  19.  * You should have received a copy of the GNU General Public License

  20.  * along with this program; if not, write to the Free Software

  21.  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  22.  */

  23. #include "a52.h"

  24. #include "a52_internal.h"

  25. 

  26. static int hthtab[3][50] = {

  27.     {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,

  28.      0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,

  29.      0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,

  30.      0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,

  31.      0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},

  32.     {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,

  33.      0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,

  34.      0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,

  35.      0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,

  36.      0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},

  37.     {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,

  38.      0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,

  39.      0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,

  40.      0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,

  41.      0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}

  42. };

  43. 

  44. static int8_t baptab[305] = {

  45.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

  46.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

  47.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

  48.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

  49.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

  50.     16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,	/* 93 padding elems */

  51. 

  52.     16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,

  53.     14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10,  9,  9,  9,

  54.      9,  8,  8,  8,  8,  7,  7,  7,  7,  6,  6,  6,  6,  5,  5,  5,

  55.      5,  4,  4, -3, -3,  3,  3,  3, -2, -2, -1, -1, -1, -1, -1,  0,

  56. 

  57.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  58.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  59.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  60.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  61.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  62.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  63.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  64.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  65.      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

  66.      0,  0,  0,  0					/* 148 padding elems */

  67. };

  68. 

  69. static int bndtab[30] = {21, 22,  23,  24,  25,  26,  27,  28,  31,  34,

  70. 			 37, 40,  43,  46,  49,  55,  61,  67,  73,  79,

  71. 			 85, 97, 109, 121, 133, 157, 181, 205, 229, 253};

  72. 

  73. static int8_t latab[256] = {

  74.     -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,

  75.     -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,

  76.     -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,

  77.     -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,

  78.     -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,

  79.     -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,

  80.     -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,

  81.     -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,

  82.     -10, -10, -10, -10, -10,  -9,  -9,  -9,  -9,  -9,  -8,  -8,

  83.      -8,  -8,  -8,  -8,  -7,  -7,  -7,  -7,  -7,  -7,  -6,  -6,

  84.      -6,  -6,  -6,  -6,  -6,  -6,  -5,  -5,  -5,  -5,  -5,  -5,

  85.      -5,  -5,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,

  86.      -4,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,

  87.      -3,  -3,  -3,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,

  88.      -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -1,  -1,

  89.      -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,

  90.      -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,

  91.      -1,  -1,  -1,  -1,  -1,  -1,   0,   0,   0,   0,   0,   0,

  92.       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

  93.       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

  94.       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

  95.       0,   0,   0,   0

  96. };

  97. 

  98. #define UPDATE_LEAK() 		\

  99. do {				\

  100.     fastleak += fdecay;		\

  101.     if (fastleak > psd + fgain)	\

  102. 	fastleak = psd + fgain;	\

  103.     slowleak += sdecay;		\

  104.     if (slowleak > psd + sgain)	\

  105. 	slowleak = psd + sgain;	\

  106. } while (0)

  107. 

  108. #define COMPUTE_MASK()				\

  109. do {						\

  110.     if (psd > dbknee)				\

  111. 	mask -= (psd - dbknee) >> 2;		\

  112.     if (mask > hth [i >> halfrate])		\

  113. 	mask = hth [i >> halfrate];		\

  114.     mask -= snroffset + 128 * deltba[i];	\

  115.     mask = (mask > 0) ? 0 : ((-mask) >> 5);	\

  116.     mask -= floor;				\

  117. } while (0)

  118. 

  119. void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,

  120. 		       int start, int end, int fastleak, int slowleak,

  121. 		       expbap_t * expbap)

  122. {

  123.     static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};

  124.     static int dbpbtab[4]  = {0xc00, 0x500, 0x300, 0x100};

  125.     static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,

  126. 			      0xa10, 0xa90, 0xb10, 0x1400};

  127. 

  128.     int i, j;

  129.     uint8_t * exp;

  130.     int8_t * bap;

  131.     int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;

  132.     int psd, mask;

  133.     int8_t * deltba;

  134.     int * hth;

  135.     int halfrate;

  136. 

  137.     halfrate = state->halfrate;

  138.     fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate;	/* fdcycod */

  139.     fgain = 128 + 128 * (ba->bai & 7);				/* fgaincod */

  140.     sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate;		/* sdcycod */

  141.     sgain = slowgain[(state->bai >> 5) & 3];			/* sgaincod */

  142.     dbknee = dbpbtab[(state->bai >> 3) & 3];			/* dbpbcod */

  143.     hth = hthtab[state->fscod];

  144.     /*

  145.      * if there is no delta bit allocation, make deltba point to an area

  146.      * known to contain zeroes. baptab+156 here.

  147.      */

  148.     deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;

  149.     floor = floortab[state->bai & 7];				/* floorcod */

  150.     snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;

  151.     floor >>= 5;

  152. 

  153.     exp = expbap->exp;

  154.     bap = expbap->bap;

  155. 

  156.     i = bndstart;

  157.     j = start;

  158.     if (start == 0) {	/* not the coupling channel */

  159. 	int lowcomp;

  160. 

  161. 	lowcomp = 0;

  162. 	j = end - 1;

  163. 	do {

  164. 	    if (i < j) {

  165. 		if (exp[i+1] == exp[i] - 2)

  166. 		    lowcomp = 384;

  167. 		else if (lowcomp && (exp[i+1] > exp[i]))

  168. 		    lowcomp -= 64;

  169. 	    }

  170. 	    psd = 128 * exp[i];

  171. 	    mask = psd + fgain + lowcomp;

  172. 	    COMPUTE_MASK ();

  173. 	    bap[i] = (baptab+156)[mask + 4 * exp[i]];

  174. 	    i++;

  175. 	} while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));

  176. 	fastleak = psd + fgain;

  177. 	slowleak = psd + sgain;

  178. 

  179. 	while (i < 7) {

  180. 	    if (i < j) {

  181. 		if (exp[i+1] == exp[i] - 2)

  182. 		    lowcomp = 384;

  183. 		else if (lowcomp && (exp[i+1] > exp[i]))

  184. 		    lowcomp -= 64;

  185. 	    }

  186. 	    psd = 128 * exp[i];

  187. 	    UPDATE_LEAK ();

  188. 	    mask = ((fastleak + lowcomp < slowleak) ?

  189. 		    fastleak + lowcomp : slowleak);

  190. 	    COMPUTE_MASK ();

  191. 	    bap[i] = (baptab+156)[mask + 4 * exp[i]];

  192. 	    i++;

  193. 	}

  194. 

  195. 	if (end == 7)	/* lfe channel */

  196. 	    return;

  197. 

  198. 	do {

  199. 	    if (exp[i+1] == exp[i] - 2)

  200. 		lowcomp = 320;

  201. 	    else if (lowcomp && (exp[i+1] > exp[i]))

  202. 		lowcomp -= 64;

  203. 	    psd = 128 * exp[i];

  204. 	    UPDATE_LEAK ();

  205. 	    mask = ((fastleak + lowcomp < slowleak) ?

  206. 		    fastleak + lowcomp : slowleak);

  207. 	    COMPUTE_MASK ();

  208. 	    bap[i] = (baptab+156)[mask + 4 * exp[i]];

  209. 	    i++;

  210. 	} while (i < 20);

  211. 

  212. 	while (lowcomp > 128) {		/* two iterations maximum */

  213. 	    lowcomp -= 128;

  214. 	    psd = 128 * exp[i];

  215. 	    UPDATE_LEAK ();

  216. 	    mask = ((fastleak + lowcomp < slowleak) ?

  217. 		    fastleak + lowcomp : slowleak);

  218. 	    COMPUTE_MASK ();

  219. 	    bap[i] = (baptab+156)[mask + 4 * exp[i]];

  220. 	    i++;

  221. 	}

  222. 	j = i;

  223.     }

  224. 

  225.     do {

  226. 	int startband, endband;

  227. 

  228. 	startband = j;

  229. 	endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;

  230. 	psd = 128 * exp[j++];

  231. 	while (j < endband) {

  232. 	    int next, delta;

  233. 

  234. 	    next = 128 * exp[j++];

  235. 	    delta = next - psd;

  236. 	    switch (delta >> 9) {

  237. 	    case -6: case -5: case -4: case -3: case -2:

  238. 		psd = next;

  239. 		break;

  240. 	    case -1:

  241. 		psd = next + latab[(-delta) >> 1];

  242. 		break;

  243. 	    case 0:

  244. 		psd += latab[delta >> 1];

  245. 		break;

  246. 	    }

  247. 	}

  248. 	/* minpsd = -289 */

  249. 	UPDATE_LEAK ();

  250. 	mask = (fastleak < slowleak) ? fastleak : slowleak;

  251. 	COMPUTE_MASK ();

  252. 	i++;

  253. 	j = startband;

  254. 	do {

  255. 	    /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */

  256. 	    /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */

  257. 	    bap[j] = (baptab+156)[mask + 4 * exp[j]];

  258. 	} while (++j < endband);

  259.     } while (j < end);

  260. }