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1/* ***** BEGIN LICENSE BLOCK *****
2 * Source last modified: $Id: dequant.c,v 1.2 2005/05/20 18:05:41 jrecker Exp $
3 *
4 * Portions Copyright (c) 1995-2005 RealNetworks, Inc. All Rights Reserved.
5 *
6 * The contents of this file, and the files included with this file,
7 * are subject to the current version of the RealNetworks Public
8 * Source License (the "RPSL") available at
9 * http://www.helixcommunity.org/content/rpsl unless you have licensed
10 * the file under the current version of the RealNetworks Community
11 * Source License (the "RCSL") available at
12 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL
13 * will apply. You may also obtain the license terms directly from
14 * RealNetworks. You may not use this file except in compliance with
15 * the RPSL or, if you have a valid RCSL with RealNetworks applicable
16 * to this file, the RCSL. Please see the applicable RPSL or RCSL for
17 * the rights, obligations and limitations governing use of the
18 * contents of the file.
19 *
20 * This file is part of the Helix DNA Technology. RealNetworks is the
21 * developer of the Original Code and owns the copyrights in the
22 * portions it created.
23 *
24 * This file, and the files included with this file, is distributed
25 * and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY
26 * KIND, EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS
27 * ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES
28 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET
29 * ENJOYMENT OR NON-INFRINGEMENT.
30 *
31 * Technology Compatibility Kit Test Suite(s) Location:
32 * http://www.helixcommunity.org/content/tck
33 *
34 * Contributor(s):
35 *
36 * ***** END LICENSE BLOCK ***** */
37
38/**************************************************************************************
39 * Fixed-point HE-AAC decoder
40 * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
41 * February 2005
42 *
43 * dequant.c - transform coefficient dequantization and short-block deinterleaving
44 **************************************************************************************/
45
46#include "coder.h"
47#include "assembly.h"
48#include <stdio.h>
49
50
51#define SF_OFFSET 100
52
53/* pow(2, i/4.0) for i = [0,1,2,3], format = Q30 */
54static const int pow14[4] = {
55 0x40000000, 0x4c1bf829, 0x5a82799a, 0x6ba27e65
56};
57
58/* pow(2, i/4.0) * pow(j, 4.0/3.0) for i = [0,1,2,3], j = [0,1,2,...,15]
59 * format = Q28 for j = [0-3], Q25 for j = [4-15]
60 */
61static const int pow43_14[4][16] = {
62 {
63 0x00000000, 0x10000000, 0x285145f3, 0x453a5cdb, /* Q28 */
64 0x0cb2ff53, 0x111989d6, 0x15ce31c8, 0x1ac7f203, /* Q25 */
65 0x20000000, 0x257106b9, 0x2b16b4a3, 0x30ed74b4, /* Q25 */
66 0x36f23fa5, 0x3d227bd3, 0x437be656, 0x49fc823c, /* Q25 */
67 },
68 {
69 0x00000000, 0x1306fe0a, 0x2ff221af, 0x52538f52,
70 0x0f1a1bf4, 0x1455ccc2, 0x19ee62a8, 0x1fd92396,
71 0x260dfc14, 0x2c8694d8, 0x333dcb29, 0x3a2f5c7a,
72 0x4157aed5, 0x48b3aaa3, 0x50409f76, 0x57fc3010,
73 },
74 {
75 0x00000000, 0x16a09e66, 0x39047c0f, 0x61e734aa,
76 0x11f59ac4, 0x182ec633, 0x1ed66a45, 0x25dfc55a,
77 0x2d413ccd, 0x34f3462d, 0x3cefc603, 0x4531ab69,
78 0x4db4adf8, 0x56752054, 0x5f6fcfcd, 0x68a1eca1,
79 },
80 {
81 0x00000000, 0x1ae89f99, 0x43ce3e4b, 0x746d57b2,
82 0x155b8109, 0x1cc21cdc, 0x24ac1839, 0x2d0a479e,
83 0x35d13f33, 0x3ef80748, 0x48775c93, 0x524938cd,
84 0x5c68841d, 0x66d0df0a, 0x717e7bfe, 0x7c6e0305,
85 },
86};
87
88/* pow(j, 4.0 / 3.0) for j = [16,17,18,...,63], format = Q23 */
89static const int pow43[48] = {
90 0x1428a2fa, 0x15db1bd6, 0x1796302c, 0x19598d85,
91 0x1b24e8bb, 0x1cf7fcfa, 0x1ed28af2, 0x20b4582a,
92 0x229d2e6e, 0x248cdb55, 0x26832fda, 0x28800000,
93 0x2a832287, 0x2c8c70a8, 0x2e9bc5d8, 0x30b0ff99,
94 0x32cbfd4a, 0x34eca001, 0x3712ca62, 0x393e6088,
95 0x3b6f47e0, 0x3da56717, 0x3fe0a5fc, 0x4220ed72,
96 0x44662758, 0x46b03e7c, 0x48ff1e87, 0x4b52b3f3,
97 0x4daaebfd, 0x5007b497, 0x5268fc62, 0x54ceb29c,
98 0x5738c721, 0x59a72a59, 0x5c19cd35, 0x5e90a129,
99 0x610b9821, 0x638aa47f, 0x660db90f, 0x6894c90b,
100 0x6b1fc80c, 0x6daeaa0d, 0x70416360, 0x72d7e8b0,
101 0x75722ef9, 0x78102b85, 0x7ab1d3ec, 0x7d571e09,
102};
103
104/* sqrt(0.5), format = Q31 */
105#define SQRTHALF 0x5a82799a
106
107/* Minimax polynomial approximation to pow(x, 4/3), over the range
108 * poly43lo: x = [0.5, 0.7071]
109 * poly43hi: x = [0.7071, 1.0]
110 *
111 * Relative error < 1E-7
112 * Coefs are scaled by 4, 2, 1, 0.5, 0.25
113 */
114static const int poly43lo[5] = { 0x29a0bda9, 0xb02e4828, 0x5957aa1b, 0x236c498d, 0xff581859 };
115static const int poly43hi[5] = { 0x10852163, 0xd333f6a4, 0x46e9408b, 0x27c2cef0, 0xfef577b4 };
116
117/* pow2exp[i] = pow(2, i*4/3) exponent */
118static const int pow2exp[8] = { 14, 13, 11, 10, 9, 7, 6, 5 };
119
120/* pow2exp[i] = pow(2, i*4/3) fraction */
121static const int pow2frac[8] = {
122 0x6597fa94, 0x50a28be6, 0x7fffffff, 0x6597fa94,
123 0x50a28be6, 0x7fffffff, 0x6597fa94, 0x50a28be6
124};
125
126/**************************************************************************************
127 * Function: DequantBlock
128 *
129 * Description: dequantize one block of transform coefficients (in-place)
130 *
131 * Inputs: quantized transform coefficients, range = [0, 8191]
132 * number of samples to dequantize
133 * scalefactor for this block of data, range = [0, 256]
134 *
135 * Outputs: dequantized transform coefficients in Q(FBITS_OUT_DQ_OFF)
136 *
137 * Return: guard bit mask (OR of abs value of all dequantized coefs)
138 *
139 * Notes: applies dequant formula y = pow(x, 4.0/3.0) * pow(2, (scale - 100)/4.0)
140 * * pow(2, FBITS_OUT_DQ_OFF)
141 * clips outputs to Q(FBITS_OUT_DQ_OFF)
142 * output has no minimum number of guard bits
143 **************************************************************************************/
144static int DequantBlock(int *inbuf, int nSamps, int scale)
145{
146 int iSamp, scalef, scalei, x, y, gbMask, shift, tab4[4];
147 const int *tab16, *coef;
148
149 if (nSamps <= 0) {
150 return 0;
151 }
152
153 scale -= SF_OFFSET; /* new range = [-100, 156] */
154
155 /* with two's complement numbers, scalei/scalef factorization works for pos and neg values of scale:
156 * [+4...+7] >> 2 = +1, [ 0...+3] >> 2 = 0, [-4...-1] >> 2 = -1, [-8...-5] >> 2 = -2 ...
157 * (-1 & 0x3) = 3, (-2 & 0x3) = 2, (-3 & 0x3) = 1, (0 & 0x3) = 0
158 *
159 * Example: 2^(-5/4) = 2^(-1) * 2^(-1/4) = 2^-2 * 2^(3/4)
160 */
161 tab16 = pow43_14[scale & 0x3];
162 scalef = pow14[scale & 0x3];
163 scalei = (scale >> 2) + FBITS_OUT_DQ_OFF;
164
165 /* cache first 4 values:
166 * tab16[j] = Q28 for j = [0,3]
167 * tab4[x] = x^(4.0/3.0) * 2^(0.25*scale), Q(FBITS_OUT_DQ_OFF)
168 */
169 shift = 28 - scalei;
170 if (shift > 31) {
171 tab4[0] = tab4[1] = tab4[2] = tab4[3] = 0;
172 } else if (shift <= 0) {
173 shift = -shift;
174 if (shift > 31) {
175 shift = 31;
176 }
177 for (x = 0; x < 4; x++) {
178 y = tab16[x];
179 if (y > (0x7fffffff >> shift)) {
180 y = 0x7fffffff; /* clip (rare) */
181 } else {
182 y <<= shift;
183 }
184 tab4[x] = y;
185 }
186 } else {
187 tab4[0] = 0;
188 tab4[1] = tab16[1] >> shift;
189 tab4[2] = tab16[2] >> shift;
190 tab4[3] = tab16[3] >> shift;
191 }
192
193 gbMask = 0;
194 do {
195 iSamp = *inbuf;
196 x = FASTABS(iSamp);
197
198 if (x < 4) {
199 y = tab4[x];
200 } else {
201
202 if (x < 16) {
203 /* result: y = Q25 (tab16 = Q25) */
204 y = tab16[x];
205 shift = 25 - scalei;
206 } else if (x < 64) {
207 /* result: y = Q21 (pow43tab[j] = Q23, scalef = Q30) */
208 y = pow43[x - 16];
209 shift = 21 - scalei;
210 y = MULSHIFT32(y, scalef);
211 } else {
212 /* normalize to [0x40000000, 0x7fffffff]
213 * input x = [64, 8191] = [64, 2^13-1]
214 * ranges:
215 * shift = 7: 64 - 127
216 * shift = 6: 128 - 255
217 * shift = 5: 256 - 511
218 * shift = 4: 512 - 1023
219 * shift = 3: 1024 - 2047
220 * shift = 2: 2048 - 4095
221 * shift = 1: 4096 - 8191
222 */
223 x <<= 17;
224 shift = 0;
225 if (x < 0x08000000) {
226 x <<= 4, shift += 4;
227 }
228 if (x < 0x20000000) {
229 x <<= 2, shift += 2;
230 }
231 if (x < 0x40000000) {
232 x <<= 1, shift += 1;
233 }
234
235 coef = (x < SQRTHALF) ? poly43lo : poly43hi;
236
237 /* polynomial */
238 y = coef[0];
239 y = MULSHIFT32(y, x) + coef[1];
240 y = MULSHIFT32(y, x) + coef[2];
241 y = MULSHIFT32(y, x) + coef[3];
242 y = MULSHIFT32(y, x) + coef[4];
243 y = MULSHIFT32(y, pow2frac[shift]) << 3;
244
245 /* fractional scale
246 * result: y = Q21 (pow43tab[j] = Q23, scalef = Q30)
247 */
248 y = MULSHIFT32(y, scalef); /* now y is Q24 */
249 shift = 24 - scalei - pow2exp[shift];
250 }
251
252 /* integer scale */
253 if (shift <= 0) {
254 shift = -shift;
255 if (shift > 31) {
256 shift = 31;
257 }
258
259 if (y > (0x7fffffff >> shift)) {
260 y = 0x7fffffff; /* clip (rare) */
261 } else {
262 y <<= shift;
263 }
264 } else {
265 if (shift > 31) {
266 shift = 31;
267 }
268 y >>= shift;
269 }
270 }
271
272 /* sign and store (gbMask used to count GB's) */
273 gbMask |= y;
274
275 /* apply sign */
276 iSamp >>= 31;
277 y ^= iSamp;
278 y -= iSamp;
279
280 *inbuf++ = y;
281 } while (--nSamps);
282
283 return gbMask;
284}
285
286/**************************************************************************************
287 * Function: Dequantize
288 *
289 * Description: dequantize all transform coefficients for one channel
290 *
291 * Inputs: valid AACDecInfo struct (including unpacked, quantized coefficients)
292 * index of current channel
293 *
294 * Outputs: dequantized coefficients, including short-block deinterleaving
295 * flags indicating if intensity and/or PNS is active
296 * minimum guard bit count for dequantized coefficients
297 *
298 * Return: 0 if successful, error code (< 0) if error
299 **************************************************************************************/
300int Dequantize(AACDecInfo *aacDecInfo, int ch)
301{
302 int gp, cb, sfb, win, width, nSamps, gbMask;
303 int *coef;
304 const short *sfbTab;
305 unsigned char *sfbCodeBook;
306 short *scaleFactors;
307 PSInfoBase *psi;
308 ICSInfo *icsInfo;
309
310 /* validate pointers */
311 if (!aacDecInfo || !aacDecInfo->psInfoBase) {
312 return ERR_AAC_NULL_POINTER;
313 }
314 psi = (PSInfoBase *)(aacDecInfo->psInfoBase);
315 icsInfo = (ch == 1 && psi->commonWin == 1) ? &(psi->icsInfo[0]) : &(psi->icsInfo[ch]);
316
317 if (icsInfo->winSequence == 2) {
318 sfbTab = sfBandTabShort + sfBandTabShortOffset[psi->sampRateIdx];
319 nSamps = NSAMPS_SHORT;
320 } else {
321 sfbTab = sfBandTabLong + sfBandTabLongOffset[psi->sampRateIdx];
322 nSamps = NSAMPS_LONG;
323 }
324 coef = psi->coef[ch];
325 sfbCodeBook = psi->sfbCodeBook[ch];
326 scaleFactors = psi->scaleFactors[ch];
327
328 psi->intensityUsed[ch] = 0;
329 psi->pnsUsed[ch] = 0;
330 gbMask = 0;
331 for (gp = 0; gp < icsInfo->numWinGroup; gp++) {
332 for (win = 0; win < icsInfo->winGroupLen[gp]; win++) {
333 for (sfb = 0; sfb < icsInfo->maxSFB; sfb++) {
334 /* dequantize one scalefactor band (not necessary if codebook is intensity or PNS)
335 * for zero codebook, still run dequantizer in case non-zero pulse data was added
336 */
337 cb = (int)(sfbCodeBook[sfb]);
338 width = sfbTab[sfb + 1] - sfbTab[sfb];
339 if (cb >= 0 && cb <= 11) {
340 gbMask |= DequantBlock(coef, width, scaleFactors[sfb]);
341 } else if (cb == 13) {
342 psi->pnsUsed[ch] = 1;
343 } else if (cb == 14 || cb == 15) {
344 psi->intensityUsed[ch] = 1; /* should only happen if ch == 1 */
345 }
346 coef += width;
347 }
348 coef += (nSamps - sfbTab[icsInfo->maxSFB]);
349 }
350 sfbCodeBook += icsInfo->maxSFB;
351 scaleFactors += icsInfo->maxSFB;
352 }
353 aacDecInfo->pnsUsed |= psi->pnsUsed[ch]; /* set flag if PNS used for any channel */
354
355 /* calculate number of guard bits in dequantized data */
356 psi->gbCurrent[ch] = CLZ(gbMask) - 1;
357
358 return ERR_AAC_NONE;
359}
360
361/**************************************************************************************
362 * Function: DeinterleaveShortBlocks
363 *
364 * Description: deinterleave transform coefficients in short blocks for one channel
365 *
366 * Inputs: valid AACDecInfo struct (including unpacked, quantized coefficients)
367 * index of current channel
368 *
369 * Outputs: deinterleaved coefficients (window groups into 8 separate windows)
370 *
371 * Return: 0 if successful, error code (< 0) if error
372 *
373 * Notes: only necessary if deinterleaving not part of Huffman decoding
374 **************************************************************************************/
375int DeinterleaveShortBlocks(AACDecInfo *aacDecInfo, int ch)
376{
377 /* not used for this implementation - short block deinterleaving performed during Huffman decoding */
378 return ERR_AAC_NONE;
379}
380
generated by cgit at 2024-05-18 22:09:12 (GMT)