blob: d432962a12e7c7ab9fe62fd5e0f7f07f07bd5026 [file] [log] [blame]
Josh Coalson26560dd2001-02-08 00:38:41 +00001/* libFLAC - Free Lossless Audio Codec library
Josh Coalson0395dac2006-04-25 06:59:33 +00002 * Copyright (C) 2000,2001,2002,2003,2004,2005,2006 Josh Coalson
Josh Coalsonbb7f6b92000-12-10 04:09:52 +00003 *
Josh Coalsonafd81072003-01-31 23:34:56 +00004 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
Josh Coalsonbb7f6b92000-12-10 04:09:52 +00007 *
Josh Coalsonafd81072003-01-31 23:34:56 +00008 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000010 *
Josh Coalsonafd81072003-01-31 23:34:56 +000011 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * - Neither the name of the Xiph.org Foundation nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000030 */
31
Josh Coalsonb1ec7962006-05-24 04:41:36 +000032#if HAVE_CONFIG_H
33# include <config.h>
34#endif
35
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000036#include <math.h>
Josh Coalson5f2b46d2004-11-09 01:34:01 +000037#include "private/bitmath.h"
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000038#include "private/fixed.h"
Josh Coalson1b689822001-05-31 20:11:02 +000039#include "FLAC/assert.h"
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000040
41#ifndef M_LN2
42/* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
43#define M_LN2 0.69314718055994530942
44#endif
45
46#ifdef min
47#undef min
48#endif
49#define min(x,y) ((x) < (y)? (x) : (y))
50
51#ifdef local_abs
52#undef local_abs
53#endif
Josh Coalsonfe9ba6f2001-02-28 23:44:27 +000054#define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
Josh Coalsonbb7f6b92000-12-10 04:09:52 +000055
Josh Coalson5f2b46d2004-11-09 01:34:01 +000056#ifdef FLAC__INTEGER_ONLY_LIBRARY
57/* rbps stands for residual bits per sample
58 *
59 * (ln(2) * err)
60 * rbps = log (-----------)
61 * 2 ( n )
62 */
63static FLAC__fixedpoint local__compute_rbps_integerized(FLAC__uint32 err, FLAC__uint32 n)
64{
65 FLAC__uint32 rbps;
66 unsigned bits; /* the number of bits required to represent a number */
67 int fracbits; /* the number of bits of rbps that comprise the fractional part */
68
69 FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
70 FLAC__ASSERT(err > 0);
71 FLAC__ASSERT(n > 0);
72
73 FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
74 if(err <= n)
75 return 0;
76 /*
77 * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
78 * These allow us later to know we won't lose too much precision in the
79 * fixed-point division (err<<fracbits)/n.
80 */
81
82 fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2(err)+1);
83
84 err <<= fracbits;
85 err /= n;
86 /* err now holds err/n with fracbits fractional bits */
87
88 /*
89 * Whittle err down to 16 bits max. 16 significant bits is enough for
90 * our purposes.
91 */
92 FLAC__ASSERT(err > 0);
93 bits = FLAC__bitmath_ilog2(err)+1;
94 if(bits > 16) {
95 err >>= (bits-16);
96 fracbits -= (bits-16);
97 }
98 rbps = (FLAC__uint32)err;
99
100 /* Multiply by fixed-point version of ln(2), with 16 fractional bits */
101 rbps *= FLAC__FP_LN2;
102 fracbits += 16;
103 FLAC__ASSERT(fracbits >= 0);
104
105 /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
106 {
107 const int f = fracbits & 3;
108 if(f) {
109 rbps >>= f;
110 fracbits -= f;
111 }
112 }
113
114 rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
115
116 if(rbps == 0)
117 return 0;
118
119 /*
120 * The return value must have 16 fractional bits. Since the whole part
121 * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
122 * must be >= -3, these assertion allows us to be able to shift rbps
123 * left if necessary to get 16 fracbits without losing any bits of the
124 * whole part of rbps.
125 *
126 * There is a slight chance due to accumulated error that the whole part
127 * will require 6 bits, so we use 6 in the assertion. Really though as
128 * long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
129 */
130 FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
131 FLAC__ASSERT(fracbits >= -3);
132
133 /* now shift the decimal point into place */
134 if(fracbits < 16)
135 return rbps << (16-fracbits);
136 else if(fracbits > 16)
137 return rbps >> (fracbits-16);
138 else
139 return rbps;
140}
141
142static FLAC__fixedpoint local__compute_rbps_wide_integerized(FLAC__uint64 err, FLAC__uint32 n)
143{
144 FLAC__uint32 rbps;
145 unsigned bits; /* the number of bits required to represent a number */
146 int fracbits; /* the number of bits of rbps that comprise the fractional part */
147
148 FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
149 FLAC__ASSERT(err > 0);
150 FLAC__ASSERT(n > 0);
151
152 FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
153 if(err <= n)
154 return 0;
155 /*
156 * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
157 * These allow us later to know we won't lose too much precision in the
158 * fixed-point division (err<<fracbits)/n.
159 */
160
161 fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2_wide(err)+1);
162
163 err <<= fracbits;
164 err /= n;
165 /* err now holds err/n with fracbits fractional bits */
166
167 /*
168 * Whittle err down to 16 bits max. 16 significant bits is enough for
169 * our purposes.
170 */
171 FLAC__ASSERT(err > 0);
172 bits = FLAC__bitmath_ilog2_wide(err)+1;
173 if(bits > 16) {
174 err >>= (bits-16);
175 fracbits -= (bits-16);
176 }
177 rbps = (FLAC__uint32)err;
178
179 /* Multiply by fixed-point version of ln(2), with 16 fractional bits */
180 rbps *= FLAC__FP_LN2;
181 fracbits += 16;
182 FLAC__ASSERT(fracbits >= 0);
183
184 /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
185 {
186 const int f = fracbits & 3;
187 if(f) {
188 rbps >>= f;
189 fracbits -= f;
190 }
191 }
192
193 rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
194
195 if(rbps == 0)
196 return 0;
197
198 /*
199 * The return value must have 16 fractional bits. Since the whole part
200 * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
201 * must be >= -3, these assertion allows us to be able to shift rbps
202 * left if necessary to get 16 fracbits without losing any bits of the
203 * whole part of rbps.
204 *
205 * There is a slight chance due to accumulated error that the whole part
206 * will require 6 bits, so we use 6 in the assertion. Really though as
207 * long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
208 */
209 FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
210 FLAC__ASSERT(fracbits >= -3);
211
212 /* now shift the decimal point into place */
213 if(fracbits < 16)
214 return rbps << (16-fracbits);
215 else if(fracbits > 16)
216 return rbps >> (fracbits-16);
217 else
218 return rbps;
219}
220#endif
221
222#ifndef FLAC__INTEGER_ONLY_LIBRARY
Josh Coalson09758432004-10-20 00:21:50 +0000223unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000224#else
225unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
226#endif
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000227{
Josh Coalson77e3f312001-06-23 03:03:24 +0000228 FLAC__int32 last_error_0 = data[-1];
229 FLAC__int32 last_error_1 = data[-1] - data[-2];
230 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
231 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
232 FLAC__int32 error, save;
233 FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000234 unsigned i, order;
235
236 for(i = 0; i < data_len; i++) {
Josh Coalsond80c18e2001-05-18 18:47:55 +0000237 error = data[i] ; total_error_0 += local_abs(error); save = error;
238 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
239 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
240 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
241 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
Josh Coalson78444242001-03-30 00:43:46 +0000242 }
243
244 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
245 order = 0;
246 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
247 order = 1;
248 else if(total_error_2 < min(total_error_3, total_error_4))
249 order = 2;
250 else if(total_error_3 < total_error_4)
251 order = 3;
252 else
253 order = 4;
254
Josh Coalson427048f2002-08-27 05:44:57 +0000255 /* Estimate the expected number of bits per residual signal sample. */
256 /* 'total_error*' is linearly related to the variance of the residual */
257 /* signal, so we use it directly to compute E(|x|) */
258 FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
259 FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
260 FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
261 FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
262 FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000263#ifndef FLAC__INTEGER_ONLY_LIBRARY
Josh Coalson09758432004-10-20 00:21:50 +0000264 residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
265 residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
266 residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
267 residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
268 residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000269#else
270 residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_integerized(total_error_0, data_len) : 0;
271 residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_integerized(total_error_1, data_len) : 0;
272 residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_integerized(total_error_2, data_len) : 0;
273 residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_integerized(total_error_3, data_len) : 0;
274 residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_integerized(total_error_4, data_len) : 0;
275#endif
Josh Coalson78444242001-03-30 00:43:46 +0000276
277 return order;
278}
279
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000280#ifndef FLAC__INTEGER_ONLY_LIBRARY
Josh Coalson09758432004-10-20 00:21:50 +0000281unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000282#else
283unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
284#endif
Josh Coalson78444242001-03-30 00:43:46 +0000285{
Josh Coalson77e3f312001-06-23 03:03:24 +0000286 FLAC__int32 last_error_0 = data[-1];
287 FLAC__int32 last_error_1 = data[-1] - data[-2];
288 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
289 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
290 FLAC__int32 error, save;
Josh Coalson78444242001-03-30 00:43:46 +0000291 /* total_error_* are 64-bits to avoid overflow when encoding
292 * erratic signals when the bits-per-sample and blocksize are
293 * large.
294 */
Josh Coalson77e3f312001-06-23 03:03:24 +0000295 FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
Josh Coalson78444242001-03-30 00:43:46 +0000296 unsigned i, order;
297
298 for(i = 0; i < data_len; i++) {
Josh Coalsoneee20a52001-05-18 18:49:19 +0000299 error = data[i] ; total_error_0 += local_abs(error); save = error;
300 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
301 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
302 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
303 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000304 }
305
306 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
307 order = 0;
308 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
309 order = 1;
310 else if(total_error_2 < min(total_error_3, total_error_4))
311 order = 2;
312 else if(total_error_3 < total_error_4)
313 order = 3;
314 else
315 order = 4;
316
317 /* Estimate the expected number of bits per residual signal sample. */
318 /* 'total_error*' is linearly related to the variance of the residual */
319 /* signal, so we use it directly to compute E(|x|) */
Josh Coalson427048f2002-08-27 05:44:57 +0000320 FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
321 FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
322 FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
323 FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
324 FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000325#ifndef FLAC__INTEGER_ONLY_LIBRARY
Josh Coalson40333b12001-11-13 21:37:04 +0000326#if defined _MSC_VER || defined __MINGW32__
Josh Coalson49262502004-12-30 03:48:42 +0000327 /* with MSVC you have to spoon feed it the casting */
Josh Coalson09758432004-10-20 00:21:50 +0000328 residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
329 residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
330 residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
331 residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
332 residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
Josh Coalson59f4a992001-04-01 05:55:01 +0000333#else
Josh Coalson09758432004-10-20 00:21:50 +0000334 residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
335 residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
336 residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
337 residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
338 residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
Josh Coalson59f4a992001-04-01 05:55:01 +0000339#endif
Josh Coalson5f2b46d2004-11-09 01:34:01 +0000340#else
341 residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_wide_integerized(total_error_0, data_len) : 0;
342 residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_wide_integerized(total_error_1, data_len) : 0;
343 residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_wide_integerized(total_error_2, data_len) : 0;
344 residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_wide_integerized(total_error_3, data_len) : 0;
345 residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_wide_integerized(total_error_4, data_len) : 0;
346#endif
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000347
348 return order;
349}
350
Josh Coalson77e3f312001-06-23 03:03:24 +0000351void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000352{
Josh Coalson64df7152002-10-11 06:24:12 +0000353 const int idata_len = (int)data_len;
354 int i;
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000355
356 switch(order) {
357 case 0:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000358 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000359 residual[i] = data[i];
360 }
361 break;
362 case 1:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000363 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000364 residual[i] = data[i] - data[i-1];
365 }
366 break;
367 case 2:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000368 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000369 /* == data[i] - 2*data[i-1] + data[i-2] */
370 residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
371 }
372 break;
373 case 3:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000374 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000375 /* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
376 residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
377 }
378 break;
379 case 4:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000380 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000381 /* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
382 residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
383 }
384 break;
385 default:
Josh Coalson1b689822001-05-31 20:11:02 +0000386 FLAC__ASSERT(0);
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000387 }
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000388}
389
Josh Coalson77e3f312001-06-23 03:03:24 +0000390void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000391{
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000392 int i, idata_len = (int)data_len;
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000393
394 switch(order) {
395 case 0:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000396 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000397 data[i] = residual[i];
398 }
399 break;
400 case 1:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000401 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000402 data[i] = residual[i] + data[i-1];
403 }
404 break;
405 case 2:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000406 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000407 /* == residual[i] + 2*data[i-1] - data[i-2] */
408 data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
409 }
410 break;
411 case 3:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000412 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000413 /* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
414 data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
415 }
416 break;
417 case 4:
Josh Coalsona16d8ad2001-05-21 23:43:35 +0000418 for(i = 0; i < idata_len; i++) {
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000419 /* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
420 data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];
421 }
422 break;
423 default:
Josh Coalson1b689822001-05-31 20:11:02 +0000424 FLAC__ASSERT(0);
Josh Coalsonbb7f6b92000-12-10 04:09:52 +0000425 }
426}