1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000,2001,2002 Josh Coalson
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 #include "private/fixed.h"
22 #include "FLAC/assert.h"
25 /* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
26 #define M_LN2 0.69314718055994530942
32 #define min(x,y) ((x) < (y)? (x) : (y))
37 #define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
39 unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
41 FLAC__int32 last_error_0 = data[-1];
42 FLAC__int32 last_error_1 = data[-1] - data[-2];
43 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
44 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
45 FLAC__int32 error, save;
46 FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
49 for(i = 0; i < data_len; i++) {
50 error = data[i] ; total_error_0 += local_abs(error); save = error;
51 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
52 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
53 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
54 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
57 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
59 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
61 else if(total_error_2 < min(total_error_3, total_error_4))
63 else if(total_error_3 < total_error_4)
68 residual_bits_per_sample[0] = (FLAC__real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double) data_len) / M_LN2 : 0.0);
69 residual_bits_per_sample[1] = (FLAC__real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double) data_len) / M_LN2 : 0.0);
70 residual_bits_per_sample[2] = (FLAC__real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double) data_len) / M_LN2 : 0.0);
71 residual_bits_per_sample[3] = (FLAC__real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double) data_len) / M_LN2 : 0.0);
72 residual_bits_per_sample[4] = (FLAC__real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double) data_len) / M_LN2 : 0.0);
77 unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__real residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
79 FLAC__int32 last_error_0 = data[-1];
80 FLAC__int32 last_error_1 = data[-1] - data[-2];
81 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
82 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
83 FLAC__int32 error, save;
84 /* total_error_* are 64-bits to avoid overflow when encoding
85 * erratic signals when the bits-per-sample and blocksize are
88 FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
91 for(i = 0; i < data_len; i++) {
92 error = data[i] ; total_error_0 += local_abs(error); save = error;
93 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
94 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
95 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
96 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
99 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
101 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
103 else if(total_error_2 < min(total_error_3, total_error_4))
105 else if(total_error_3 < total_error_4)
110 /* Estimate the expected number of bits per residual signal sample. */
111 /* 'total_error*' is linearly related to the variance of the residual */
112 /* signal, so we use it directly to compute E(|x|) */
113 #if defined _MSC_VER || defined __MINGW32__
114 /* with VC++ you have to spoon feed it the casting */
115 residual_bits_per_sample[0] = (FLAC__real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_0 / (double) data_len) / M_LN2 : 0.0);
116 residual_bits_per_sample[1] = (FLAC__real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_1 / (double) data_len) / M_LN2 : 0.0);
117 residual_bits_per_sample[2] = (FLAC__real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_2 / (double) data_len) / M_LN2 : 0.0);
118 residual_bits_per_sample[3] = (FLAC__real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_3 / (double) data_len) / M_LN2 : 0.0);
119 residual_bits_per_sample[4] = (FLAC__real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (double)(FLAC__int64)total_error_4 / (double) data_len) / M_LN2 : 0.0);
121 residual_bits_per_sample[0] = (FLAC__real)((data_len > 0 && total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double) data_len) / M_LN2 : 0.0);
122 residual_bits_per_sample[1] = (FLAC__real)((data_len > 0 && total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double) data_len) / M_LN2 : 0.0);
123 residual_bits_per_sample[2] = (FLAC__real)((data_len > 0 && total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double) data_len) / M_LN2 : 0.0);
124 residual_bits_per_sample[3] = (FLAC__real)((data_len > 0 && total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double) data_len) / M_LN2 : 0.0);
125 residual_bits_per_sample[4] = (FLAC__real)((data_len > 0 && total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double) data_len) / M_LN2 : 0.0);
131 void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
133 int i, idata_len = (int)data_len;
137 for(i = 0; i < idata_len; i++) {
138 residual[i] = data[i];
142 for(i = 0; i < idata_len; i++) {
143 residual[i] = data[i] - data[i-1];
147 for(i = 0; i < idata_len; i++) {
148 /* == data[i] - 2*data[i-1] + data[i-2] */
149 residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
153 for(i = 0; i < idata_len; i++) {
154 /* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
155 residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
159 for(i = 0; i < idata_len; i++) {
160 /* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
161 residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
169 void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
171 int i, idata_len = (int)data_len;
175 for(i = 0; i < idata_len; i++) {
176 data[i] = residual[i];
180 for(i = 0; i < idata_len; i++) {
181 data[i] = residual[i] + data[i-1];
185 for(i = 0; i < idata_len; i++) {
186 /* == residual[i] + 2*data[i-1] - data[i-2] */
187 data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
191 for(i = 0; i < idata_len; i++) {
192 /* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
193 data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
197 for(i = 0; i < idata_len; i++) {
198 /* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
199 data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];