1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000,2001,2002,2003,2004,2005 Josh Coalson
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
11 * - 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.
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.
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.
33 #include "private/bitmath.h"
34 #include "private/fixed.h"
35 #include "FLAC/assert.h"
38 /* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
39 #define M_LN2 0.69314718055994530942
45 #define min(x,y) ((x) < (y)? (x) : (y))
50 #define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
52 #ifdef FLAC__INTEGER_ONLY_LIBRARY
53 /* rbps stands for residual bits per sample
56 * rbps = log (-----------)
59 static FLAC__fixedpoint local__compute_rbps_integerized(FLAC__uint32 err, FLAC__uint32 n)
62 unsigned bits; /* the number of bits required to represent a number */
63 int fracbits; /* the number of bits of rbps that comprise the fractional part */
65 FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
66 FLAC__ASSERT(err > 0);
69 FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
73 * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
74 * These allow us later to know we won't lose too much precision in the
75 * fixed-point division (err<<fracbits)/n.
78 fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2(err)+1);
82 /* err now holds err/n with fracbits fractional bits */
85 * Whittle err down to 16 bits max. 16 significant bits is enough for
88 FLAC__ASSERT(err > 0);
89 bits = FLAC__bitmath_ilog2(err)+1;
92 fracbits -= (bits-16);
94 rbps = (FLAC__uint32)err;
96 /* Multiply by fixed-point version of ln(2), with 16 fractional bits */
99 FLAC__ASSERT(fracbits >= 0);
101 /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
103 const int f = fracbits & 3;
110 rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
116 * The return value must have 16 fractional bits. Since the whole part
117 * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
118 * must be >= -3, these assertion allows us to be able to shift rbps
119 * left if necessary to get 16 fracbits without losing any bits of the
120 * whole part of rbps.
122 * There is a slight chance due to accumulated error that the whole part
123 * will require 6 bits, so we use 6 in the assertion. Really though as
124 * long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
126 FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
127 FLAC__ASSERT(fracbits >= -3);
129 /* now shift the decimal point into place */
131 return rbps << (16-fracbits);
132 else if(fracbits > 16)
133 return rbps >> (fracbits-16);
138 static FLAC__fixedpoint local__compute_rbps_wide_integerized(FLAC__uint64 err, FLAC__uint32 n)
141 unsigned bits; /* the number of bits required to represent a number */
142 int fracbits; /* the number of bits of rbps that comprise the fractional part */
144 FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
145 FLAC__ASSERT(err > 0);
148 FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
152 * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
153 * These allow us later to know we won't lose too much precision in the
154 * fixed-point division (err<<fracbits)/n.
157 fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2_wide(err)+1);
161 /* err now holds err/n with fracbits fractional bits */
164 * Whittle err down to 16 bits max. 16 significant bits is enough for
167 FLAC__ASSERT(err > 0);
168 bits = FLAC__bitmath_ilog2_wide(err)+1;
171 fracbits -= (bits-16);
173 rbps = (FLAC__uint32)err;
175 /* Multiply by fixed-point version of ln(2), with 16 fractional bits */
176 rbps *= FLAC__FP_LN2;
178 FLAC__ASSERT(fracbits >= 0);
180 /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
182 const int f = fracbits & 3;
189 rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
195 * The return value must have 16 fractional bits. Since the whole part
196 * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
197 * must be >= -3, these assertion allows us to be able to shift rbps
198 * left if necessary to get 16 fracbits without losing any bits of the
199 * whole part of rbps.
201 * There is a slight chance due to accumulated error that the whole part
202 * will require 6 bits, so we use 6 in the assertion. Really though as
203 * long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
205 FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
206 FLAC__ASSERT(fracbits >= -3);
208 /* now shift the decimal point into place */
210 return rbps << (16-fracbits);
211 else if(fracbits > 16)
212 return rbps >> (fracbits-16);
218 #ifndef FLAC__INTEGER_ONLY_LIBRARY
219 unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
221 unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
224 FLAC__int32 last_error_0 = data[-1];
225 FLAC__int32 last_error_1 = data[-1] - data[-2];
226 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
227 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
228 FLAC__int32 error, save;
229 FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
232 for(i = 0; i < data_len; i++) {
233 error = data[i] ; total_error_0 += local_abs(error); save = error;
234 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
235 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
236 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
237 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
240 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
242 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
244 else if(total_error_2 < min(total_error_3, total_error_4))
246 else if(total_error_3 < total_error_4)
251 /* Estimate the expected number of bits per residual signal sample. */
252 /* 'total_error*' is linearly related to the variance of the residual */
253 /* signal, so we use it directly to compute E(|x|) */
254 FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
255 FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
256 FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
257 FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
258 FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
259 #ifndef FLAC__INTEGER_ONLY_LIBRARY
260 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);
261 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);
262 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);
263 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);
264 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);
266 residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_integerized(total_error_0, data_len) : 0;
267 residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_integerized(total_error_1, data_len) : 0;
268 residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_integerized(total_error_2, data_len) : 0;
269 residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_integerized(total_error_3, data_len) : 0;
270 residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_integerized(total_error_4, data_len) : 0;
276 #ifndef FLAC__INTEGER_ONLY_LIBRARY
277 unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
279 unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
282 FLAC__int32 last_error_0 = data[-1];
283 FLAC__int32 last_error_1 = data[-1] - data[-2];
284 FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
285 FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
286 FLAC__int32 error, save;
287 /* total_error_* are 64-bits to avoid overflow when encoding
288 * erratic signals when the bits-per-sample and blocksize are
291 FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
294 for(i = 0; i < data_len; i++) {
295 error = data[i] ; total_error_0 += local_abs(error); save = error;
296 error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
297 error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
298 error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
299 error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
302 if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
304 else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
306 else if(total_error_2 < min(total_error_3, total_error_4))
308 else if(total_error_3 < total_error_4)
313 /* Estimate the expected number of bits per residual signal sample. */
314 /* 'total_error*' is linearly related to the variance of the residual */
315 /* signal, so we use it directly to compute E(|x|) */
316 FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
317 FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
318 FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
319 FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
320 FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
321 #ifndef FLAC__INTEGER_ONLY_LIBRARY
322 #if defined _MSC_VER || defined __MINGW32__
323 /* with MSVC you have to spoon feed it the casting */
324 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);
325 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);
326 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);
327 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);
328 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);
330 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);
331 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);
332 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);
333 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);
334 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);
337 residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_wide_integerized(total_error_0, data_len) : 0;
338 residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_wide_integerized(total_error_1, data_len) : 0;
339 residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_wide_integerized(total_error_2, data_len) : 0;
340 residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_wide_integerized(total_error_3, data_len) : 0;
341 residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_wide_integerized(total_error_4, data_len) : 0;
347 void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
349 const int idata_len = (int)data_len;
354 for(i = 0; i < idata_len; i++) {
355 residual[i] = data[i];
359 for(i = 0; i < idata_len; i++) {
360 residual[i] = data[i] - data[i-1];
364 for(i = 0; i < idata_len; i++) {
365 /* == data[i] - 2*data[i-1] + data[i-2] */
366 residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
370 for(i = 0; i < idata_len; i++) {
371 /* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
372 residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
376 for(i = 0; i < idata_len; i++) {
377 /* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
378 residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
386 void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
388 int i, idata_len = (int)data_len;
392 for(i = 0; i < idata_len; i++) {
393 data[i] = residual[i];
397 for(i = 0; i < idata_len; i++) {
398 data[i] = residual[i] + data[i-1];
402 for(i = 0; i < idata_len; i++) {
403 /* == residual[i] + 2*data[i-1] - data[i-2] */
404 data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
408 for(i = 0; i < idata_len; i++) {
409 /* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
410 data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
414 for(i = 0; i < idata_len; i++) {
415 /* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
416 data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];