1 /* Copyright (c) 2007-2008 CSIRO
2 Copyright (c) 2007-2009 Xiph.Org Foundation
3 Written by Jean-Marc Valin */
4 /**
5 @file pitch.c
6 @brief Pitch analysis
7 */
8
9 /*
10 Redistribution and use in source and binary forms, with or without
11 modification, are permitted provided that the following conditions
12 are met:
13
14 - Redistributions of source code must retain the above copyright
15 notice, this list of conditions and the following disclaimer.
16
17 - Redistributions in binary form must reproduce the above copyright
18 notice, this list of conditions and the following disclaimer in the
19 documentation and/or other materials provided with the distribution.
20
21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
25 OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
28 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #ifdef HAVE_CONFIG_H
35 #include "config.h"
36 #endif
37
38 #include "pitch.h"
39 #include "os_support.h"
40 #include "modes.h"
41 #include "stack_alloc.h"
42 #include "mathops.h"
43 #include "celt_lpc.h"
44
find_best_pitch(opus_val32 * xcorr,opus_val16 * y,int len,int max_pitch,int * best_pitch,int yshift,opus_val32 maxcorr)45 static void find_best_pitch(opus_val32 *xcorr, opus_val16 *y, int len,
46 int max_pitch, int *best_pitch
47 #ifdef FIXED_POINT
48 , int yshift, opus_val32 maxcorr
49 #endif
50 )
51 {
52 int i, j;
53 opus_val32 Syy=1;
54 opus_val16 best_num[2];
55 opus_val32 best_den[2];
56 #ifdef FIXED_POINT
57 int xshift;
58
59 xshift = celt_ilog2(maxcorr)-14;
60 #endif
61
62 best_num[0] = -1;
63 best_num[1] = -1;
64 best_den[0] = 0;
65 best_den[1] = 0;
66 best_pitch[0] = 0;
67 best_pitch[1] = 1;
68 for (j=0;j<len;j++)
69 Syy = ADD32(Syy, SHR32(MULT16_16(y[j],y[j]), yshift));
70 for (i=0;i<max_pitch;i++)
71 {
72 if (xcorr[i]>0)
73 {
74 opus_val16 num;
75 opus_val32 xcorr16;
76 xcorr16 = EXTRACT16(VSHR32(xcorr[i], xshift));
77 #ifndef FIXED_POINT
78 /* Considering the range of xcorr16, this should avoid both underflows
79 and overflows (inf) when squaring xcorr16 */
80 xcorr16 *= 1e-12f;
81 #endif
82 num = MULT16_16_Q15(xcorr16,xcorr16);
83 if (MULT16_32_Q15(num,best_den[1]) > MULT16_32_Q15(best_num[1],Syy))
84 {
85 if (MULT16_32_Q15(num,best_den[0]) > MULT16_32_Q15(best_num[0],Syy))
86 {
87 best_num[1] = best_num[0];
88 best_den[1] = best_den[0];
89 best_pitch[1] = best_pitch[0];
90 best_num[0] = num;
91 best_den[0] = Syy;
92 best_pitch[0] = i;
93 } else {
94 best_num[1] = num;
95 best_den[1] = Syy;
96 best_pitch[1] = i;
97 }
98 }
99 }
100 Syy += SHR32(MULT16_16(y[i+len],y[i+len]),yshift) - SHR32(MULT16_16(y[i],y[i]),yshift);
101 Syy = MAX32(1, Syy);
102 }
103 }
104
celt_fir5(const opus_val16 * x,const opus_val16 * num,opus_val16 * y,int N,opus_val16 * mem)105 static void celt_fir5(const opus_val16 *x,
106 const opus_val16 *num,
107 opus_val16 *y,
108 int N,
109 opus_val16 *mem)
110 {
111 int i;
112 opus_val16 num0, num1, num2, num3, num4;
113 opus_val32 mem0, mem1, mem2, mem3, mem4;
114 num0=num[0];
115 num1=num[1];
116 num2=num[2];
117 num3=num[3];
118 num4=num[4];
119 mem0=mem[0];
120 mem1=mem[1];
121 mem2=mem[2];
122 mem3=mem[3];
123 mem4=mem[4];
124 for (i=0;i<N;i++)
125 {
126 opus_val32 sum = SHL32(EXTEND32(x[i]), SIG_SHIFT);
127 sum = MAC16_16(sum,num0,mem0);
128 sum = MAC16_16(sum,num1,mem1);
129 sum = MAC16_16(sum,num2,mem2);
130 sum = MAC16_16(sum,num3,mem3);
131 sum = MAC16_16(sum,num4,mem4);
132 mem4 = mem3;
133 mem3 = mem2;
134 mem2 = mem1;
135 mem1 = mem0;
136 mem0 = x[i];
137 y[i] = ROUND16(sum, SIG_SHIFT);
138 }
139 mem[0]=mem0;
140 mem[1]=mem1;
141 mem[2]=mem2;
142 mem[3]=mem3;
143 mem[4]=mem4;
144 }
145
146
pitch_downsample(celt_sig * OPUS_RESTRICT x[],opus_val16 * OPUS_RESTRICT x_lp,int len,int C)147 void pitch_downsample(celt_sig * OPUS_RESTRICT x[], opus_val16 * OPUS_RESTRICT x_lp,
148 int len, int C)
149 {
150 int i;
151 opus_val32 ac[5];
152 opus_val16 tmp=Q15ONE;
153 opus_val16 lpc[4], mem[5]={0,0,0,0,0};
154 opus_val16 lpc2[5];
155 opus_val16 c1 = QCONST16(.8f,15);
156 #ifdef FIXED_POINT
157 int shift;
158 opus_val32 maxabs = celt_maxabs32(x[0], len);
159 if (C==2)
160 {
161 opus_val32 maxabs_1 = celt_maxabs32(x[1], len);
162 maxabs = MAX32(maxabs, maxabs_1);
163 }
164 if (maxabs<1)
165 maxabs=1;
166 shift = celt_ilog2(maxabs)-10;
167 if (shift<0)
168 shift=0;
169 if (C==2)
170 shift++;
171 #endif
172 for (i=1;i<len>>1;i++)
173 x_lp[i] = SHR32(HALF32(HALF32(x[0][(2*i-1)]+x[0][(2*i+1)])+x[0][2*i]), shift);
174 x_lp[0] = SHR32(HALF32(HALF32(x[0][1])+x[0][0]), shift);
175 if (C==2)
176 {
177 for (i=1;i<len>>1;i++)
178 x_lp[i] += SHR32(HALF32(HALF32(x[1][(2*i-1)]+x[1][(2*i+1)])+x[1][2*i]), shift);
179 x_lp[0] += SHR32(HALF32(HALF32(x[1][1])+x[1][0]), shift);
180 }
181
182 _celt_autocorr(x_lp, ac, NULL, 0,
183 4, len>>1);
184
185 /* Noise floor -40 dB */
186 #ifdef FIXED_POINT
187 ac[0] += SHR32(ac[0],13);
188 #else
189 ac[0] *= 1.0001f;
190 #endif
191 /* Lag windowing */
192 for (i=1;i<=4;i++)
193 {
194 /*ac[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/
195 #ifdef FIXED_POINT
196 ac[i] -= MULT16_32_Q15(2*i*i, ac[i]);
197 #else
198 ac[i] -= ac[i]*(.008f*i)*(.008f*i);
199 #endif
200 }
201
202 _celt_lpc(lpc, ac, 4);
203 for (i=0;i<4;i++)
204 {
205 tmp = MULT16_16_Q15(QCONST16(.9f,15), tmp);
206 lpc[i] = MULT16_16_Q15(lpc[i], tmp);
207 }
208 /* Add a zero */
209 lpc2[0] = lpc[0] + QCONST16(.8f,SIG_SHIFT);
210 lpc2[1] = lpc[1] + MULT16_16_Q15(c1,lpc[0]);
211 lpc2[2] = lpc[2] + MULT16_16_Q15(c1,lpc[1]);
212 lpc2[3] = lpc[3] + MULT16_16_Q15(c1,lpc[2]);
213 lpc2[4] = MULT16_16_Q15(c1,lpc[3]);
214 celt_fir5(x_lp, lpc2, x_lp, len>>1, mem);
215 }
216
217 #if 0 /* This is a simple version of the pitch correlation that should work
218 well on DSPs like Blackfin and TI C5x/C6x */
219
220 #ifdef FIXED_POINT
221 opus_val32
222 #else
223 void
224 #endif
225 celt_pitch_xcorr(opus_val16 *x, opus_val16 *y, opus_val32 *xcorr, int len, int max_pitch)
226 {
227 int i, j;
228 #ifdef FIXED_POINT
229 opus_val32 maxcorr=1;
230 #endif
231 for (i=0;i<max_pitch;i++)
232 {
233 opus_val32 sum = 0;
234 for (j=0;j<len;j++)
235 sum = MAC16_16(sum, x[j],y[i+j]);
236 xcorr[i] = sum;
237 #ifdef FIXED_POINT
238 maxcorr = MAX32(maxcorr, sum);
239 #endif
240 }
241 #ifdef FIXED_POINT
242 return maxcorr;
243 #endif
244 }
245
246 #else /* Unrolled version of the pitch correlation -- runs faster on x86 and ARM */
247
248 #ifdef FIXED_POINT
249 opus_val32
250 #else
251 void
252 #endif
celt_pitch_xcorr(const opus_val16 * _x,const opus_val16 * _y,opus_val32 * xcorr,int len,int max_pitch)253 celt_pitch_xcorr(const opus_val16 *_x, const opus_val16 *_y, opus_val32 *xcorr, int len, int max_pitch)
254 {
255 int i,j;
256 #ifdef FIXED_POINT
257 opus_val32 maxcorr=1;
258 #endif
259 for (i=0;i<max_pitch-3;i+=4)
260 {
261 opus_val32 sum[4]={0,0,0,0};
262 xcorr_kernel(_x, _y+i, sum, len);
263 xcorr[i]=sum[0];
264 xcorr[i+1]=sum[1];
265 xcorr[i+2]=sum[2];
266 xcorr[i+3]=sum[3];
267 #ifdef FIXED_POINT
268 sum[0] = MAX32(sum[0], sum[1]);
269 sum[2] = MAX32(sum[2], sum[3]);
270 sum[0] = MAX32(sum[0], sum[2]);
271 maxcorr = MAX32(maxcorr, sum[0]);
272 #endif
273 }
274 /* In case max_pitch isn't a multiple of 4, do non-unrolled version. */
275 for (;i<max_pitch;i++)
276 {
277 opus_val32 sum = 0;
278 for (j=0;j<len;j++)
279 sum = MAC16_16(sum, _x[j],_y[i+j]);
280 xcorr[i] = sum;
281 #ifdef FIXED_POINT
282 maxcorr = MAX32(maxcorr, sum);
283 #endif
284 }
285 #ifdef FIXED_POINT
286 return maxcorr;
287 #endif
288 }
289
290 #endif
pitch_search(const opus_val16 * OPUS_RESTRICT x_lp,opus_val16 * OPUS_RESTRICT y,int len,int max_pitch,int * pitch)291 void pitch_search(const opus_val16 * OPUS_RESTRICT x_lp, opus_val16 * OPUS_RESTRICT y,
292 int len, int max_pitch, int *pitch)
293 {
294 int i, j;
295 int lag;
296 int best_pitch[2]={0,0};
297 VARDECL(opus_val16, x_lp4);
298 VARDECL(opus_val16, y_lp4);
299 VARDECL(opus_val32, xcorr);
300 #ifdef FIXED_POINT
301 opus_val32 maxcorr;
302 opus_val32 xmax, ymax;
303 int shift=0;
304 #endif
305 int offset;
306
307 SAVE_STACK;
308
309 celt_assert(len>0);
310 celt_assert(max_pitch>0);
311 lag = len+max_pitch;
312
313 ALLOC(x_lp4, len>>2, opus_val16);
314 ALLOC(y_lp4, lag>>2, opus_val16);
315 ALLOC(xcorr, max_pitch>>1, opus_val32);
316
317 /* Downsample by 2 again */
318 for (j=0;j<len>>2;j++)
319 x_lp4[j] = x_lp[2*j];
320 for (j=0;j<lag>>2;j++)
321 y_lp4[j] = y[2*j];
322
323 #ifdef FIXED_POINT
324 xmax = celt_maxabs16(x_lp4, len>>2);
325 ymax = celt_maxabs16(y_lp4, lag>>2);
326 shift = celt_ilog2(MAX32(1, MAX32(xmax, ymax)))-11;
327 if (shift>0)
328 {
329 for (j=0;j<len>>2;j++)
330 x_lp4[j] = SHR16(x_lp4[j], shift);
331 for (j=0;j<lag>>2;j++)
332 y_lp4[j] = SHR16(y_lp4[j], shift);
333 /* Use double the shift for a MAC */
334 shift *= 2;
335 } else {
336 shift = 0;
337 }
338 #endif
339
340 /* Coarse search with 4x decimation */
341
342 #ifdef FIXED_POINT
343 maxcorr =
344 #endif
345 celt_pitch_xcorr(x_lp4, y_lp4, xcorr, len>>2, max_pitch>>2);
346
347 find_best_pitch(xcorr, y_lp4, len>>2, max_pitch>>2, best_pitch
348 #ifdef FIXED_POINT
349 , 0, maxcorr
350 #endif
351 );
352
353 /* Finer search with 2x decimation */
354 #ifdef FIXED_POINT
355 maxcorr=1;
356 #endif
357 for (i=0;i<max_pitch>>1;i++)
358 {
359 opus_val32 sum=0;
360 xcorr[i] = 0;
361 if (abs(i-2*best_pitch[0])>2 && abs(i-2*best_pitch[1])>2)
362 continue;
363 for (j=0;j<len>>1;j++)
364 sum += SHR32(MULT16_16(x_lp[j],y[i+j]), shift);
365 xcorr[i] = MAX32(-1, sum);
366 #ifdef FIXED_POINT
367 maxcorr = MAX32(maxcorr, sum);
368 #endif
369 }
370 find_best_pitch(xcorr, y, len>>1, max_pitch>>1, best_pitch
371 #ifdef FIXED_POINT
372 , shift+1, maxcorr
373 #endif
374 );
375
376 /* Refine by pseudo-interpolation */
377 if (best_pitch[0]>0 && best_pitch[0]<(max_pitch>>1)-1)
378 {
379 opus_val32 a, b, c;
380 a = xcorr[best_pitch[0]-1];
381 b = xcorr[best_pitch[0]];
382 c = xcorr[best_pitch[0]+1];
383 if ((c-a) > MULT16_32_Q15(QCONST16(.7f,15),b-a))
384 offset = 1;
385 else if ((a-c) > MULT16_32_Q15(QCONST16(.7f,15),b-c))
386 offset = -1;
387 else
388 offset = 0;
389 } else {
390 offset = 0;
391 }
392 *pitch = 2*best_pitch[0]-offset;
393
394 RESTORE_STACK;
395 }
396
397 static const int second_check[16] = {0, 0, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2};
remove_doubling(opus_val16 * x,int maxperiod,int minperiod,int N,int * T0_,int prev_period,opus_val16 prev_gain)398 opus_val16 remove_doubling(opus_val16 *x, int maxperiod, int minperiod,
399 int N, int *T0_, int prev_period, opus_val16 prev_gain)
400 {
401 int k, i, T, T0;
402 opus_val16 g, g0;
403 opus_val16 pg;
404 opus_val32 xy,xx,yy,xy2;
405 opus_val32 xcorr[3];
406 opus_val32 best_xy, best_yy;
407 int offset;
408 int minperiod0;
409 VARDECL(opus_val32, yy_lookup);
410 SAVE_STACK;
411
412 minperiod0 = minperiod;
413 maxperiod /= 2;
414 minperiod /= 2;
415 *T0_ /= 2;
416 prev_period /= 2;
417 N /= 2;
418 x += maxperiod;
419 if (*T0_>=maxperiod)
420 *T0_=maxperiod-1;
421
422 T = T0 = *T0_;
423 ALLOC(yy_lookup, maxperiod+1, opus_val32);
424 dual_inner_prod(x, x, x-T0, N, &xx, &xy);
425 yy_lookup[0] = xx;
426 yy=xx;
427 for (i=1;i<=maxperiod;i++)
428 {
429 yy = yy+MULT16_16(x[-i],x[-i])-MULT16_16(x[N-i],x[N-i]);
430 yy_lookup[i] = MAX32(0, yy);
431 }
432 yy = yy_lookup[T0];
433 best_xy = xy;
434 best_yy = yy;
435 #ifdef FIXED_POINT
436 {
437 opus_val32 x2y2;
438 int sh, t;
439 x2y2 = 1+HALF32(MULT32_32_Q31(xx,yy));
440 sh = celt_ilog2(x2y2)>>1;
441 t = VSHR32(x2y2, 2*(sh-7));
442 g = g0 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1);
443 }
444 #else
445 g = g0 = xy/celt_sqrt(1+xx*yy);
446 #endif
447 /* Look for any pitch at T/k */
448 for (k=2;k<=15;k++)
449 {
450 int T1, T1b;
451 opus_val16 g1;
452 opus_val16 cont=0;
453 opus_val16 thresh;
454 T1 = (2*T0+k)/(2*k);
455 if (T1 < minperiod)
456 break;
457 /* Look for another strong correlation at T1b */
458 if (k==2)
459 {
460 if (T1+T0>maxperiod)
461 T1b = T0;
462 else
463 T1b = T0+T1;
464 } else
465 {
466 T1b = (2*second_check[k]*T0+k)/(2*k);
467 }
468 dual_inner_prod(x, &x[-T1], &x[-T1b], N, &xy, &xy2);
469 xy += xy2;
470 yy = yy_lookup[T1] + yy_lookup[T1b];
471 #ifdef FIXED_POINT
472 {
473 opus_val32 x2y2;
474 int sh, t;
475 x2y2 = 1+MULT32_32_Q31(xx,yy);
476 sh = celt_ilog2(x2y2)>>1;
477 t = VSHR32(x2y2, 2*(sh-7));
478 g1 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1);
479 }
480 #else
481 g1 = xy/celt_sqrt(1+2.f*xx*1.f*yy);
482 #endif
483 if (abs(T1-prev_period)<=1)
484 cont = prev_gain;
485 else if (abs(T1-prev_period)<=2 && 5*k*k < T0)
486 cont = HALF32(prev_gain);
487 else
488 cont = 0;
489 thresh = MAX16(QCONST16(.3f,15), MULT16_16_Q15(QCONST16(.7f,15),g0)-cont);
490 /* Bias against very high pitch (very short period) to avoid false-positives
491 due to short-term correlation */
492 if (T1<3*minperiod)
493 thresh = MAX16(QCONST16(.4f,15), MULT16_16_Q15(QCONST16(.85f,15),g0)-cont);
494 else if (T1<2*minperiod)
495 thresh = MAX16(QCONST16(.5f,15), MULT16_16_Q15(QCONST16(.9f,15),g0)-cont);
496 if (g1 > thresh)
497 {
498 best_xy = xy;
499 best_yy = yy;
500 T = T1;
501 g = g1;
502 }
503 }
504 best_xy = MAX32(0, best_xy);
505 if (best_yy <= best_xy)
506 pg = Q15ONE;
507 else
508 pg = SHR32(frac_div32(best_xy,best_yy+1),16);
509
510 for (k=0;k<3;k++)
511 {
512 int T1 = T+k-1;
513 xy = 0;
514 for (i=0;i<N;i++)
515 xy = MAC16_16(xy, x[i], x[i-T1]);
516 xcorr[k] = xy;
517 }
518 if ((xcorr[2]-xcorr[0]) > MULT16_32_Q15(QCONST16(.7f,15),xcorr[1]-xcorr[0]))
519 offset = 1;
520 else if ((xcorr[0]-xcorr[2]) > MULT16_32_Q15(QCONST16(.7f,15),xcorr[1]-xcorr[2]))
521 offset = -1;
522 else
523 offset = 0;
524 if (pg > g)
525 pg = g;
526 *T0_ = 2*T+offset;
527
528 if (*T0_<minperiod0)
529 *T0_=minperiod0;
530 RESTORE_STACK;
531 return pg;
532 }
533