SphinxBase 5prealpha
yin.c
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1/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
2/*
3 * Copyright (c) 2008 Beyond Access, Inc. All rights reserved.
4 *
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6 * modification, are permitted provided that the following conditions
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14 * the documentation and/or other materials provided with the
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29
35/* This implements part of the YIN algorithm:
36 *
37 * "YIN, a fundamental frequency estimator for speech and music".
38 * Alain de Cheveigné and Hideki Kawahara. Journal of the Acoustical
39 * Society of America, 111 (4), April 2002.
40 */
41
44#include "sphinxbase/fixpoint.h"
45
46#include "sphinxbase/yin.h"
47
48#include <stdio.h>
49#include <string.h>
50
51struct yin_s {
52 uint16 frame_size;
54 uint16 search_range;
55 uint16 nfr;
57 unsigned char wsize;
58 unsigned char wstart;
59 unsigned char wcur;
60 unsigned char endut;
62 fixed32 **diff_window;
63 uint16 *period_window;
64};
65
69static void
70cmn_diff(int16 const *signal, int32 *out_diff, int ndiff)
71{
72 uint32 cum, cshift;
73 int32 t, tscale;
74
75 out_diff[0] = 32768;
76 cum = 0;
77 cshift = 0;
78
79 /* Determine how many bits we can scale t up by below. */
80 for (tscale = 0; tscale < 32; ++tscale)
81 if (ndiff & (1<<(31-tscale)))
82 break;
83 --tscale; /* Avoid teh overflowz. */
84 /* printf("tscale is %d (ndiff - 1) << tscale is %d\n",
85 tscale, (ndiff-1) << tscale); */
86
87 /* Somewhat elaborate block floating point implementation.
88 * The fp implementation of this is really a lot simpler. */
89 for (t = 1; t < ndiff; ++t) {
90 uint32 dd, dshift, norm;
91 int j;
92
93 dd = 0;
94 dshift = 0;
95 for (j = 0; j < ndiff; ++j) {
96 int diff = signal[j] - signal[t + j];
97 /* Guard against overflows. */
98 if (dd > (1UL<<tscale)) {
99 dd >>= 1;
100 ++dshift;
101 }
102 dd += (diff * diff) >> dshift;
103 }
104 /* Make sure the diffs and cum are shifted to the same
105 * scaling factor (usually dshift will be zero) */
106 if (dshift > cshift) {
107 cum += dd << (dshift-cshift);
108 }
109 else {
110 cum += dd >> (cshift-dshift);
111 }
112
113 /* Guard against overflows and also ensure that (t<<tscale) > cum. */
114 while (cum > (1UL<<tscale)) {
115 cum >>= 1;
116 ++cshift;
117 }
118 /* Avoid divide-by-zero! */
119 if (cum == 0) cum = 1;
120 /* Calculate the normalizer in high precision. */
121 norm = (t << tscale) / cum;
122 /* Do a long multiply and shift down to Q15. */
123 out_diff[t] = (int32)(((long long)dd * norm)
124 >> (tscale - 15 + cshift - dshift));
125 /* printf("dd %d cshift %d dshift %d scaledt %d cum %d norm %d cmn %d\n",
126 dd, cshift, dshift, (t<<tscale), cum, norm, out_diff[t]); */
127 }
128}
129
130yin_t *
131yin_init(int frame_size, float search_threshold,
132 float search_range, int smooth_window)
133{
134 yin_t *pe;
135
136 pe = ckd_calloc(1, sizeof(*pe));
137 pe->frame_size = frame_size;
138 pe->search_threshold = (uint16)(search_threshold * 32768);
139 pe->search_range = (uint16)(search_range * 32768);
140 pe->wsize = smooth_window * 2 + 1;
142 pe->frame_size / 2,
143 sizeof(**pe->diff_window));
145 sizeof(*pe->period_window));
146 return pe;
147}
148
149void
151{
154 ckd_free(pe);
155}
156
157void
159{
160 /* Reset the circular window pointers. */
161 pe->wstart = pe->endut = 0;
162 pe->nfr = 0;
163}
164
165void
167{
168 pe->endut = 1;
169}
170
171int
172thresholded_search(int32 *diff_window, fixed32 threshold, int start, int end)
173{
174 int i, min, argmin;
175
176 min = INT_MAX;
177 argmin = 0;
178 for (i = start; i < end; ++i) {
179 int diff = diff_window[i];
180
181 if (diff < threshold) {
182 min = diff;
183 argmin = i;
184 break;
185 }
186 if (diff < min) {
187 min = diff;
188 argmin = i;
189 }
190 }
191 return argmin;
192}
193
194void
195yin_write(yin_t *pe, int16 const *frame)
196{
197 int outptr, difflen;
198
199 /* Rotate the window one frame forward. */
200 ++pe->wstart;
201 /* Fill in the frame before wstart. */
202 outptr = pe->wstart - 1;
203 /* Wrap around the window pointer. */
204 if (pe->wstart == pe->wsize)
205 pe->wstart = 0;
206
207 /* Now calculate normalized difference function. */
208 difflen = pe->frame_size / 2;
209 cmn_diff(frame, pe->diff_window[outptr], difflen);
210
211 /* Find the first point under threshold. If not found, then
212 * use the absolute minimum. */
213 pe->period_window[outptr]
214 = thresholded_search(pe->diff_window[outptr],
215 pe->search_threshold, 0, difflen);
216
217 /* Increment total number of frames. */
218 ++pe->nfr;
219}
220
221int
222yin_read(yin_t *pe, uint16 *out_period, uint16 *out_bestdiff)
223{
224 int wstart, wlen, half_wsize, i;
225 int best, best_diff, search_width, low_period, high_period;
226
227 half_wsize = (pe->wsize-1)/2;
228 /* Without any smoothing, just return the current value (don't
229 * need to do anything to the current poitner either). */
230 if (half_wsize == 0) {
231 if (pe->endut)
232 return 0;
233 *out_period = pe->period_window[0];
234 *out_bestdiff = pe->diff_window[0][pe->period_window[0]];
235 return 1;
236 }
237
238 /* We can't do anything unless we have at least (wsize-1)/2 + 1
239 * frames, unless we're at the end of the utterance. */
240 if (pe->endut == 0 && pe->nfr < half_wsize + 1) {
241 /* Don't increment the current pointer either. */
242 return 0;
243 }
244
245 /* Establish the smoothing window. */
246 /* End of utterance. */
247 if (pe->endut) {
248 /* We are done (no more data) when pe->wcur = pe->wstart. */
249 if (pe->wcur == pe->wstart)
250 return 0;
251 /* I.e. pe->wcur (circular minus) half_wsize. */
252 wstart = (pe->wcur + pe->wsize - half_wsize) % pe->wsize;
253 /* Number of frames from wstart up to pe->wstart. */
254 wlen = pe->wstart - wstart;
255 if (wlen < 0) wlen += pe->wsize;
256 /*printf("ENDUT! ");*/
257 }
258 /* Beginning of utterance. */
259 else if (pe->nfr < pe->wsize) {
260 wstart = 0;
261 wlen = pe->nfr;
262 }
263 /* Normal case, it is what it is. */
264 else {
265 wstart = pe->wstart;
266 wlen = pe->wsize;
267 }
268
269 /* Now (finally) look for the best local estimate. */
270 /* printf("Searching for local estimate in %d frames around %d\n",
271 wlen, pe->nfr + 1 - wlen); */
272 best = pe->period_window[pe->wcur];
273 best_diff = pe->diff_window[pe->wcur][best];
274 for (i = 0; i < wlen; ++i) {
275 int j = wstart + i;
276 int diff;
277
278 j %= pe->wsize;
279 diff = pe->diff_window[j][pe->period_window[j]];
280 /* printf("%.2f,%.2f ", 1.0 - (double)diff/32768,
281 pe->period_window[j] ? 8000.0/pe->period_window[j] : 8000.0); */
282 if (diff < best_diff) {
283 best_diff = diff;
284 best = pe->period_window[j];
285 }
286 }
287 /* printf("best: %.2f, %.2f\n", 1.0 - (double)best_diff/32768,
288 best ? 8000.0/best : 8000.0); */
289 /* If it's the same as the current one then return it. */
290 if (best == pe->period_window[pe->wcur]) {
291 /* Increment the current pointer. */
292 if (++pe->wcur == pe->wsize)
293 pe->wcur = 0;
294 *out_period = best;
295 *out_bestdiff = best_diff;
296 return 1;
297 }
298 /* Otherwise, redo the search inside a narrower range. */
299 search_width = best * pe->search_range / 32768;
300 /* printf("Search width = %d * %.2f = %d\n",
301 best, (double)pe->search_range/32768, search_width); */
302 if (search_width == 0) search_width = 1;
303 low_period = best - search_width;
304 high_period = best + search_width;
305 if (low_period < 0) low_period = 0;
306 if (high_period > pe->frame_size / 2) high_period = pe->frame_size / 2;
307 /* printf("Searching from %d to %d\n", low_period, high_period); */
308 best = thresholded_search(pe->diff_window[pe->wcur],
310 low_period, high_period);
311 best_diff = pe->diff_window[pe->wcur][best];
312
313 if (out_period)
314 *out_period = (best > 32768) ? 32768 : best;
315 if (out_bestdiff)
316 *out_bestdiff = (best_diff > 32768) ? 32768 : best_diff;
317
318 /* Increment the current pointer. */
319 if (++pe->wcur == pe->wsize)
320 pe->wcur = 0;
321 return 1;
322}
Sphinx's memory allocation/deallocation routines.
SPHINXBASE_EXPORT void ckd_free(void *ptr)
Test and free a 1-D array.
Definition: ckd_alloc.c:244
SPHINXBASE_EXPORT void ckd_free_2d(void *ptr)
Free a 2-D array (ptr) previously allocated by ckd_calloc_2d.
Definition: ckd_alloc.c:255
#define ckd_calloc_2d(d1, d2, sz)
Macro for ckd_calloc_2d
Definition: ckd_alloc.h:270
#define ckd_calloc(n, sz)
Macros to simplify the use of above functions.
Definition: ckd_alloc.h:248
Basic type definitions used in Sphinx.
Definition: yin.c:51
unsigned char wsize
Size of smoothing window.
Definition: yin.c:57
unsigned char wstart
First frame in window.
Definition: yin.c:58
uint16 * period_window
Window of best period estimates.
Definition: yin.c:63
uint16 search_range
Range around best local estimate to search, in Q15.
Definition: yin.c:54
unsigned char endut
Hoch Hech! Are we at the utterance end?
Definition: yin.c:60
uint16 search_threshold
Size of analysis frame.
Definition: yin.c:53
fixed32 ** diff_window
Window of difference function outputs.
Definition: yin.c:62
unsigned char wcur
Current frame of analysis.
Definition: yin.c:59
uint16 nfr
Number of frames read so far.
Definition: yin.c:55
int yin_read(yin_t *pe, uint16 *out_period, uint16 *out_bestdiff)
Read a raw estimated pitch value from the pitch estimator.
Definition: yin.c:222
void yin_free(yin_t *pe)
Free a moving-window pitch estimator.
Definition: yin.c:150
void yin_end(yin_t *pe)
Mark the end of an utterance.
Definition: yin.c:166
yin_t * yin_init(int frame_size, float search_threshold, float search_range, int smooth_window)
Initialize moving-window pitch estimation.
Definition: yin.c:131
void yin_write(yin_t *pe, int16 const *frame)
Feed a frame of data to the pitch estimator.
Definition: yin.c:195
void yin_start(yin_t *pe)
Start processing an utterance.
Definition: yin.c:158
Implementation of pitch estimation.