src/tempo.c

   1 /* libSoX effect: change tempo (and duration) or pitch (maintain duration)
   2  * Copyright (c) 2007,8 robs@users.sourceforge.net
   3  * Based on ideas from Olli Parviainen's SoundTouch Library.
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Lesser General Public License as published by
   7  * the Free Software Foundation; either version 2.1 of the License, or (at
   8  * your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public License
  16  * along with this library; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  18  */
  19
  20 #include "sox_i.h"
  21 #include "fifo.h"
  22 #include <math.h>
  23
  24 typedef struct {
  25   /* Configuration parameters: */
  26   size_t channels;
  27   sox_bool quick_search; /* Whether to quick search or linear search */
  28   double factor;         /* 1 for no change, < 1 for slower, > 1 for faster. */
  29   size_t search;         /* Wide samples to search for best overlap position */
  30   size_t segment;        /* Processing segment length in wide samples */
  31   size_t overlap;        /* In wide samples */
  32
  33   size_t process_size;   /* # input wide samples needed to process 1 segment */
  34
  35   /* Buffers: */
  36   fifo_t input_fifo;
  37   float * overlap_buf;
  38   fifo_t output_fifo;
  39
  40   /* Counters: */
  41   uint64_t samples_in;
  42   uint64_t samples_out;
  43   uint64_t segments_total;
  44   uint64_t skip_total;
  45 } tempo_t;
  46
  47 /* Waveform Similarity by least squares; works across multi-channels */
  48 static float difference(const float * a, const float * b, size_t length)
  49 {
  50   float diff = 0;
  51   size_t i = 0;
  52
  53   #define _ diff += sqr(a[i] - b[i]), ++i; /* Loop optimisation */
  54   do {_ _ _ _ _ _ _ _} while (i < length); /* N.B. length ≡ 0 (mod 8) */
  55   #undef _
  56   return diff;
  57 }
  58
  59 /* Find where the two segments are most alike over the overlap period. */
  60 static size_t tempo_best_overlap_position(tempo_t * t, float const * new_win)
  61 {
  62   float * f = t->overlap_buf;
  63   size_t j, best_pos, prev_best_pos = (t->search + 1) >> 1, step = 64;
  64   size_t i = best_pos = t->quick_search? prev_best_pos : 0;
  65   float diff, least_diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
  66   int k = 0;
  67
  68   if (t->quick_search) do { /* hierarchical search */
  69     for (k = -1; k <= 1; k += 2) for (j = 1; j < 4 || step == 64; ++j) {
  70       i = prev_best_pos + k * j * step;
  71       if ((int)i < 0 || i >= t->search)
  72         break;
  73       diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
  74       if (diff < least_diff)
  75         least_diff = diff, best_pos = i;
  76     }
  77     prev_best_pos = best_pos;
  78   } while (step >>= 2);
  79   else for (i = 1; i < t->search; i++) { /* linear search */
  80     diff = difference(new_win + t->channels * i, f, t->channels * t->overlap);
  81     if (diff < least_diff)
  82       least_diff = diff, best_pos = i;
  83   }
  84   return best_pos;
  85 }
  86
  87 static void tempo_overlap(
  88     tempo_t * t, const float * in1, const float * in2, float * output)
  89 {
  90   size_t i, j, k = 0;
  91   float fade_step = 1.0f / (float) t->overlap;
  92
  93   for (i = 0; i < t->overlap; ++i) {
  94     float fade_in  = fade_step * (float) i;
  95     float fade_out = 1.0f - fade_in;
  96     for (j = 0; j < t->channels; ++j, ++k)
  97       output[k] = in1[k] * fade_out + in2[k] * fade_in;
  98   }
  99 }
 100
 101 static void tempo_process(tempo_t * t)
 102 {
 103   while (fifo_occupancy(&t->input_fifo) >= t->process_size) {
 104     size_t skip, offset;
 105
 106     /* Copy or overlap the first bit to the output */
 107     if (!t->segments_total) {
 108       offset = t->search / 2;
 109       fifo_write(&t->output_fifo, t->overlap, (float *) fifo_read_ptr(&t->input_fifo) + t->channels * offset);
 110     } else {
 111       offset = tempo_best_overlap_position(t, fifo_read_ptr(&t->input_fifo));
 112       tempo_overlap(t, t->overlap_buf,
 113           (float *) fifo_read_ptr(&t->input_fifo) + t->channels * offset,
 114           fifo_write(&t->output_fifo, t->overlap, NULL));
 115     }
 116     /* Copy the middle bit to the output */
 117     fifo_write(&t->output_fifo, t->segment - 2 * t->overlap,
 118                (float *) fifo_read_ptr(&t->input_fifo) +
 119                t->channels * (offset + t->overlap));
 120
 121     /* Copy the end bit to overlap_buf ready to be mixed with
 122      * the beginning of the next segment. */
 123     memcpy(t->overlap_buf,
 124            (float *) fifo_read_ptr(&t->input_fifo) +
 125            t->channels * (offset + t->segment - t->overlap),
 126            t->channels * t->overlap * sizeof(*(t->overlap_buf)));
 127
 128     /* Advance through the input stream */
 129     skip = t->factor * (++t->segments_total * (t->segment - t->overlap)) + 0.5;
 130     t->skip_total += skip -= t->skip_total;
 131     fifo_read(&t->input_fifo, skip, NULL);
 132   }
 133 }
 134
 135 static float * tempo_input(tempo_t * t, float const * samples, size_t n)
 136 {
 137   t->samples_in += n;
 138   return fifo_write(&t->input_fifo, n, samples);
 139 }
 140
 141 static float const * tempo_output(tempo_t * t, float * samples, size_t * n)
 142 {
 143   t->samples_out += *n = min(*n, fifo_occupancy(&t->output_fifo));
 144   return fifo_read(&t->output_fifo, *n, samples);
 145 }
 146
 147 /* Flush samples remaining in overlap_buf & input_fifo to the output. */
 148 static void tempo_flush(tempo_t * t)
 149 {
 150   uint64_t samples_out = t->samples_in / t->factor + .5;
 151   size_t remaining = samples_out > t->samples_out ?
 152       (size_t)(samples_out - t->samples_out) : 0;
 153   float * buff = lsx_calloc(128 * t->channels, sizeof(*buff));
 154
 155   if (remaining > 0) {
 156     while (fifo_occupancy(&t->output_fifo) < remaining) {
 157       tempo_input(t, buff, (size_t) 128);
 158       tempo_process(t);
 159     }
 160     fifo_trim_to(&t->output_fifo, remaining);
 161     t->samples_in = 0;
 162   }
 163   free(buff);
 164 }
 165
 166 static void tempo_setup(tempo_t * t,
 167   double sample_rate, sox_bool quick_search, double factor,
 168   double segment_ms, double search_ms, double overlap_ms)
 169 {
 170   size_t max_skip;
 171   t->quick_search = quick_search;
 172   t->factor = factor;
 173   t->segment = sample_rate * segment_ms / 1000 + .5;
 174   t->search  = sample_rate * search_ms / 1000 + .5;
 175   t->overlap = max(sample_rate * overlap_ms / 1000 + 4.5, 16);
 176   t->overlap &= ~7; /* Make divisible by 8 for loop optimisation */
 177   if (t->overlap * 2 > t->segment)
 178     t->overlap -= 8;
 179   t->overlap_buf = lsx_malloc(t->overlap * t->channels * sizeof(*t->overlap_buf));
 180   max_skip = ceil(factor * (t->segment - t->overlap));
 181   t->process_size = max(max_skip + t->overlap, t->segment) + t->search;
 182   memset(fifo_reserve(&t->input_fifo, t->search / 2), 0, (t->search / 2) * t->channels * sizeof(float));
 183 }
 184
 185 static void tempo_delete(tempo_t * t)
 186 {
 187   free(t->overlap_buf);
 188   fifo_delete(&t->output_fifo);
 189   fifo_delete(&t->input_fifo);
 190   free(t);
 191 }
 192
 193 static tempo_t * tempo_create(size_t channels)
 194 {
 195   tempo_t * t = lsx_calloc(1, sizeof(*t));
 196   t->channels = channels;
 197   fifo_create(&t->input_fifo, t->channels * sizeof(float));
 198   fifo_create(&t->output_fifo, t->channels * sizeof(float));
 199   return t;
 200 }
 201
 202 /*------------------------------- SoX Wrapper --------------------------------*/
 203
 204 typedef struct {
 205   tempo_t     * tempo;
 206   sox_bool    quick_search;
 207   double      factor, segment_ms, search_ms, overlap_ms;
 208 } priv_t;
 209
 210 static int getopts(sox_effect_t * effp, int argc, char **argv)
 211 {
 212   priv_t * p = (priv_t *)effp->priv;
 213   enum {Default, Music, Speech, Linear} profile = Default;
 214   static const double segments_ms [] = {   82,82,  35  , 20};
 215   static const double segments_pow[] = {    0, 1, .33  , 1};
 216   static const double overlaps_div[] = {6.833, 7,  2.5 , 2};
 217   static const double searches_div[] = {5.587, 6,  2.14, 2};
 218   int c;
 219   lsx_getopt_t optstate;
 220   lsx_getopt_init(argc, argv, "+qmls", NULL, lsx_getopt_flag_none, 1, &optstate);
 221
 222   p->segment_ms = p->search_ms = p->overlap_ms = HUGE_VAL;
 223   while ((c = lsx_getopt(&optstate)) != -1) switch (c) {
 224     case 'q': p->quick_search  = sox_true;   break;
 225     case 'm': profile = Music; break;
 226     case 's': profile = Speech; break;
 227     case 'l': profile = Linear; p->search_ms = 0; break;
 228     default: lsx_fail("unknown option `-%c'", optstate.opt); return lsx_usage(effp);
 229   }
 230   argc -= optstate.ind, argv += optstate.ind;
 231   do {                    /* break-able block */
 232     NUMERIC_PARAMETER(factor      ,0.1 , 100 )
 233     NUMERIC_PARAMETER(segment_ms  , 10 , 120)
 234     NUMERIC_PARAMETER(search_ms   , 0  , 30 )
 235     NUMERIC_PARAMETER(overlap_ms  , 0  , 30 )
 236   } while (0);
 237
 238   if (p->segment_ms == HUGE_VAL)
 239     p->segment_ms = max(10, segments_ms[profile] / max(pow(p->factor, segments_pow[profile]), 1));
 240   if (p->overlap_ms == HUGE_VAL)
 241     p->overlap_ms = p->segment_ms / overlaps_div[profile];
 242   if (p->search_ms == HUGE_VAL)
 243     p->search_ms = p->segment_ms / searches_div[profile];
 244
 245   p->overlap_ms = min(p->overlap_ms, p->segment_ms / 2);
 246   lsx_report("quick_search=%u factor=%g segment=%g search=%g overlap=%g",
 247     p->quick_search, p->factor, p->segment_ms, p->search_ms, p->overlap_ms);
 248   return argc? lsx_usage(effp) : SOX_SUCCESS;
 249 }
 250
 251 static int start(sox_effect_t * effp)
 252 {
 253   priv_t * p = (priv_t *)effp->priv;
 254
 255   if (p->factor == 1)
 256     return SOX_EFF_NULL;
 257
 258   p->tempo = tempo_create((size_t)effp->in_signal.channels);
 259   tempo_setup(p->tempo, effp->in_signal.rate, p->quick_search, p->factor,
 260       p->segment_ms, p->search_ms, p->overlap_ms);
 261
 262   effp->out_signal.length = SOX_UNKNOWN_LEN;
 263   if (effp->in_signal.length != SOX_UNKNOWN_LEN) {
 264     uint64_t in_length = effp->in_signal.length / effp->in_signal.channels;
 265     uint64_t out_length = in_length / p->factor + .5;
 266     effp->out_signal.length = out_length * effp->in_signal.channels;
 267   }
 268
 269   return SOX_SUCCESS;
 270 }
 271
 272 static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
 273                 sox_sample_t * obuf, size_t * isamp, size_t * osamp)
 274 {
 275   priv_t * p = (priv_t *)effp->priv;
 276   size_t i, odone = *osamp /= effp->in_signal.channels;
 277   float const * s = tempo_output(p->tempo, NULL, &odone);
 278   SOX_SAMPLE_LOCALS;
 279
 280   for (i = 0; i < odone * effp->in_signal.channels; ++i)
 281     *obuf++ = SOX_FLOAT_32BIT_TO_SAMPLE(*s++, effp->clips);
 282
 283   if (*isamp && odone < *osamp) {
 284     float * t = tempo_input(p->tempo, NULL, *isamp / effp->in_signal.channels);
 285     for (i = *isamp; i; --i)
 286       *t++ = SOX_SAMPLE_TO_FLOAT_32BIT(*ibuf++, effp->clips);
 287     tempo_process(p->tempo);
 288   }
 289   else *isamp = 0;
 290
 291   *osamp = odone * effp->in_signal.channels;
 292   return SOX_SUCCESS;
 293 }
 294
 295 static int drain(sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp)
 296 {
 297   priv_t * p = (priv_t *)effp->priv;
 298   static size_t isamp = 0;
 299   tempo_flush(p->tempo);
 300   return flow(effp, 0, obuf, &isamp, osamp);
 301 }
 302
 303 static int stop(sox_effect_t * effp)
 304 {
 305   priv_t * p = (priv_t *)effp->priv;
 306   tempo_delete(p->tempo);
 307   return SOX_SUCCESS;
 308 }
 309
 310 sox_effect_handler_t const * lsx_tempo_effect_fn(void)
 311 {
 312   static sox_effect_handler_t handler = {
 313     "tempo", "[-q] [-m | -s | -l] factor [segment-ms [search-ms [overlap-ms]]]",
 314     SOX_EFF_MCHAN | SOX_EFF_LENGTH,
 315     getopts, start, flow, drain, stop, NULL, sizeof(priv_t)
 316   };
 317   return &handler;
 318 }
 319
 320 /*---------------------------------- pitch -----------------------------------*/
 321
 322 static int pitch_getopts(sox_effect_t * effp, int argc, char **argv)
 323 {
 324   double d;
 325   char dummy, arg[100], **argv2 = lsx_malloc(argc * sizeof(*argv2));
 326   int result, pos = (argc > 1 && !strcmp(argv[1], "-q"))? 2 : 1;
 327
 328   if (argc <= pos || sscanf(argv[pos], "%lf %c", &d, &dummy) != 1)
 329     return lsx_usage(effp);
 330
 331   d = pow(2., d / 1200);  /* cents --> factor */
 332   sprintf(arg, "%g", 1 / d);
 333   memcpy(argv2, argv, argc * sizeof(*argv2));
 334   argv2[pos] = arg;
 335   result = getopts(effp, argc, argv2);
 336   free(argv2);
 337   return result;
 338 }
 339
 340 static int pitch_start(sox_effect_t * effp)
 341 {
 342   priv_t * p = (priv_t *) effp->priv;
 343   int result = start(effp);
 344
 345   effp->out_signal.rate = effp->in_signal.rate / p->factor;
 346   return result;
 347 }
 348
 349 sox_effect_handler_t const * lsx_pitch_effect_fn(void)
 350 {
 351   static sox_effect_handler_t handler;
 352   handler = *lsx_tempo_effect_fn();
 353   handler.name = "pitch";
 354   handler.usage = "[-q] shift-in-cents [segment-ms [search-ms [overlap-ms]]]",
 355   handler.getopts = pitch_getopts;
 356   handler.start = pitch_start;
 357   handler.flags &= ~SOX_EFF_LENGTH;
 358   handler.flags |= SOX_EFF_RATE;
 359   return &handler;
 360 }