7  * - stretch factor f
8  * - window size w
9  * - input step i
11  * - steady state of window s, ss = s*w
32    * FIXME: maybe shift could be allowed > 1.0 with factor < 1.0 ???
34   double factor;   /* strech factor. 1.0 means copy. */  member
52   double * fade_coefs;   /* fading, 1.0 -> 0.0 */
61   priv_t * p = (priv_t *) effp->priv;  in getopts()
62   --argc, ++argv;  in getopts()
65   p->factor = 1.0; /* default is no change */  in getopts()
66   p->window = DEFAULT_STRETCH_WINDOW;  in getopts()
68   if (argc > 0 && !sscanf(argv[0], "%lf", &p->factor)) {  in getopts()
69     lsx_fail("error while parsing factor");  in getopts()
73   if (argc > 1 && !sscanf(argv[1], "%lf", &p->window)) {  in getopts()
90   p->shift = (p->factor <= 1.0) ?  in getopts()
93   if (argc > 3 && !sscanf(argv[3], "%lf", &p->shift)) {  in getopts()
98   if (p->shift > 1.0 || p->shift <= 0.0) {  in getopts()
104      it makes sense for factor >= 0.5 */  in getopts()
105   if (p->factor < 1.0)  in getopts()
106     p->fading = 1.0 - (p->factor * p->shift);  in getopts()
108     p->fading = 1.0 - p->shift;  in getopts()
109   if (p->fading > 0.5)  in getopts()
110     p->fading = 0.5;  in getopts()
112   if (argc > 4 && !sscanf(argv[4], "%lf", &p->fading)) {  in getopts()
117   if (p->fading > 0.5 || p->fading < 0.0) {  in getopts()
130   priv_t * p = (priv_t *)effp->priv;  in start()
133   if (p->factor == 1)  in start()
136   p->state = input_state;  in start()
138   p->segment = (int)(effp->out_signal.rate * 0.001 * p->window);  in start()
140   p->index = p->segment / 2;  in start()
141   p->ibuf = lsx_malloc(p->segment * sizeof(sox_sample_t));  in start()
145   if (p->factor < 1.0) {  in start()
146     p->ishift = p->shift * p->segment;  in start()
147     p->oshift = p->factor * p->ishift;  in start()
149     p->oshift = p->shift * p->segment;  in start()
150     p->ishift = p->oshift / p->factor;  in start()
152   assert(p->ishift <= p->segment);  in start()
153   assert(p->oshift <= p->segment);  in start()
155   p->oindex = p->index; /* start as synchronized */  in start()
156   p->obuf = lsx_malloc(p->segment * sizeof(double));  in start()
157   p->overlap = (int)(p->fading * p->segment);  in start()
158   p->fade_coefs = lsx_malloc(p->overlap * sizeof(double));  in start()
161   for (i = 0; i<p->segment; i++)  in start()
162     p->ibuf[i] = 0;  in start()
164   for (i = 0; i<p->segment; i++)  in start()
165     p->obuf[i] = 0.0;  in start()
167   if (p->overlap>1) {  in start()
168     double slope = 1.0 / (p->overlap - 1);  in start()
169     p->fade_coefs[0] = 1.0;  in start()
170     for (i = 1; i < p->overlap - 1; i++)  in start()
171       p->fade_coefs[i] = slope * (p->overlap - i - 1);  in start()
172     p->fade_coefs[p->overlap - 1] = 0.0;  in start()
173   } else if (p->overlap == 1)  in start()
174     p->fade_coefs[0] = 1.0;  in start()
176   lsx_debug("start: (factor=%g segment=%g shift=%g overlap=%g)\nstate=%d\n"  in start()
177       "segment=%" PRIuPTR "\nindex=%" PRIuPTR "\n"  in start()
178       "ishift=%" PRIuPTR "\noindex=%" PRIuPTR "\n"  in start()
180       p->factor, p->window, p->shift, p->fading, p->state,  in start()
181       p->segment, p->index, p->ishift, p->oindex, p->oshift, p->overlap);  in start()
183   effp->out_signal.length = SOX_UNKNOWN_LEN; /* TODO: calculate actual length */  in start()
193   for (i = 0; i < p->overlap; i++)  in combine()
194     p->obuf[i] += p->fade_coefs[p->overlap - 1 - i] * p->ibuf[i];  in combine()
197   for (; i < p->segment - p->overlap; i++)  in combine()
198     p->obuf[i] += p->ibuf[i];  in combine()
201   for (; i<p->segment; i++)  in combine()
202     p->obuf[i] += p->fade_coefs[i - p->segment + p->overlap] * p->ibuf[i];  in combine()
211   priv_t * p = (priv_t *) effp->priv;  in flow()
216     if (p->state == input_state) {  in flow()
217       size_t tocopy = min(*isamp-iindex,  in flow()
218                              p->segment-p->index);  in flow()
220       memcpy(p->ibuf + p->index, ibuf + iindex, tocopy * sizeof(sox_sample_t));  in flow()
223       p->index += tocopy;  in flow()
225       if (p->index == p->segment) {  in flow()
230         for (i = 0; i + p->ishift < p->segment; i++)  in flow()
231           p->ibuf[i] = p->ibuf[i+p->ishift];  in flow()
233         p->index -= p->ishift;  in flow()
236         p->state = output_state;  in flow()
240     if (p->state == output_state) {  in flow()
241       while (p->oindex < p->oshift && oindex < *osamp) {  in flow()
243         f = p->obuf[p->oindex++];  in flow()
244         SOX_SAMPLE_CLIP_COUNT(f, effp->clips);  in flow()
248       if (p->oindex >= p->oshift && oindex<*osamp) {  in flow()
249         p->oindex -= p->oshift;  in flow()
252         for (i = 0; i + p->oshift < p->segment; i++)  in flow()
253           p->obuf[i] = p->obuf[i + p->oshift];  in flow()
256         for (; i < p->segment; i++)  in flow()
257           p->obuf[i] = 0.0;  in flow()
259         p->state = input_state;  in flow()
277   priv_t * p = (priv_t *) effp->priv;  in drain()
281   if (p->state == input_state) {  in drain()
282     for (i=p->index; i<p->segment; i++)  in drain()
283       p->ibuf[i] = 0;  in drain()
287     p->state = output_state;  in drain()
290   while (oindex<*osamp && p->oindex<p->index) {  in drain()
291     float f = p->obuf[p->oindex++];  in drain()
292     SOX_SAMPLE_CLIP_COUNT(f, effp->clips);  in drain()
298   if (p->oindex == p->index)  in drain()
307   priv_t * p = (priv_t *) effp->priv;  in stop()
309   free(p->ibuf);  in stop()
310   free(p->obuf);  in stop()
311   free(p->fade_coefs);  in stop()
319     "factor [window fade shift fading]\n"  in lsx_stretch_effect_fn()
320     "       (expansion, frame in ms, lin/..., unit<1.0, unit<0.5)\n"  in lsx_stretch_effect_fn()