ref: db11a831b5188094f926527ba4b72eca392f9ecb
dir: /src/rate.c/
/* Effect: change sample rate Copyright (c) 2008 robs@users.sourceforge.net * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at * your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /* Inspired by, and builds upon some of the ideas presented in: * `The Quest For The Perfect Resampler' by Laurent De Soras; * http://ldesoras.free.fr/doc/articles/resampler-en.pdf */ #ifdef NDEBUG /* Enable assert always. */ #undef NDEBUG /* Must undef above assert.h or other that might include it. */ #endif #include "sox_i.h" #include "fft4g.h" #include "dft_filter.h" #include <assert.h> #include <string.h> #define calloc lsx_calloc #define malloc lsx_malloc #define raw_coef_t double #define sample_t double #define TO_SOX SOX_FLOAT_64BIT_TO_SAMPLE #define FROM_SOX SOX_SAMPLE_TO_FLOAT_64BIT #define coef(coef_p, interp_order, fir_len, phase_num, coef_interp_num, fir_coef_num) coef_p[(fir_len) * ((interp_order) + 1) * (phase_num) + ((interp_order) + 1) * (fir_coef_num) + (interp_order - coef_interp_num)] static sample_t * prepare_coefs(raw_coef_t const * coefs, int num_coefs, int num_phases, int interp_order, int multiplier) { int i, j, length = num_coefs * num_phases; sample_t * result = malloc(length * (interp_order + 1) * sizeof(*result)); double fm1 = coefs[0], f1 = 0, f2 = 0; for (i = num_coefs - 1; i >= 0; --i) for (j = num_phases - 1; j >= 0; --j) { double f0 = fm1, b = 0, c = 0, d = 0; /* = 0 to kill compiler warning */ int pos = i * num_phases + j - 1; fm1 = (pos > 0 ? coefs[pos - 1] : 0) * multiplier; switch (interp_order) { case 1: b = f1 - f0; break; case 2: b = f1 - (.5 * (f2+f0) - f1) - f0; c = .5 * (f2+f0) - f1; break; case 3: c=.5*(f1+fm1)-f0;d=(1/6.)*(f2-f1+fm1-f0-4*c);b=f1-f0-d-c; break; default: if (interp_order) assert(0); } #define coef_coef(x) \ coef(result, interp_order, num_coefs, j, x, num_coefs - 1 - i) coef_coef(0) = f0; if (interp_order > 0) coef_coef(1) = b; if (interp_order > 1) coef_coef(2) = c; if (interp_order > 2) coef_coef(3) = d; #undef coef_coef f2 = f1, f1 = f0; } return result; } typedef struct { /* Data that are shared between channels and filters */ sample_t * poly_fir_coefs; dft_filter_t half_band[2]; /* [0]: halve; [1]: down/up: halve/double */ } rate_shared_t; struct stage; typedef void (* stage_fn_t)(struct stage * input, fifo_t * output); typedef struct stage { rate_shared_t * shared; fifo_t fifo; int pre; /* Number of past samples to store */ int pre_post; /* pre + number of future samples to store */ int preload; /* Number of zero samples to pre-load the fifo */ int which; /* Which of the 2 half-band filters to use */ stage_fn_t fn; /* For poly_fir & spline: */ union { /* 32bit.32bit fixed point arithmetic */ #if defined(WORDS_BIGENDIAN) struct {int32_t integer; uint32_t fraction;} parts; #else struct {uint32_t fraction; int32_t integer;} parts; #endif int64_t all; #define MULT32 (65536. * 65536.) } at, step; int divisor; /* For step: > 1 for rational; 1 otherwise */ double out_in_ratio; } stage_t; #define stage_occupancy(s) max(0, fifo_occupancy(&(s)->fifo) - (s)->pre_post) #define stage_read_p(s) ((sample_t *)fifo_read_ptr(&(s)->fifo) + (s)->pre) static void cubic_spline(stage_t * p, fifo_t * output_fifo) { int i, num_in = stage_occupancy(p), max_num_out = 1 + num_in*p->out_in_ratio; sample_t const * input = stage_read_p(p); sample_t * output = fifo_reserve(output_fifo, max_num_out); for (i = 0; p->at.parts.integer < num_in; ++i, p->at.all += p->step.all) { sample_t const * s = input + p->at.parts.integer; sample_t x = p->at.parts.fraction * (1 / MULT32); sample_t b = .5*(s[1]+s[-1])-*s, a = (1/6.)*(s[2]-s[1]+s[-1]-*s-4*b); sample_t c = s[1]-*s-a-b; output[i] = ((a*x + b)*x + c)*x + *s; } assert(max_num_out - i >= 0); fifo_trim_by(output_fifo, max_num_out - i); fifo_read(&p->fifo, p->at.parts.integer, NULL); p->at.parts.integer = 0; } static void half_sample(stage_t * p, fifo_t * output_fifo) { sample_t * output; int i, j, num_in = max(0, fifo_occupancy(&p->fifo)); rate_shared_t const * s = p->shared; dft_filter_t const * f = &s->half_band[p->which]; int const overlap = f->num_taps - 1; while (num_in >= f->dft_length) { sample_t const * input = fifo_read_ptr(&p->fifo); fifo_read(&p->fifo, f->dft_length - overlap, NULL); num_in -= f->dft_length - overlap; output = fifo_reserve(output_fifo, f->dft_length); fifo_trim_by(output_fifo, (f->dft_length + overlap) >> 1); memcpy(output, input, f->dft_length * sizeof(*output)); lsx_safe_rdft(f->dft_length, 1, output); output[0] *= f->coefs[0]; output[1] *= f->coefs[1]; for (i = 2; i < f->dft_length; i += 2) { sample_t tmp = output[i]; output[i ] = f->coefs[i ] * tmp - f->coefs[i+1] * output[i+1]; output[i+1] = f->coefs[i+1] * tmp + f->coefs[i ] * output[i+1]; } lsx_safe_rdft(f->dft_length, -1, output); for (j = 1, i = 2; i < f->dft_length - overlap; ++j, i += 2) output[j] = output[i]; } } static void double_sample(stage_t * p, fifo_t * output_fifo) { sample_t * output; int i, j, num_in = max(0, fifo_occupancy(&p->fifo)); rate_shared_t const * s = p->shared; dft_filter_t const * f = &s->half_band[1]; int const overlap = f->num_taps - 1; while (num_in > f->dft_length >> 1) { sample_t const * input = fifo_read_ptr(&p->fifo); fifo_read(&p->fifo, (f->dft_length - overlap) >> 1, NULL); num_in -= (f->dft_length - overlap) >> 1; output = fifo_reserve(output_fifo, f->dft_length); fifo_trim_by(output_fifo, overlap); for (j = i = 0; i < f->dft_length; ++j, i += 2) output[i] = input[j], output[i+1] = 0; lsx_safe_rdft(f->dft_length, 1, output); output[0] *= f->coefs[0]; output[1] *= f->coefs[1]; for (i = 2; i < f->dft_length; i += 2) { sample_t tmp = output[i]; output[i ] = f->coefs[i ] * tmp - f->coefs[i+1] * output[i+1]; output[i+1] = f->coefs[i+1] * tmp + f->coefs[i ] * output[i+1]; } lsx_safe_rdft(f->dft_length, -1, output); } } static void half_band_filter_init(rate_shared_t * p, unsigned which, int num_taps, sample_t const h[], double Fp, double att, int multiplier, double phase, sox_bool allow_aliasing) { dft_filter_t * f = &p->half_band[which]; int dft_length, i; if (f->num_taps) return; if (h) { dft_length = lsx_set_dft_length(num_taps); f->coefs = calloc(dft_length, sizeof(*f->coefs)); for (i = 0; i < num_taps; ++i) f->coefs[(i + dft_length - num_taps + 1) & (dft_length - 1)] = h[abs(num_taps / 2 - i)] / dft_length * 2 * multiplier; f->post_peak = num_taps / 2; } else { double * h2 = lsx_design_lpf(Fp, 1., 2., allow_aliasing, att, &num_taps, 0); if (phase != 50) lsx_fir_to_phase(&h2, &num_taps, &f->post_peak, phase); else f->post_peak = num_taps / 2; dft_length = lsx_set_dft_length(num_taps); f->coefs = calloc(dft_length, sizeof(*f->coefs)); for (i = 0; i < num_taps; ++i) f->coefs[(i + dft_length - num_taps + 1) & (dft_length - 1)] = h2[i] / dft_length * 2 * multiplier; free(h2); } assert(num_taps & 1); f->num_taps = num_taps; f->dft_length = dft_length; lsx_debug("fir_len=%i dft_length=%i Fp=%g att=%g mult=%i", num_taps, dft_length, Fp, att, multiplier); lsx_safe_rdft(dft_length, 1, f->coefs); } #include "rate_filters.h" typedef struct { double factor; size_t samples_in, samples_out; int level, input_stage_num, output_stage_num; sox_bool upsample; stage_t * stages; } rate_t; #define pre_stage p->stages[-1] #define last_stage p->stages[p->level] #define post_stage p->stages[p->level + 1] typedef enum {Default = -1, Quick, Low, Medium, High, Very} quality_t; static void rate_init(rate_t * p, rate_shared_t * shared, double factor, quality_t quality, int interp_order, double phase, double bandwidth, sox_bool allow_aliasing) { int i, mult, divisor = 1; assert(factor > 0); p->factor = factor; if (quality < Quick || quality > Very) quality = High; if (quality != Quick) { const int max_divisor = 2048; /* Keep coef table size ~< 500kb */ const double epsilon = 4 / MULT32; /* Scaled to half this at max_divisor */ p->upsample = p->factor < 1; for (i = factor, p->level = 0; i >>= 1; ++p->level); /* log base 2 */ factor /= 1 << (p->level + !p->upsample); for (i = 2; i <= max_divisor && divisor == 1; ++i) { double try_d = factor * i; int try = try_d + .5; if (fabs(try - try_d) < try * epsilon * (1 - (.5 / max_divisor) * i)) { if (try == i) /* Rounded to 1:1? */ factor = 1, divisor = 2, p->upsample = sox_false; else factor = try, divisor = i; } } } p->stages = (stage_t *)calloc((size_t)p->level + 4, sizeof(*p->stages)) + 1; for (i = -1; i <= p->level + 1; ++i) p->stages[i].shared = shared; last_stage.step.all = factor * MULT32 + .5; last_stage.out_in_ratio = MULT32 * divisor / last_stage.step.all; if (divisor != 1) assert(!last_stage.step.parts.fraction); else if (quality != Quick) assert(!last_stage.step.parts.integer); lsx_debug("i/o=%g; %.9g:%i @ level %i", p->factor, factor, divisor, p->level); mult = 1 + p->upsample; /* Compensate for zero-stuffing in double_sample */ p->input_stage_num = -p->upsample; p->output_stage_num = p->level; if (quality == Quick) { ++p->output_stage_num; last_stage.fn = cubic_spline; last_stage.pre_post = max(3, last_stage.step.parts.integer); last_stage.preload = last_stage.pre = 1; } else if (last_stage.out_in_ratio != 2 || (p->upsample && quality == Low)) { poly_fir_t const * f; poly_fir1_t const * f1; int n = 4 * p->upsample + range_limit(quality, Medium, Very) - Medium; if (interp_order < 0) interp_order = quality > High; interp_order = divisor == 1? 1 + interp_order : 0; last_stage.divisor = divisor; p->output_stage_num += 2; if (p->upsample && quality == Low) mult = 1, ++p->input_stage_num, --p->output_stage_num, --n; f = &poly_firs[n]; f1 = &f->interp[interp_order]; if (!last_stage.shared->poly_fir_coefs) { int num_taps = 0, phases = divisor == 1? (1 << f1->phase_bits) : divisor; raw_coef_t * coefs = lsx_design_lpf( f->pass, f->stop, 1., sox_false, f->att, &num_taps, phases); assert(num_taps == f->num_coefs * phases - 1); last_stage.shared->poly_fir_coefs = prepare_coefs(coefs, f->num_coefs, phases, interp_order, mult); lsx_debug("fir_len=%i phases=%i coef_interp=%i mult=%i size=%s", f->num_coefs, phases, interp_order, mult, lsx_sigfigs3((num_taps +1.) * (interp_order + 1) * sizeof(sample_t))); free(coefs); } last_stage.fn = f1->fn; last_stage.pre_post = f->num_coefs - 1; last_stage.pre = 0; last_stage.preload = last_stage.pre_post >> 1; mult = 1; } if (quality > Low) { typedef struct {int len; sample_t const * h; double bw, a;} filter_t; static filter_t const filters[] = { {2 * array_length(half_fir_coefs_low) - 1, half_fir_coefs_low, 0,0}, {0, NULL, .931, 110}, {0, NULL, .931, 125}, {0, NULL, .931, 170}}; filter_t const * f = &filters[quality - Low]; double att = allow_aliasing? (34./33)* f->a : f->a; /* negate att degrade */ double bw = bandwidth? 1 - (1 - bandwidth / 100) / LSX_TO_3dB : f->bw; double min = 1 - (allow_aliasing? LSX_MAX_TBW0A : LSX_MAX_TBW0) / 100; assert((size_t)(quality - Low) < array_length(filters)); half_band_filter_init(shared, p->upsample, f->len, f->h, bw, att, mult, phase, allow_aliasing); if (p->upsample) { pre_stage.fn = double_sample; /* Finish off setting up pre-stage */ pre_stage.preload = shared->half_band[1].post_peak >> 1; /* Start setting up post-stage; TODO don't use dft for short filters */ if ((1 - p->factor) / (1 - bw) > 2) half_band_filter_init(shared, 0, 0, NULL, max(p->factor, min), att, 1, phase, allow_aliasing); else shared->half_band[0] = shared->half_band[1]; } else if (p->level > 0 && p->output_stage_num > p->level) { double pass = bw * divisor / factor / 2; if ((1 - pass) / (1 - bw) > 2) half_band_filter_init(shared, 1, 0, NULL, max(pass, min), att, 1, phase, allow_aliasing); } post_stage.fn = half_sample; post_stage.preload = shared->half_band[0].post_peak; } else if (quality == Low && !p->upsample) { /* dft is slower here, so */ post_stage.fn = half_sample_low; /* use normal convolution */ post_stage.pre_post = 2 * (array_length(half_fir_coefs_low) - 1); post_stage.preload = post_stage.pre = post_stage.pre_post >> 1; } if (p->level > 0) { stage_t * s = & p->stages[p->level - 1]; if (shared->half_band[1].num_taps) { s->fn = half_sample; s->preload = shared->half_band[1].post_peak; s->which = 1; } else *s = post_stage; } for (i = p->input_stage_num; i <= p->output_stage_num; ++i) { stage_t * s = &p->stages[i]; if (i >= 0 && i < p->level - 1) { s->fn = half_sample_25; s->pre_post = 2 * (array_length(half_fir_coefs_25) - 1); s->preload = s->pre = s->pre_post >> 1; } fifo_create(&s->fifo, (int)sizeof(sample_t)); memset(fifo_reserve(&s->fifo, s->preload), 0, sizeof(sample_t)*s->preload); if (i < p->output_stage_num) lsx_debug("stage=%-3ipre_post=%-3ipre=%-3ipreload=%i", i, s->pre_post, s->pre, s->preload); } } static void rate_process(rate_t * p) { stage_t * stage = p->stages + p->input_stage_num; int i; for (i = p->input_stage_num; i < p->output_stage_num; ++i, ++stage) stage->fn(stage, &(stage+1)->fifo); } static sample_t * rate_input(rate_t * p, sample_t const * samples, size_t n) { p->samples_in += n; return fifo_write(&p->stages[p->input_stage_num].fifo, (int)n, samples); } static sample_t const * rate_output(rate_t * p, sample_t * samples, size_t * n) { fifo_t * fifo = &p->stages[p->output_stage_num].fifo; p->samples_out += *n = min(*n, (size_t)fifo_occupancy(fifo)); return fifo_read(fifo, (int)*n, samples); } static void rate_flush(rate_t * p) { fifo_t * fifo = &p->stages[p->output_stage_num].fifo; size_t samples_out = p->samples_in / p->factor + .5; size_t remaining = samples_out - p->samples_out; sample_t * buff = calloc(1024, sizeof(*buff)); if ((int)remaining > 0) { while ((size_t)fifo_occupancy(fifo) < remaining) { rate_input(p, buff, (size_t) 1024); rate_process(p); } fifo_trim_to(fifo, (int)remaining); p->samples_in = 0; } free(buff); } static void rate_close(rate_t * p) { rate_shared_t * shared = p->stages[0].shared; int i; for (i = p->input_stage_num; i <= p->output_stage_num; ++i) fifo_delete(&p->stages[i].fifo); free(shared->half_band[0].coefs); if (shared->half_band[1].coefs != shared->half_band[0].coefs) free(shared->half_band[1].coefs); free(shared->poly_fir_coefs); memset(shared, 0, sizeof(*shared)); free(p->stages - 1); } /*------------------------------- SoX Wrapper --------------------------------*/ typedef struct { sox_rate_t out_rate; int quality; double coef_interp, phase, bandwidth; sox_bool allow_aliasing; rate_t rate; rate_shared_t shared, * shared_ptr; } priv_t; static int create(sox_effect_t * effp, int argc, char **argv) { priv_t * p = (priv_t *) effp->priv; int c; char * dummy_p, * found_at, * opts = "+i:b:p:MILasqlmhv", * qopts = opts +12; lsx_getopt_t optstate; lsx_getopt_init(argc, argv, opts, NULL, lsx_getopt_flag_none, 1, &optstate); p->quality = -1; p->phase = 50; p->shared_ptr = &p->shared; while ((c = lsx_getopt(&optstate)) != -1) switch (c) { GETOPT_NUMERIC(optstate, 'i', coef_interp, 1 , 3) GETOPT_NUMERIC(optstate, 'p', phase, 0 , 100) GETOPT_NUMERIC(optstate, 'b', bandwidth, 100 - LSX_MAX_TBW3, 99.7) case 'M': p->phase = 0; break; case 'I': p->phase = 25; break; case 'L': p->phase = 50; break; case 's': p->bandwidth = 99; break; case 'a': p->allow_aliasing = sox_true; break; default: if ((found_at = strchr(qopts, c))) p->quality = found_at - qopts; else {lsx_fail("unknown option `-%c'", optstate.opt); return lsx_usage(effp);} } argc -= optstate.ind, argv += optstate.ind; if ((unsigned)p->quality < 2 && (p->bandwidth || p->phase != 50 || p->allow_aliasing)) { lsx_fail("override options not allowed with this quality level"); return SOX_EOF; } if (p->bandwidth && p->bandwidth < 100 - LSX_MAX_TBW3A && p->allow_aliasing) { lsx_fail("minimum allowed bandwidth with aliasing is %g%%", 100 - LSX_MAX_TBW3A); return SOX_EOF; } if (argc) { if ((p->out_rate = lsx_parse_frequency(*argv, &dummy_p)) <= 0 || *dummy_p) return lsx_usage(effp); argc--; argv++; effp->out_signal.rate = p->out_rate; } return argc? lsx_usage(effp) : SOX_SUCCESS; } static int start(sox_effect_t * effp) { priv_t * p = (priv_t *) effp->priv; double out_rate = p->out_rate != 0 ? p->out_rate : effp->out_signal.rate; if (effp->in_signal.rate == out_rate) return SOX_EFF_NULL; if (effp->in_signal.mult) *effp->in_signal.mult *= .705; /* 1/(2/sinc(pi/3)-1); see De Soras 4.1.2 */ effp->out_signal.channels = effp->in_signal.channels; effp->out_signal.rate = out_rate; rate_init(&p->rate, p->shared_ptr, effp->in_signal.rate / out_rate, p->quality, (int)p->coef_interp - 1, p->phase, p->bandwidth, p->allow_aliasing); return SOX_SUCCESS; } static int flow(sox_effect_t * effp, const sox_sample_t * ibuf, sox_sample_t * obuf, size_t * isamp, size_t * osamp) { priv_t * p = (priv_t *)effp->priv; size_t i, odone = *osamp; SOX_SAMPLE_LOCALS; sample_t const * s = rate_output(&p->rate, NULL, &odone); for (i = 0; i < odone; ++i) *obuf++ = TO_SOX(*s++, effp->clips); if (*isamp && odone < *osamp) { sample_t * t = rate_input(&p->rate, NULL, *isamp); for (i = *isamp; i; --i) *t++ = FROM_SOX(*ibuf++,); rate_process(&p->rate); } else *isamp = 0; *osamp = odone; return SOX_SUCCESS; } static int drain(sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp) { priv_t * p = (priv_t *)effp->priv; static size_t isamp = 0; rate_flush(&p->rate); return flow(effp, 0, obuf, &isamp, osamp); } static int stop(sox_effect_t * effp) { priv_t * p = (priv_t *) effp->priv; rate_close(&p->rate); return SOX_SUCCESS; } sox_effect_handler_t const * lsx_rate_effect_fn(void) { static sox_effect_handler_t handler = { "rate", 0, SOX_EFF_RATE, create, start, flow, drain, stop, 0, sizeof(priv_t) }; static char const * lines[] = { "[-q|-l|-m|-h|-v] [override-options] RATE[k]", " BAND-", " QUALITY WIDTH REJ dB TYPICAL USE", " -q quick n/a ~30 @ Fs/4 playback on ancient hardware", " -l low 80% 100 playback on old hardware", " -m medium 95% 100 audio playback", " -h high (default) 95% 125 16-bit mastering (use with dither)", " -v very high 95% 175 24-bit mastering", " OVERRIDE OPTIONS (only with -m, -h, -v)", " -M/-I/-L Phase response = minimum/intermediate/linear(default)", " -s Steep filter (band-width = 99%)", " -a Allow aliasing above the pass-band", " -b 74-99.7 Any band-width %", " -p 0-100 Any phase response (0 = minimum, 25 = intermediate,", " 50 = linear, 100 = maximum)", }; static char * usage; handler.usage = lsx_usage_lines(&usage, lines, array_length(lines)); return &handler; } /*------------------- emulation of the old `rabbit' effect -------------------*/ static int rabbit_getopts(sox_effect_t * effp, int argc, char * * argv) { static char const * const qualities[] = {"-v", "-h", "-l", "-q", "-q"}; char quality[2] = "0", dummy; /* To check for extraneous chars. */ char * args[] = {0, 0, 0}; int argc2 = 2; if (argc > 1) { int n = sscanf(argv[1], "-c%1[0-4] %c", quality, &dummy); if (n > 1) return lsx_usage(effp); if (n == 1) --argc, ++argv; } args[0] = argv[0]; args[1] = (char *)qualities[quality[0] - '0']; if (argc > 1) { args[2] = argv[1]; --argc, ++argv; ++argc2; } return argc > 1? lsx_usage(effp) : lsx_rate_effect_fn()->getopts(effp, argc2, args); } sox_effect_handler_t const * lsx_rabbit_effect_fn(void) { static sox_effect_handler_t handler; handler = *lsx_rate_effect_fn(); handler.name = "rabbit"; handler.usage = "[-c0|-c1|-c2|-c3|-c4] [rate]"; handler.getopts = rabbit_getopts; handler.flags |= SOX_EFF_DEPRECATED; return &handler; } /*------------------ emulation of the old `polyphase' effect -----------------*/ static int polyphase_getopts(sox_effect_t * effp, int argc, char * * argv) { char arg[100], * args[] = {0, "-vb", 0}; double bandwidth = 95; for (--argc, ++argv; argc >= 2; argc -= 2, argv += 2) if (!strcmp(argv[0], "-cutoff")) bandwidth = 100 * atof(argv[1]); else if (strcmp(argv[0], "-w") && strcmp(argv[0], "-width")) { lsx_fail("unknown parameter: %s %s", argv[0], argv[1]); return SOX_EOF; } args[0] = argv[0]; args[2] = arg; sprintf(arg, "%f", bandwidth); return argc? lsx_usage(effp) : lsx_rate_effect_fn()->getopts(effp, (int)array_length(args), args); } sox_effect_handler_t const * lsx_polyphase_effect_fn(void) { static sox_effect_handler_t handler; handler = *lsx_rate_effect_fn(); handler.name = "polyphase"; handler.usage = "-cutoff factor Cutoff frequency 0 to 1, default 0.95"; handler.getopts = polyphase_getopts; handler.flags |= SOX_EFF_DEPRECATED; return &handler; } /*------------------ emulation of the old `resample' effect ------------------*/ static int resample_getopts(sox_effect_t * effp, int argc, char * * argv) { char arg[100], * args[] = {0, 0, "-b", 0}; double bandwidth = .8; char const * quality = NULL; --argc, ++argv; if (argc) { if (!strcmp(argv[0], "-qs")) { quality = "-h"; --argc, ++argv; } else if (!strcmp(argv[0], "-q")) { bandwidth = .875; quality = "-v"; --argc, ++argv; } else if (!strcmp(argv[0], "-ql")) { bandwidth = .94; quality = "-v"; --argc, ++argv; } } if (argc) { if (sscanf(argv[0], "%lf", &bandwidth) != 1) return lsx_usage(effp); if (!quality) quality = "-m"; } args[0] = argv[0]; args[1] = (char *)(quality? quality : "-l"); args[3] = arg; sprintf(arg, "%f", 100 * bandwidth); return argc > 2 ? lsx_usage(effp) : lsx_rate_effect_fn()->getopts(effp, quality? 4 : 2, args); } sox_effect_handler_t const * lsx_resample_effect_fn(void) { static sox_effect_handler_t handler; handler = *lsx_rate_effect_fn(); handler.name = "resample"; handler.usage = "[ -qs | -q | -ql ] [ rolloff [ beta ] ]", handler.getopts = resample_getopts; handler.flags |= SOX_EFF_DEPRECATED; return &handler; }