3 * Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #include "libavutil/log.h"
29 #include "libavutil/avassert.h"
30 #include "swresample_internal.h"
36 typedef struct ResampleContext {
37 const AVClass *av_class;
45 int compensation_distance;
50 enum AVSampleFormat format;
56 * 0th order modified bessel function of the first kind.
58 static double bessel(double x){
63 static const double inv[100]={
64 1.0/( 1* 1), 1.0/( 2* 2), 1.0/( 3* 3), 1.0/( 4* 4), 1.0/( 5* 5), 1.0/( 6* 6), 1.0/( 7* 7), 1.0/( 8* 8), 1.0/( 9* 9), 1.0/(10*10),
65 1.0/(11*11), 1.0/(12*12), 1.0/(13*13), 1.0/(14*14), 1.0/(15*15), 1.0/(16*16), 1.0/(17*17), 1.0/(18*18), 1.0/(19*19), 1.0/(20*20),
66 1.0/(21*21), 1.0/(22*22), 1.0/(23*23), 1.0/(24*24), 1.0/(25*25), 1.0/(26*26), 1.0/(27*27), 1.0/(28*28), 1.0/(29*29), 1.0/(30*30),
67 1.0/(31*31), 1.0/(32*32), 1.0/(33*33), 1.0/(34*34), 1.0/(35*35), 1.0/(36*36), 1.0/(37*37), 1.0/(38*38), 1.0/(39*39), 1.0/(40*40),
68 1.0/(41*41), 1.0/(42*42), 1.0/(43*43), 1.0/(44*44), 1.0/(45*45), 1.0/(46*46), 1.0/(47*47), 1.0/(48*48), 1.0/(49*49), 1.0/(50*50),
69 1.0/(51*51), 1.0/(52*52), 1.0/(53*53), 1.0/(54*54), 1.0/(55*55), 1.0/(56*56), 1.0/(57*57), 1.0/(58*58), 1.0/(59*59), 1.0/(60*60),
70 1.0/(61*61), 1.0/(62*62), 1.0/(63*63), 1.0/(64*64), 1.0/(65*65), 1.0/(66*66), 1.0/(67*67), 1.0/(68*68), 1.0/(69*69), 1.0/(70*70),
71 1.0/(71*71), 1.0/(72*72), 1.0/(73*73), 1.0/(74*74), 1.0/(75*75), 1.0/(76*76), 1.0/(77*77), 1.0/(78*78), 1.0/(79*79), 1.0/(80*80),
72 1.0/(81*81), 1.0/(82*82), 1.0/(83*83), 1.0/(84*84), 1.0/(85*85), 1.0/(86*86), 1.0/(87*87), 1.0/(88*88), 1.0/(89*89), 1.0/(90*90),
73 1.0/(91*91), 1.0/(92*92), 1.0/(93*93), 1.0/(94*94), 1.0/(95*95), 1.0/(96*96), 1.0/(97*97), 1.0/(98*98), 1.0/(99*99), 1.0/(10000)
77 for(i=0; v != lastv; i++){
86 * builds a polyphase filterbank.
87 * @param factor resampling factor
88 * @param scale wanted sum of coefficients for each filter
89 * @param type 0->cubic, 1->blackman nuttall windowed sinc, 2..16->kaiser windowed sinc beta=2..16
90 * @return 0 on success, negative on error
92 static int build_filter(ResampleContext *c, void *filter, double factor, int tap_count, int phase_count, int scale, int type){
95 double *tab = av_malloc(tap_count * sizeof(*tab));
96 const int center= (tap_count-1)/2;
99 return AVERROR(ENOMEM);
101 /* if upsampling, only need to interpolate, no filter */
105 for(ph=0;ph<phase_count;ph++) {
107 for(i=0;i<tap_count;i++) {
108 x = M_PI * ((double)(i - center) - (double)ph / phase_count) * factor;
113 const float d= -0.5; //first order derivative = -0.5
114 x = fabs(((double)(i - center) - (double)ph / phase_count) * factor);
115 if(x<1.0) y= 1 - 3*x*x + 2*x*x*x + d*( -x*x + x*x*x);
116 else y= d*(-4 + 8*x - 5*x*x + x*x*x);
119 w = 2.0*x / (factor*tap_count) + M_PI;
120 y *= 0.3635819 - 0.4891775 * cos(w) + 0.1365995 * cos(2*w) - 0.0106411 * cos(3*w);
123 w = 2.0*x / (factor*tap_count*M_PI);
124 y *= bessel(type*sqrt(FFMAX(1-w*w, 0)));
132 /* normalize so that an uniform color remains the same */
134 case AV_SAMPLE_FMT_S16:
135 for(i=0;i<tap_count;i++)
136 ((int16_t*)filter)[ph * tap_count + i] = av_clip(lrintf(tab[i] * scale / norm), INT16_MIN, INT16_MAX);
138 case AV_SAMPLE_FMT_S32:
139 for(i=0;i<tap_count;i++)
140 ((int32_t*)filter)[ph * tap_count + i] = av_clip(lrintf(tab[i] * scale / norm), INT32_MIN, INT32_MAX);
142 case AV_SAMPLE_FMT_FLT:
143 for(i=0;i<tap_count;i++)
144 ((float*)filter)[ph * tap_count + i] = tab[i] * scale / norm;
146 case AV_SAMPLE_FMT_DBL:
147 for(i=0;i<tap_count;i++)
148 ((double*)filter)[ph * tap_count + i] = tab[i] * scale / norm;
156 double sine[LEN + tap_count];
157 double filtered[LEN];
158 double maxff=-2, minff=2, maxsf=-2, minsf=2;
159 for(i=0; i<LEN; i++){
160 double ss=0, sf=0, ff=0;
161 for(j=0; j<LEN+tap_count; j++)
162 sine[j]= cos(i*j*M_PI/LEN);
163 for(j=0; j<LEN; j++){
166 for(k=0; k<tap_count; k++)
167 sum += filter[ph * tap_count + k] * sine[k+j];
168 filtered[j]= sum / (1<<FILTER_SHIFT);
169 ss+= sine[j + center] * sine[j + center];
170 ff+= filtered[j] * filtered[j];
171 sf+= sine[j + center] * filtered[j];
176 maxff= FFMAX(maxff, ff);
177 minff= FFMIN(minff, ff);
178 maxsf= FFMAX(maxsf, sf);
179 minsf= FFMIN(minsf, sf);
181 av_log(NULL, AV_LOG_ERROR, "i:%4d ss:%f ff:%13.6e-%13.6e sf:%13.6e-%13.6e\n", i, ss, maxff, minff, maxsf, minsf);
193 ResampleContext *swri_resample_init(ResampleContext *c, int out_rate, int in_rate, int filter_size, int phase_shift, int linear, double cutoff, enum AVSampleFormat format){
194 double factor= FFMIN(out_rate * cutoff / in_rate, 1.0);
195 int phase_count= 1<<phase_shift;
197 if (!c || c->phase_shift != phase_shift || c->linear!=linear || c->factor != factor
198 || c->filter_length != FFMAX((int)ceil(filter_size/factor), 1) || c->format != format) {
199 c = av_mallocz(sizeof(*c));
205 c->felem_size= av_get_bytes_per_sample(c->format);
208 case AV_SAMPLE_FMT_S16:
209 c->filter_shift = 15;
211 case AV_SAMPLE_FMT_S32:
212 c->filter_shift = 30;
214 case AV_SAMPLE_FMT_FLT:
215 case AV_SAMPLE_FMT_DBL:
219 av_log(NULL, AV_LOG_ERROR, "Unsupported sample format\n");
223 c->phase_shift = phase_shift;
224 c->phase_mask = phase_count - 1;
227 c->filter_length = FFMAX((int)ceil(filter_size/factor), 1);
228 c->filter_bank = av_mallocz(c->filter_length*(phase_count+1)*c->felem_size);
231 if (build_filter(c, (void*)c->filter_bank, factor, c->filter_length, phase_count, 1<<c->filter_shift, WINDOW_TYPE))
233 memcpy(c->filter_bank + (c->filter_length*phase_count+1)*c->felem_size, c->filter_bank, (c->filter_length-1)*c->felem_size);
234 memcpy(c->filter_bank + (c->filter_length*phase_count )*c->felem_size, c->filter_bank + (c->filter_length - 1)*c->felem_size, c->felem_size);
237 c->compensation_distance= 0;
238 if(!av_reduce(&c->src_incr, &c->dst_incr, out_rate, in_rate * (int64_t)phase_count, INT32_MAX/2))
240 c->ideal_dst_incr= c->dst_incr;
242 c->index= -phase_count*((c->filter_length-1)/2);
247 av_free(c->filter_bank);
252 void swri_resample_free(ResampleContext **c){
255 av_freep(&(*c)->filter_bank);
259 int swr_set_compensation(struct SwrContext *s, int sample_delta, int compensation_distance){
263 if (!s || compensation_distance < 0)
264 return AVERROR(EINVAL);
265 if (!compensation_distance && sample_delta)
266 return AVERROR(EINVAL);
268 s->flags |= SWR_FLAG_RESAMPLE;
274 c->compensation_distance= compensation_distance;
275 if (compensation_distance)
276 c->dst_incr = c->ideal_dst_incr - c->ideal_dst_incr * (int64_t)sample_delta / compensation_distance;
278 c->dst_incr = c->ideal_dst_incr;
282 #define RENAME(N) N ## _int16
283 #define FILTER_SHIFT 15
284 #define DELEM int16_t
285 #define FELEM int16_t
286 #define FELEM2 int32_t
287 #define FELEML int64_t
288 #define FELEM_MAX INT16_MAX
289 #define FELEM_MIN INT16_MIN
290 #define OUT(d, v) v = (v + (1<<(FILTER_SHIFT-1)))>>FILTER_SHIFT;\
291 d = (unsigned)(v + 32768) > 65535 ? (v>>31) ^ 32767 : v
292 #include "resample_template.c"
305 #define RENAME(N) N ## _int32
306 #define FILTER_SHIFT 30
307 #define DELEM int32_t
308 #define FELEM int32_t
309 #define FELEM2 int64_t
310 #define FELEML int64_t
311 #define FELEM_MAX INT32_MAX
312 #define FELEM_MIN INT32_MIN
313 #define OUT(d, v) v = (v + (1<<(FILTER_SHIFT-1)))>>FILTER_SHIFT;\
314 d = (uint64_t)(v + 0x80000000) > 0xFFFFFFFF ? (v>>63) ^ 0x7FFFFFFF : v
315 #include "resample_template.c"
328 #define RENAME(N) N ## _float
329 #define FILTER_SHIFT 0
334 #define OUT(d, v) d = v
335 #include "resample_template.c"
348 #define RENAME(N) N ## _double
349 #define FILTER_SHIFT 0
352 #define FELEM2 double
353 #define FELEML double
354 #define OUT(d, v) d = v
355 #include "resample_template.c"
358 int swri_multiple_resample(ResampleContext *c, AudioData *dst, int dst_size, AudioData *src, int src_size, int *consumed){
361 for(i=0; i<dst->ch_count; i++){
362 if(c->format == AV_SAMPLE_FMT_S16) ret= swri_resample_int16(c, (int16_t*)dst->ch[i], (const int16_t*)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);
363 if(c->format == AV_SAMPLE_FMT_S32) ret= swri_resample_int32(c, (int32_t*)dst->ch[i], (const int32_t*)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);
364 if(c->format == AV_SAMPLE_FMT_FLT) ret= swri_resample_float(c, (float *)dst->ch[i], (const float *)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);
365 if(c->format == AV_SAMPLE_FMT_DBL) ret= swri_resample_double(c,(double *)dst->ch[i], (const double *)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);