3 * Copyright (c) 2004 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
23 * @file libavcodec/resample2.c
25 * @author Michael Niedermayer <michaelni@gmx.at>
32 #ifndef CONFIG_RESAMPLE_HP
33 #define FILTER_SHIFT 15
36 #define FELEM2 int32_t
37 #define FELEML int64_t
38 #define FELEM_MAX INT16_MAX
39 #define FELEM_MIN INT16_MIN
41 #elif !defined(CONFIG_RESAMPLE_AUDIOPHILE_KIDDY_MODE)
42 #define FILTER_SHIFT 30
45 #define FELEM2 int64_t
46 #define FELEML int64_t
47 #define FELEM_MAX INT32_MAX
48 #define FELEM_MIN INT32_MIN
49 #define WINDOW_TYPE 12
51 #define FILTER_SHIFT 0
56 #define WINDOW_TYPE 24
59 #define PRE_FILTER_TABLE_PATH "/etc/pulse/filter"
61 typedef struct AVResampleContext{
69 int compensation_distance;
76 * 0th order modified bessel function of the first kind.
78 static double bessel(double x){
92 * builds a polyphase filterbank.
93 * @param factor resampling factor
94 * @param scale wanted sum of coefficients for each filter
95 * @param type 0->cubic, 1->blackman nuttall windowed sinc, 2..16->kaiser windowed sinc beta=2..16
97 void av_build_filter(FELEM *filter, double factor, int tap_count, int phase_count, int scale, int type){
99 double x, y, w, tab[tap_count];
100 const int center= (tap_count-1)/2;
102 /* if upsampling, only need to interpolate, no filter */
106 for(ph=0;ph<phase_count;ph++) {
108 for(i=0;i<tap_count;i++) {
109 x = M_PI * ((double)(i - center) - (double)ph / phase_count) * factor;
114 const float d= -0.5; //first order derivative = -0.5
115 x = fabs(((double)(i - center) - (double)ph / phase_count) * factor);
116 if(x<1.0) y= 1 - 3*x*x + 2*x*x*x + d*( -x*x + x*x*x);
117 else y= d*(-4 + 8*x - 5*x*x + x*x*x);
120 w = 2.0*x / (factor*tap_count) + M_PI;
121 y *= 0.3635819 - 0.4891775 * cos(w) + 0.1365995 * cos(2*w) - 0.0106411 * cos(3*w);
124 w = 2.0*x / (factor*tap_count*M_PI);
125 y *= bessel(type*sqrt(FFMAX(1-w*w, 0)));
133 /* normalize so that an uniform color remains the same */
134 for(i=0;i<tap_count;i++) {
135 #ifdef CONFIG_RESAMPLE_AUDIOPHILE_KIDDY_MODE
136 filter[ph * tap_count + i] = tab[i] / norm;
138 filter[ph * tap_count + i] = av_clip(lrintf(tab[i] * scale / norm), FELEM_MIN, FELEM_MAX);
146 double sine[LEN + tap_count];
147 double filtered[LEN];
148 double maxff=-2, minff=2, maxsf=-2, minsf=2;
149 for(i=0; i<LEN; i++){
150 double ss=0, sf=0, ff=0;
151 for(j=0; j<LEN+tap_count; j++)
152 sine[j]= cos(i*j*M_PI/LEN);
153 for(j=0; j<LEN; j++){
156 for(k=0; k<tap_count; k++)
157 sum += filter[ph * tap_count + k] * sine[k+j];
158 filtered[j]= sum / (1<<FILTER_SHIFT);
159 ss+= sine[j + center] * sine[j + center];
160 ff+= filtered[j] * filtered[j];
161 sf+= sine[j + center] * filtered[j];
166 maxff= FFMAX(maxff, ff);
167 minff= FFMIN(minff, ff);
168 maxsf= FFMAX(maxsf, sf);
169 minsf= FFMIN(minsf, sf);
171 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);
180 int64_t __gettime(void)
183 gettimeofday(&tv,NULL);
184 return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
187 #define PRELOAD_FILTER
189 AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_size, int phase_shift, int linear, double cutoff)
192 int64_t start = __gettime ();
193 printf("[%s][%d] out=%d, in=%d, filter_size=%d, phase_shift=%d, linear=%d, cutoff=%f\n", __func__, __LINE__,
194 out_rate, in_rate, filter_size, phase_shift, linear, cutoff);
196 AVResampleContext *c= av_mallocz(sizeof(AVResampleContext));
197 double factor= FFMIN(out_rate * cutoff / in_rate, 1.0);
198 int phase_count= 1<<phase_shift;
200 c->phase_shift= phase_shift;
201 c->phase_mask= phase_count-1;
204 c->filter_length= FFMAX((int)ceil(filter_size/factor), 1);
205 c->filter_bank= av_mallocz(c->filter_length*(phase_count+1)*sizeof(FELEM));
207 printf("factor=%f, filter length=%d, filter_bank size=%d\n", factor, c->filter_length, c->filter_length*(phase_count+1)*sizeof(FELEM));
210 int filter_bank_size = c->filter_length*(phase_count+1)*sizeof(FELEM);
212 #ifndef PRELOAD_FILTER
213 av_build_filter(c->filter_bank, factor, c->filter_length, phase_count, 1<<FILTER_SHIFT, WINDOW_TYPE);
214 #else // PRELOAD_FILTER
215 char filter_data_name[256];
216 pa_snprintf (filter_data_name, sizeof(filter_data_name), "%s/filter_%d_%d.dat", PRE_FILTER_TABLE_PATH, in_rate, out_rate);
219 printf ("filter_data_name = %s\n", filter_data_name);
222 /* Check whether pre-created file is exists */
223 FILE* f1 = fopen(filter_data_name, "r");
225 /* Read pre-created filter data */
226 if (fread (c->filter_bank, 1, filter_bank_size, f1) != filter_bank_size) {
227 printf ("Error!!! Loading Filter [%s]!!!!!\n", filter_data_name);
229 printf ("Filter [%s] Loaded!!!!\n", filter_data_name);
233 /* If not exist, Create filter data */
234 av_build_filter(c->filter_bank, factor, c->filter_length, phase_count, 1<<FILTER_SHIFT, WINDOW_TYPE);
236 /* Save filter data */
237 FILE* f2 = fopen(filter_data_name, "w");
239 if (fwrite(c->filter_bank, 1, filter_bank_size, f2) == filter_bank_size) {
240 printf ("Filter data [%s] saved\n", filter_data_name);
242 printf ("Error!!! Writing Filter data [%s]\n", filter_data_name);
246 printf ("Error!!! Failed to open filter data file [%s]\n", filter_data_name);
250 #endif // PRELOAD_FILTER
251 memcpy(&c->filter_bank[c->filter_length*phase_count+1], c->filter_bank, (c->filter_length-1)*sizeof(FELEM));
252 c->filter_bank[c->filter_length*phase_count]= c->filter_bank[c->filter_length - 1];
254 c->src_incr= out_rate;
255 c->ideal_dst_incr= c->dst_incr= in_rate * phase_count;
256 c->index= -phase_count*((c->filter_length-1)/2);
258 printf("[%s][%d] elapsed = %lld\n", __func__, __LINE__, __gettime() - start);
264 void av_resample_close(AVResampleContext *c){
265 av_freep(&c->filter_bank);
269 void av_resample_compensate(AVResampleContext *c, int sample_delta, int compensation_distance){
270 // sample_delta += (c->ideal_dst_incr - c->dst_incr)*(int64_t)c->compensation_distance / c->ideal_dst_incr;
271 c->compensation_distance= compensation_distance;
272 c->dst_incr = c->ideal_dst_incr - c->ideal_dst_incr * (int64_t)sample_delta / compensation_distance;
275 int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx){
279 int dst_incr_frac= c->dst_incr % c->src_incr;
280 int dst_incr= c->dst_incr / c->src_incr;
281 int compensation_distance= c->compensation_distance;
283 if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
284 int64_t index2= ((int64_t)index)<<32;
285 int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
286 dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
288 for(dst_index=0; dst_index < dst_size; dst_index++){
289 dst[dst_index] = src[index2>>32];
292 frac += dst_index * dst_incr_frac;
293 index += dst_index * dst_incr;
294 index += frac / c->src_incr;
297 for(dst_index=0; dst_index < dst_size; dst_index++){
298 FELEM *filter= c->filter_bank + c->filter_length*(index & c->phase_mask);
299 int sample_index= index >> c->phase_shift;
302 if(sample_index < 0){
303 for(i=0; i<c->filter_length; i++)
304 val += src[FFABS(sample_index + i) % src_size] * filter[i];
305 }else if(sample_index + c->filter_length > src_size){
309 for(i=0; i<c->filter_length; i++){
310 val += src[sample_index + i] * (FELEM2)filter[i];
311 v2 += src[sample_index + i] * (FELEM2)filter[i + c->filter_length];
313 val+=(v2-val)*(FELEML)frac / c->src_incr;
315 for(i=0; i<c->filter_length; i++){
316 val += src[sample_index + i] * (FELEM2)filter[i];
320 #ifdef CONFIG_RESAMPLE_AUDIOPHILE_KIDDY_MODE
321 dst[dst_index] = av_clip_int16(lrintf(val));
323 val = (val + (1<<(FILTER_SHIFT-1)))>>FILTER_SHIFT;
324 dst[dst_index] = (unsigned)(val + 32768) > 65535 ? (val>>31) ^ 32767 : val;
327 frac += dst_incr_frac;
329 if(frac >= c->src_incr){
334 if(dst_index + 1 == compensation_distance){
335 compensation_distance= 0;
336 dst_incr_frac= c->ideal_dst_incr % c->src_incr;
337 dst_incr= c->ideal_dst_incr / c->src_incr;
341 *consumed= FFMAX(index, 0) >> c->phase_shift;
342 if(index>=0) index &= c->phase_mask;
344 if(compensation_distance){
345 compensation_distance -= dst_index;
346 assert(compensation_distance > 0);
351 c->dst_incr= dst_incr_frac + c->src_incr*dst_incr;
352 c->compensation_distance= compensation_distance;
355 if(update_ctx && !c->compensation_distance){
357 av_resample_compensate(c, rand() % (8000*2) - 8000, 8000*2);
358 av_log(NULL, AV_LOG_DEBUG, "%d %d %d\n", c->dst_incr, c->ideal_dst_incr, c->compensation_distance);