FFmpeg: libswresample/resample.c Source File

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libswresample

resample.c

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1 /*

2 * audio resampling

4 *

5 * This file is part of FFmpeg.

6 *

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.

11 *

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.

16 *

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

20 */

22 /**

23 * @file

24 * audio resampling

25 * @author Michael Niedermayer <michaelni@gmx.at>

26 */

28 #include "libavutil/log.h"

29 #include "libavutil/avassert.h"

30 #include "swresample_internal.h"

33 typedef struct ResampleContext {

34 const AVClass *av_class;

35 uint8_t *filter_bank;

36 int filter_length;

37 int filter_alloc;

38 int ideal_dst_incr;

39 int dst_incr;

40 int index;

41 int frac;

42 int src_incr;

43 int compensation_distance;

44 int phase_shift;

45 int phase_mask;

46 int linear;

47 enum SwrFilterType filter_type;

48 int kaiser_beta;

49 double factor;

50 enum AVSampleFormat format;

51 int felem_size;

52 int filter_shift;

53 } ResampleContext;

55 /**

56 * 0th order modified bessel function of the first kind.

57 */

58 static double bessel(double x){

59 double v=1;

60 double lastv=0;

61 double t=1;

62 int i;

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)

74 };

76 x= x*x/4;

77 for(i=0; v != lastv; i++){

78 lastv=v;

79 t *= x*inv[i];

80 v += t;

81 av_assert2(i<99);

82 }

83 return v;

84 }

86 /**

87 * builds a polyphase filterbank.

88 * @param factor resampling factor

89 * @param scale wanted sum of coefficients for each filter

90 * @param filter_type filter type

91 * @param kaiser_beta kaiser window beta

92 * @return 0 on success, negative on error

93 */

94 static int build_filter(ResampleContext *c, void *filter, double factor, int tap_count, int alloc, int phase_count, int scale,

95 int filter_type, int kaiser_beta){

96 int ph, i;

97 double x, y, w;

98 double *tab = av_malloc(tap_count * sizeof(*tab));

99 const int center= (tap_count-1)/2;

100

101 if (!tab)

102 return AVERROR(ENOMEM);

103

104 /* if upsampling, only need to interpolate, no filter */

105 if (factor > 1.0)

106 factor = 1.0;

107

108 for(ph=0;ph<phase_count;ph++) {

109 double norm = 0;

110 for(i=0;i<tap_count;i++) {

111 x = M_PI * ((double)(i - center) - (double)ph / phase_count) * factor;

112 if (x == 0) y = 1.0;

113 else y = sin(x) / x;

114 switch(filter_type){

115 case SWR_FILTER_TYPE_CUBIC:{

116 const float d= -0.5; //first order derivative = -0.5

117 x = fabs(((double)(i - center) - (double)ph / phase_count) * factor);

118 if(x<1.0) y= 1 - 3*x*x + 2*x*x*x + d*( -x*x + x*x*x);

119 else y= d*(-4 + 8*x - 5*x*x + x*x*x);

120 break;}

121 case SWR_FILTER_TYPE_BLACKMAN_NUTTALL:

122 w = 2.0*x / (factor*tap_count) + M_PI;

123 y *= 0.3635819 - 0.4891775 * cos(w) + 0.1365995 * cos(2*w) - 0.0106411 * cos(3*w);

124 break;

125 case SWR_FILTER_TYPE_KAISER:

126 w = 2.0*x / (factor*tap_count*M_PI);

127 y *= bessel(kaiser_beta*sqrt(FFMAX(1-w*w, 0)));

128 break;

129 default:

130 av_assert0(0);

131 }

132

133 tab[i] = y;

134 norm += y;

135 }

136

137 /* normalize so that an uniform color remains the same */

138 switch(c->format){

139 case AV_SAMPLE_FMT_S16P:

140 for(i=0;i<tap_count;i++)

141 ((int16_t*)filter)[ph * alloc + i] = av_clip(lrintf(tab[i] * scale / norm), INT16_MIN, INT16_MAX);

142 break;

143 case AV_SAMPLE_FMT_S32P:

144 for(i=0;i<tap_count;i++)

145 ((int32_t*)filter)[ph * alloc + i] = av_clipl_int32(llrint(tab[i] * scale / norm));

146 break;

147 case AV_SAMPLE_FMT_FLTP:

148 for(i=0;i<tap_count;i++)

149 ((float*)filter)[ph * alloc + i] = tab[i] * scale / norm;

150 break;

151 case AV_SAMPLE_FMT_DBLP:

152 for(i=0;i<tap_count;i++)

153 ((double*)filter)[ph * alloc + i] = tab[i] * scale / norm;

154 break;

155 }

156 }

157 #if 0

158 {

159 #define LEN 1024

160 int j,k;

161 double sine[LEN + tap_count];

162 double filtered[LEN];

163 double maxff=-2, minff=2, maxsf=-2, minsf=2;

164 for(i=0; i<LEN; i++){

165 double ss=0, sf=0, ff=0;

166 for(j=0; j<LEN+tap_count; j++)

167 sine[j]= cos(i*j*M_PI/LEN);

168 for(j=0; j<LEN; j++){

169 double sum=0;

170 ph=0;

171 for(k=0; k<tap_count; k++)

172 sum += filter[ph * tap_count + k] * sine[k+j];

173 filtered[j]= sum / (1<<FILTER_SHIFT);

174 ss+= sine[j + center] * sine[j + center];

175 ff+= filtered[j] * filtered[j];

176 sf+= sine[j + center] * filtered[j];

177 }

178 ss= sqrt(2*ss/LEN);

179 ff= sqrt(2*ff/LEN);

180 sf= 2*sf/LEN;

181 maxff= FFMAX(maxff, ff);

182 minff= FFMIN(minff, ff);

183 maxsf= FFMAX(maxsf, sf);

184 minsf= FFMIN(minsf, sf);

185 if(i%11==0){

186 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);

187 minff=minsf= 2;

188 maxff=maxsf= -2;

189 }

190 }

191 }

192 #endif

193

194 av_free(tab);

195 return 0;

196 }

197

198 static ResampleContext *resample_init(ResampleContext *c, int out_rate, int in_rate, int filter_size, int phase_shift, int linear,

199 double cutoff0, enum AVSampleFormat format, enum SwrFilterType filter_type, int kaiser_beta,

200 double precision, int cheby){

201 double cutoff = cutoff0? cutoff0 : 0.97;

202 double factor= FFMIN(out_rate * cutoff / in_rate, 1.0);

203 int phase_count= 1<<phase_shift;

204

205 if (!c || c->phase_shift != phase_shift || c->linear!=linear || c->factor != factor

206 || c->filter_length != FFMAX((int)ceil(filter_size/factor), 1) || c->format != format

207 || c->filter_type != filter_type || c->kaiser_beta != kaiser_beta) {

208 c = av_mallocz(sizeof(*c));

209 if (!c)

210 return NULL;

211

212 c->format= format;

213

214 c->felem_size= av_get_bytes_per_sample(c->format);

215

216 switch(c->format){

217 case AV_SAMPLE_FMT_S16P:

218 c->filter_shift = 15;

219 break;

220 case AV_SAMPLE_FMT_S32P:

221 c->filter_shift = 30;

222 break;

223 case AV_SAMPLE_FMT_FLTP:

224 case AV_SAMPLE_FMT_DBLP:

225 c->filter_shift = 0;

226 break;

227 default:

228 av_log(NULL, AV_LOG_ERROR, "Unsupported sample format\n");

229 av_assert0(0);

230 }

231

232 c->phase_shift = phase_shift;

233 c->phase_mask = phase_count - 1;

234 c->linear = linear;

235 c->factor = factor;

236 c->filter_length = FFMAX((int)ceil(filter_size/factor), 1);

237 c->filter_alloc = FFALIGN(c->filter_length, 8);

238 c->filter_bank = av_calloc(c->filter_alloc, (phase_count+1)*c->felem_size);

239 c->filter_type = filter_type;

240 c->kaiser_beta = kaiser_beta;

241 if (!c->filter_bank)

242 goto error;

243 if (build_filter(c, (void*)c->filter_bank, factor, c->filter_length, c->filter_alloc, phase_count, 1<<c->filter_shift, filter_type, kaiser_beta))

244 goto error;

245 memcpy(c->filter_bank + (c->filter_alloc*phase_count+1)*c->felem_size, c->filter_bank, (c->filter_alloc-1)*c->felem_size);

246 memcpy(c->filter_bank + (c->filter_alloc*phase_count )*c->felem_size, c->filter_bank + (c->filter_alloc - 1)*c->felem_size, c->felem_size);

247 }

248

249 c->compensation_distance= 0;

250 if(!av_reduce(&c->src_incr, &c->dst_incr, out_rate, in_rate * (int64_t)phase_count, INT32_MAX/2))

251 goto error;

252 c->ideal_dst_incr= c->dst_incr;

253

254 c->index= -phase_count*((c->filter_length-1)/2);

255 c->frac= 0;

256

257 return c;

258 error:

259 av_freep(&c->filter_bank);

260 av_free(c);

261 return NULL;

262 }

263

264 static void resample_free(ResampleContext **c){

265 if(!*c)

266 return;

267 av_freep(&(*c)->filter_bank);

268 av_freep(c);

269 }

270

271 static int set_compensation(ResampleContext *c, int sample_delta, int compensation_distance){

272 c->compensation_distance= compensation_distance;

273 if (compensation_distance)

274 c->dst_incr = c->ideal_dst_incr - c->ideal_dst_incr * (int64_t)sample_delta / compensation_distance;

275 else

276 c->dst_incr = c->ideal_dst_incr;

277 return 0;

278 }

279

280 #define TEMPLATE_RESAMPLE_S16

281 #include "resample_template.c"

282 #undef TEMPLATE_RESAMPLE_S16

283

284 #define TEMPLATE_RESAMPLE_S32

285 #include "resample_template.c"

286 #undef TEMPLATE_RESAMPLE_S32

287

288 #define TEMPLATE_RESAMPLE_FLT

289 #include "resample_template.c"

290 #undef TEMPLATE_RESAMPLE_FLT

291

292 #define TEMPLATE_RESAMPLE_DBL

293 #include "resample_template.c"

294 #undef TEMPLATE_RESAMPLE_DBL

295

296 // XXX FIXME the whole C loop should be written in asm so this x86 specific code here isnt needed

297 #if HAVE_MMXEXT_INLINE

298

299 #include "x86/resample_mmx.h"

300

301 #define TEMPLATE_RESAMPLE_S16_MMX2

302 #include "resample_template.c"

303 #undef TEMPLATE_RESAMPLE_S16_MMX2

304

305 #if HAVE_SSSE3_INLINE

306 #define TEMPLATE_RESAMPLE_S16_SSSE3

307 #include "resample_template.c"

308 #undef TEMPLATE_RESAMPLE_S16_SSSE3

309 #endif

310

311 #endif // HAVE_MMXEXT_INLINE

312

313 static int multiple_resample(ResampleContext *c, AudioData *dst, int dst_size, AudioData *src, int src_size, int *consumed){

314 int i, ret= -1;

315 int av_unused mm_flags = av_get_cpu_flags();

316 int need_emms= 0;

317

318 for(i=0; i<dst->ch_count; i++){

319 #if HAVE_MMXEXT_INLINE

320 #if HAVE_SSSE3_INLINE

321 if(c->format == AV_SAMPLE_FMT_S16P && (mm_flags&AV_CPU_FLAG_SSSE3)) ret= swri_resample_int16_ssse3(c, (int16_t*)dst->ch[i], (const int16_t*)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);

322 else

323 #endif

324 if(c->format == AV_SAMPLE_FMT_S16P && (mm_flags&AV_CPU_FLAG_MMX2 )){

325 ret= swri_resample_int16_mmx2 (c, (int16_t*)dst->ch[i], (const int16_t*)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);

326 need_emms= 1;

327 } else

328 #endif

329 if(c->format == AV_SAMPLE_FMT_S16P) 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);

330 else if(c->format == AV_SAMPLE_FMT_S32P) 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);

331 else if(c->format == AV_SAMPLE_FMT_FLTP) ret= swri_resample_float(c, (float *)dst->ch[i], (const float *)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);

332 else if(c->format == AV_SAMPLE_FMT_DBLP) ret= swri_resample_double(c,(double *)dst->ch[i], (const double *)src->ch[i], consumed, src_size, dst_size, i+1==dst->ch_count);

333 }

334 if(need_emms)

335 emms_c();

336 return ret;

337 }

338

339 static int64_t get_delay(struct SwrContext *s, int64_t base){

340 ResampleContext *c = s->resample;

341 int64_t num = s->in_buffer_count - (c->filter_length-1)/2;

342 num <<= c->phase_shift;

343 num -= c->index;

344 num *= c->src_incr;