00001
00002
00003
00004
00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017
00018
00019
00020
00021
00022
00023
00029 #undef CONFIG_AC3ENC_FLOAT
00030 #include "ac3enc.c"
00031
00032
00034 #define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
00035
00036
00040 static av_cold void mdct_end(AC3MDCTContext *mdct)
00041 {
00042 mdct->nbits = 0;
00043 av_freep(&mdct->costab);
00044 av_freep(&mdct->sintab);
00045 av_freep(&mdct->xcos1);
00046 av_freep(&mdct->xsin1);
00047 av_freep(&mdct->rot_tmp);
00048 av_freep(&mdct->cplx_tmp);
00049 }
00050
00051
00056 static av_cold int fft_init(AVCodecContext *avctx, AC3MDCTContext *mdct, int ln)
00057 {
00058 int i, n, n2;
00059 float alpha;
00060
00061 n = 1 << ln;
00062 n2 = n >> 1;
00063
00064 FF_ALLOC_OR_GOTO(avctx, mdct->costab, n2 * sizeof(*mdct->costab), fft_alloc_fail);
00065 FF_ALLOC_OR_GOTO(avctx, mdct->sintab, n2 * sizeof(*mdct->sintab), fft_alloc_fail);
00066
00067 for (i = 0; i < n2; i++) {
00068 alpha = 2.0 * M_PI * i / n;
00069 mdct->costab[i] = FIX15(cos(alpha));
00070 mdct->sintab[i] = FIX15(sin(alpha));
00071 }
00072
00073 return 0;
00074 fft_alloc_fail:
00075 mdct_end(mdct);
00076 return AVERROR(ENOMEM);
00077 }
00078
00079
00084 static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
00085 int nbits)
00086 {
00087 int i, n, n4, ret;
00088
00089 n = 1 << nbits;
00090 n4 = n >> 2;
00091
00092 mdct->nbits = nbits;
00093
00094 ret = fft_init(avctx, mdct, nbits - 2);
00095 if (ret)
00096 return ret;
00097
00098 mdct->window = ff_ac3_window;
00099
00100 FF_ALLOC_OR_GOTO(avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1), mdct_alloc_fail);
00101 FF_ALLOC_OR_GOTO(avctx, mdct->xsin1, n4 * sizeof(*mdct->xsin1), mdct_alloc_fail);
00102 FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp), mdct_alloc_fail);
00103 FF_ALLOC_OR_GOTO(avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp), mdct_alloc_fail);
00104
00105 for (i = 0; i < n4; i++) {
00106 float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
00107 mdct->xcos1[i] = FIX15(-cos(alpha));
00108 mdct->xsin1[i] = FIX15(-sin(alpha));
00109 }
00110
00111 return 0;
00112 mdct_alloc_fail:
00113 mdct_end(mdct);
00114 return AVERROR(ENOMEM);
00115 }
00116
00117
00119 #define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
00120 { \
00121 int ax, ay, bx, by; \
00122 bx = pre1; \
00123 by = pim1; \
00124 ax = qre1; \
00125 ay = qim1; \
00126 pre = (bx + ax) >> 1; \
00127 pim = (by + ay) >> 1; \
00128 qre = (bx - ax) >> 1; \
00129 qim = (by - ay) >> 1; \
00130 }
00131
00132
00134 #define CMUL(pre, pim, are, aim, bre, bim) \
00135 { \
00136 pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15; \
00137 pim = (MUL16(are, bim) + MUL16(bre, aim)) >> 15; \
00138 }
00139
00140
00146 static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
00147 {
00148 int j, l, np, np2;
00149 int nblocks, nloops;
00150 register IComplex *p,*q;
00151 int tmp_re, tmp_im;
00152
00153 np = 1 << ln;
00154
00155
00156 for (j = 0; j < np; j++) {
00157 int k = av_reverse[j] >> (8 - ln);
00158 if (k < j)
00159 FFSWAP(IComplex, z[k], z[j]);
00160 }
00161
00162
00163
00164 p = &z[0];
00165 j = np >> 1;
00166 do {
00167 BF(p[0].re, p[0].im, p[1].re, p[1].im,
00168 p[0].re, p[0].im, p[1].re, p[1].im);
00169 p += 2;
00170 } while (--j);
00171
00172
00173
00174 p = &z[0];
00175 j = np >> 2;
00176 do {
00177 BF(p[0].re, p[0].im, p[2].re, p[2].im,
00178 p[0].re, p[0].im, p[2].re, p[2].im);
00179 BF(p[1].re, p[1].im, p[3].re, p[3].im,
00180 p[1].re, p[1].im, p[3].im, -p[3].re);
00181 p+=4;
00182 } while (--j);
00183
00184
00185
00186 nblocks = np >> 3;
00187 nloops = 1 << 2;
00188 np2 = np >> 1;
00189 do {
00190 p = z;
00191 q = z + nloops;
00192 for (j = 0; j < nblocks; j++) {
00193 BF(p->re, p->im, q->re, q->im,
00194 p->re, p->im, q->re, q->im);
00195 p++;
00196 q++;
00197 for(l = nblocks; l < np2; l += nblocks) {
00198 CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im);
00199 BF(p->re, p->im, q->re, q->im,
00200 p->re, p->im, tmp_re, tmp_im);
00201 p++;
00202 q++;
00203 }
00204 p += nloops;
00205 q += nloops;
00206 }
00207 nblocks = nblocks >> 1;
00208 nloops = nloops << 1;
00209 } while (nblocks);
00210 }
00211
00212
00218 static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
00219 {
00220 int i, re, im, n, n2, n4;
00221 int16_t *rot = mdct->rot_tmp;
00222 IComplex *x = mdct->cplx_tmp;
00223
00224 n = 1 << mdct->nbits;
00225 n2 = n >> 1;
00226 n4 = n >> 2;
00227
00228
00229 for (i = 0; i <n4; i++)
00230 rot[i] = -in[i + 3*n4];
00231 memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
00232
00233
00234 for (i = 0; i < n4; i++) {
00235 re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
00236 im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
00237 CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i]);
00238 }
00239
00240 fft(mdct, x, mdct->nbits - 2);
00241
00242
00243 for (i = 0; i < n4; i++) {
00244 re = x[i].re;
00245 im = x[i].im;
00246 CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i]);
00247 }
00248 }
00249
00250
00254 static void apply_window(DSPContext *dsp, int16_t *output, const int16_t *input,
00255 const int16_t *window, int n)
00256 {
00257 int i;
00258 int n2 = n >> 1;
00259
00260 for (i = 0; i < n2; i++) {
00261 output[i] = MUL16(input[i], window[i]) >> 15;
00262 output[n-i-1] = MUL16(input[n-i-1], window[i]) >> 15;
00263 }
00264 }
00265
00266
00273 static int log2_tab(AC3EncodeContext *s, int16_t *src, int len)
00274 {
00275 int v = s->ac3dsp.ac3_max_msb_abs_int16(src, len);
00276 return av_log2(v);
00277 }
00278
00279
00286 static void lshift_tab(int16_t *tab, int n, unsigned int lshift)
00287 {
00288 int i;
00289
00290 if (lshift > 0) {
00291 for (i = 0; i < n; i++)
00292 tab[i] <<= lshift;
00293 }
00294 }
00295
00296
00304 static int normalize_samples(AC3EncodeContext *s)
00305 {
00306 int v = 14 - log2_tab(s, s->windowed_samples, AC3_WINDOW_SIZE);
00307 lshift_tab(s->windowed_samples, AC3_WINDOW_SIZE, v);
00308 return v - 9;
00309 }
00310
00311
00315 static void scale_coefficients(AC3EncodeContext *s)
00316 {
00317
00318
00319 return;
00320 }
00321
00322
00323 #ifdef TEST
00324
00325
00326
00327 #include "libavutil/lfg.h"
00328
00329 #define MDCT_NBITS 9
00330 #define MDCT_SAMPLES (1 << MDCT_NBITS)
00331 #define FN (MDCT_SAMPLES/4)
00332
00333
00334 static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
00335 {
00336 IComplex in[FN], in1[FN];
00337 int k, n, i;
00338 float sum_re, sum_im, a;
00339
00340 for (i = 0; i < FN; i++) {
00341 in[i].re = av_lfg_get(lfg) % 65535 - 32767;
00342 in[i].im = av_lfg_get(lfg) % 65535 - 32767;
00343 in1[i] = in[i];
00344 }
00345 fft(mdct, in, 7);
00346
00347
00348 for (k = 0; k < FN; k++) {
00349 sum_re = 0;
00350 sum_im = 0;
00351 for (n = 0; n < FN; n++) {
00352 a = -2 * M_PI * (n * k) / FN;
00353 sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
00354 sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
00355 }
00356 av_log(NULL, AV_LOG_DEBUG, "%3d: %6d,%6d %6.0f,%6.0f\n",
00357 k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
00358 }
00359 }
00360
00361
00362 static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
00363 {
00364 int16_t input[MDCT_SAMPLES];
00365 int32_t output[AC3_MAX_COEFS];
00366 float input1[MDCT_SAMPLES];
00367 float output1[AC3_MAX_COEFS];
00368 float s, a, err, e, emax;
00369 int i, k, n;
00370
00371 for (i = 0; i < MDCT_SAMPLES; i++) {
00372 input[i] = (av_lfg_get(lfg) % 65535 - 32767) * 9 / 10;
00373 input1[i] = input[i];
00374 }
00375
00376 mdct512(mdct, output, input);
00377
00378
00379 for (k = 0; k < AC3_MAX_COEFS; k++) {
00380 s = 0;
00381 for (n = 0; n < MDCT_SAMPLES; n++) {
00382 a = (2*M_PI*(2*n+1+MDCT_SAMPLES/2)*(2*k+1) / (4 * MDCT_SAMPLES));
00383 s += input1[n] * cos(a);
00384 }
00385 output1[k] = -2 * s / MDCT_SAMPLES;
00386 }
00387
00388 err = 0;
00389 emax = 0;
00390 for (i = 0; i < AC3_MAX_COEFS; i++) {
00391 av_log(NULL, AV_LOG_DEBUG, "%3d: %7d %7.0f\n", i, output[i], output1[i]);
00392 e = output[i] - output1[i];
00393 if (e > emax)
00394 emax = e;
00395 err += e * e;
00396 }
00397 av_log(NULL, AV_LOG_DEBUG, "err2=%f emax=%f\n", err / AC3_MAX_COEFS, emax);
00398 }
00399
00400
00401 int main(void)
00402 {
00403 AVLFG lfg;
00404 AC3MDCTContext mdct;
00405
00406 mdct.avctx = NULL;
00407 av_log_set_level(AV_LOG_DEBUG);
00408 mdct_init(&mdct, 9);
00409
00410 fft_test(&mdct, &lfg);
00411 mdct_test(&mdct, &lfg);
00412
00413 return 0;
00414 }
00415 #endif
00416
00417
00418 AVCodec ff_ac3_fixed_encoder = {
00419 "ac3_fixed",
00420 AVMEDIA_TYPE_AUDIO,
00421 CODEC_ID_AC3,
00422 sizeof(AC3EncodeContext),
00423 ac3_encode_init,
00424 ac3_encode_frame,
00425 ac3_encode_close,
00426 NULL,
00427 .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00428 .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
00429 .channel_layouts = ac3_channel_layouts,
00430 };