dbf-halloween2015
diff libs/vorbis/mdct.c @ 1:c3f5c32cb210
barfed all the libraries in the source tree to make porting easier
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sun, 01 Nov 2015 00:36:56 +0200 |
| parents | |
| children |
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1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/libs/vorbis/mdct.c Sun Nov 01 00:36:56 2015 +0200 1.3 @@ -0,0 +1,563 @@ 1.4 +/******************************************************************** 1.5 + * * 1.6 + * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * 1.7 + * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * 1.8 + * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * 1.9 + * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * 1.10 + * * 1.11 + * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * 1.12 + * by the Xiph.Org Foundation http://www.xiph.org/ * 1.13 + * * 1.14 + ******************************************************************** 1.15 + 1.16 + function: normalized modified discrete cosine transform 1.17 + power of two length transform only [64 <= n ] 1.18 + last mod: $Id: mdct.c 16227 2009-07-08 06:58:46Z xiphmont $ 1.19 + 1.20 + Original algorithm adapted long ago from _The use of multirate filter 1.21 + banks for coding of high quality digital audio_, by T. Sporer, 1.22 + K. Brandenburg and B. Edler, collection of the European Signal 1.23 + Processing Conference (EUSIPCO), Amsterdam, June 1992, Vol.1, pp 1.24 + 211-214 1.25 + 1.26 + The below code implements an algorithm that no longer looks much like 1.27 + that presented in the paper, but the basic structure remains if you 1.28 + dig deep enough to see it. 1.29 + 1.30 + This module DOES NOT INCLUDE code to generate/apply the window 1.31 + function. Everybody has their own weird favorite including me... I 1.32 + happen to like the properties of y=sin(.5PI*sin^2(x)), but others may 1.33 + vehemently disagree. 1.34 + 1.35 + ********************************************************************/ 1.36 + 1.37 +/* this can also be run as an integer transform by uncommenting a 1.38 + define in mdct.h; the integerization is a first pass and although 1.39 + it's likely stable for Vorbis, the dynamic range is constrained and 1.40 + roundoff isn't done (so it's noisy). Consider it functional, but 1.41 + only a starting point. There's no point on a machine with an FPU */ 1.42 + 1.43 +#include <stdio.h> 1.44 +#include <stdlib.h> 1.45 +#include <string.h> 1.46 +#include <math.h> 1.47 +#include "vorbis/codec.h" 1.48 +#include "mdct.h" 1.49 +#include "os.h" 1.50 +#include "misc.h" 1.51 + 1.52 +/* build lookups for trig functions; also pre-figure scaling and 1.53 + some window function algebra. */ 1.54 + 1.55 +void mdct_init(mdct_lookup *lookup,int n){ 1.56 + int *bitrev=_ogg_malloc(sizeof(*bitrev)*(n/4)); 1.57 + DATA_TYPE *T=_ogg_malloc(sizeof(*T)*(n+n/4)); 1.58 + 1.59 + int i; 1.60 + int n2=n>>1; 1.61 + int log2n=lookup->log2n=rint(log((float)n)/log(2.f)); 1.62 + lookup->n=n; 1.63 + lookup->trig=T; 1.64 + lookup->bitrev=bitrev; 1.65 + 1.66 +/* trig lookups... */ 1.67 + 1.68 + for(i=0;i<n/4;i++){ 1.69 + T[i*2]=FLOAT_CONV(cos((M_PI/n)*(4*i))); 1.70 + T[i*2+1]=FLOAT_CONV(-sin((M_PI/n)*(4*i))); 1.71 + T[n2+i*2]=FLOAT_CONV(cos((M_PI/(2*n))*(2*i+1))); 1.72 + T[n2+i*2+1]=FLOAT_CONV(sin((M_PI/(2*n))*(2*i+1))); 1.73 + } 1.74 + for(i=0;i<n/8;i++){ 1.75 + T[n+i*2]=FLOAT_CONV(cos((M_PI/n)*(4*i+2))*.5); 1.76 + T[n+i*2+1]=FLOAT_CONV(-sin((M_PI/n)*(4*i+2))*.5); 1.77 + } 1.78 + 1.79 + /* bitreverse lookup... */ 1.80 + 1.81 + { 1.82 + int mask=(1<<(log2n-1))-1,i,j; 1.83 + int msb=1<<(log2n-2); 1.84 + for(i=0;i<n/8;i++){ 1.85 + int acc=0; 1.86 + for(j=0;msb>>j;j++) 1.87 + if((msb>>j)&i)acc|=1<<j; 1.88 + bitrev[i*2]=((~acc)&mask)-1; 1.89 + bitrev[i*2+1]=acc; 1.90 + 1.91 + } 1.92 + } 1.93 + lookup->scale=FLOAT_CONV(4.f/n); 1.94 +} 1.95 + 1.96 +/* 8 point butterfly (in place, 4 register) */ 1.97 +STIN void mdct_butterfly_8(DATA_TYPE *x){ 1.98 + REG_TYPE r0 = x[6] + x[2]; 1.99 + REG_TYPE r1 = x[6] - x[2]; 1.100 + REG_TYPE r2 = x[4] + x[0]; 1.101 + REG_TYPE r3 = x[4] - x[0]; 1.102 + 1.103 + x[6] = r0 + r2; 1.104 + x[4] = r0 - r2; 1.105 + 1.106 + r0 = x[5] - x[1]; 1.107 + r2 = x[7] - x[3]; 1.108 + x[0] = r1 + r0; 1.109 + x[2] = r1 - r0; 1.110 + 1.111 + r0 = x[5] + x[1]; 1.112 + r1 = x[7] + x[3]; 1.113 + x[3] = r2 + r3; 1.114 + x[1] = r2 - r3; 1.115 + x[7] = r1 + r0; 1.116 + x[5] = r1 - r0; 1.117 + 1.118 +} 1.119 + 1.120 +/* 16 point butterfly (in place, 4 register) */ 1.121 +STIN void mdct_butterfly_16(DATA_TYPE *x){ 1.122 + REG_TYPE r0 = x[1] - x[9]; 1.123 + REG_TYPE r1 = x[0] - x[8]; 1.124 + 1.125 + x[8] += x[0]; 1.126 + x[9] += x[1]; 1.127 + x[0] = MULT_NORM((r0 + r1) * cPI2_8); 1.128 + x[1] = MULT_NORM((r0 - r1) * cPI2_8); 1.129 + 1.130 + r0 = x[3] - x[11]; 1.131 + r1 = x[10] - x[2]; 1.132 + x[10] += x[2]; 1.133 + x[11] += x[3]; 1.134 + x[2] = r0; 1.135 + x[3] = r1; 1.136 + 1.137 + r0 = x[12] - x[4]; 1.138 + r1 = x[13] - x[5]; 1.139 + x[12] += x[4]; 1.140 + x[13] += x[5]; 1.141 + x[4] = MULT_NORM((r0 - r1) * cPI2_8); 1.142 + x[5] = MULT_NORM((r0 + r1) * cPI2_8); 1.143 + 1.144 + r0 = x[14] - x[6]; 1.145 + r1 = x[15] - x[7]; 1.146 + x[14] += x[6]; 1.147 + x[15] += x[7]; 1.148 + x[6] = r0; 1.149 + x[7] = r1; 1.150 + 1.151 + mdct_butterfly_8(x); 1.152 + mdct_butterfly_8(x+8); 1.153 +} 1.154 + 1.155 +/* 32 point butterfly (in place, 4 register) */ 1.156 +STIN void mdct_butterfly_32(DATA_TYPE *x){ 1.157 + REG_TYPE r0 = x[30] - x[14]; 1.158 + REG_TYPE r1 = x[31] - x[15]; 1.159 + 1.160 + x[30] += x[14]; 1.161 + x[31] += x[15]; 1.162 + x[14] = r0; 1.163 + x[15] = r1; 1.164 + 1.165 + r0 = x[28] - x[12]; 1.166 + r1 = x[29] - x[13]; 1.167 + x[28] += x[12]; 1.168 + x[29] += x[13]; 1.169 + x[12] = MULT_NORM( r0 * cPI1_8 - r1 * cPI3_8 ); 1.170 + x[13] = MULT_NORM( r0 * cPI3_8 + r1 * cPI1_8 ); 1.171 + 1.172 + r0 = x[26] - x[10]; 1.173 + r1 = x[27] - x[11]; 1.174 + x[26] += x[10]; 1.175 + x[27] += x[11]; 1.176 + x[10] = MULT_NORM(( r0 - r1 ) * cPI2_8); 1.177 + x[11] = MULT_NORM(( r0 + r1 ) * cPI2_8); 1.178 + 1.179 + r0 = x[24] - x[8]; 1.180 + r1 = x[25] - x[9]; 1.181 + x[24] += x[8]; 1.182 + x[25] += x[9]; 1.183 + x[8] = MULT_NORM( r0 * cPI3_8 - r1 * cPI1_8 ); 1.184 + x[9] = MULT_NORM( r1 * cPI3_8 + r0 * cPI1_8 ); 1.185 + 1.186 + r0 = x[22] - x[6]; 1.187 + r1 = x[7] - x[23]; 1.188 + x[22] += x[6]; 1.189 + x[23] += x[7]; 1.190 + x[6] = r1; 1.191 + x[7] = r0; 1.192 + 1.193 + r0 = x[4] - x[20]; 1.194 + r1 = x[5] - x[21]; 1.195 + x[20] += x[4]; 1.196 + x[21] += x[5]; 1.197 + x[4] = MULT_NORM( r1 * cPI1_8 + r0 * cPI3_8 ); 1.198 + x[5] = MULT_NORM( r1 * cPI3_8 - r0 * cPI1_8 ); 1.199 + 1.200 + r0 = x[2] - x[18]; 1.201 + r1 = x[3] - x[19]; 1.202 + x[18] += x[2]; 1.203 + x[19] += x[3]; 1.204 + x[2] = MULT_NORM(( r1 + r0 ) * cPI2_8); 1.205 + x[3] = MULT_NORM(( r1 - r0 ) * cPI2_8); 1.206 + 1.207 + r0 = x[0] - x[16]; 1.208 + r1 = x[1] - x[17]; 1.209 + x[16] += x[0]; 1.210 + x[17] += x[1]; 1.211 + x[0] = MULT_NORM( r1 * cPI3_8 + r0 * cPI1_8 ); 1.212 + x[1] = MULT_NORM( r1 * cPI1_8 - r0 * cPI3_8 ); 1.213 + 1.214 + mdct_butterfly_16(x); 1.215 + mdct_butterfly_16(x+16); 1.216 + 1.217 +} 1.218 + 1.219 +/* N point first stage butterfly (in place, 2 register) */ 1.220 +STIN void mdct_butterfly_first(DATA_TYPE *T, 1.221 + DATA_TYPE *x, 1.222 + int points){ 1.223 + 1.224 + DATA_TYPE *x1 = x + points - 8; 1.225 + DATA_TYPE *x2 = x + (points>>1) - 8; 1.226 + REG_TYPE r0; 1.227 + REG_TYPE r1; 1.228 + 1.229 + do{ 1.230 + 1.231 + r0 = x1[6] - x2[6]; 1.232 + r1 = x1[7] - x2[7]; 1.233 + x1[6] += x2[6]; 1.234 + x1[7] += x2[7]; 1.235 + x2[6] = MULT_NORM(r1 * T[1] + r0 * T[0]); 1.236 + x2[7] = MULT_NORM(r1 * T[0] - r0 * T[1]); 1.237 + 1.238 + r0 = x1[4] - x2[4]; 1.239 + r1 = x1[5] - x2[5]; 1.240 + x1[4] += x2[4]; 1.241 + x1[5] += x2[5]; 1.242 + x2[4] = MULT_NORM(r1 * T[5] + r0 * T[4]); 1.243 + x2[5] = MULT_NORM(r1 * T[4] - r0 * T[5]); 1.244 + 1.245 + r0 = x1[2] - x2[2]; 1.246 + r1 = x1[3] - x2[3]; 1.247 + x1[2] += x2[2]; 1.248 + x1[3] += x2[3]; 1.249 + x2[2] = MULT_NORM(r1 * T[9] + r0 * T[8]); 1.250 + x2[3] = MULT_NORM(r1 * T[8] - r0 * T[9]); 1.251 + 1.252 + r0 = x1[0] - x2[0]; 1.253 + r1 = x1[1] - x2[1]; 1.254 + x1[0] += x2[0]; 1.255 + x1[1] += x2[1]; 1.256 + x2[0] = MULT_NORM(r1 * T[13] + r0 * T[12]); 1.257 + x2[1] = MULT_NORM(r1 * T[12] - r0 * T[13]); 1.258 + 1.259 + x1-=8; 1.260 + x2-=8; 1.261 + T+=16; 1.262 + 1.263 + }while(x2>=x); 1.264 +} 1.265 + 1.266 +/* N/stage point generic N stage butterfly (in place, 2 register) */ 1.267 +STIN void mdct_butterfly_generic(DATA_TYPE *T, 1.268 + DATA_TYPE *x, 1.269 + int points, 1.270 + int trigint){ 1.271 + 1.272 + DATA_TYPE *x1 = x + points - 8; 1.273 + DATA_TYPE *x2 = x + (points>>1) - 8; 1.274 + REG_TYPE r0; 1.275 + REG_TYPE r1; 1.276 + 1.277 + do{ 1.278 + 1.279 + r0 = x1[6] - x2[6]; 1.280 + r1 = x1[7] - x2[7]; 1.281 + x1[6] += x2[6]; 1.282 + x1[7] += x2[7]; 1.283 + x2[6] = MULT_NORM(r1 * T[1] + r0 * T[0]); 1.284 + x2[7] = MULT_NORM(r1 * T[0] - r0 * T[1]); 1.285 + 1.286 + T+=trigint; 1.287 + 1.288 + r0 = x1[4] - x2[4]; 1.289 + r1 = x1[5] - x2[5]; 1.290 + x1[4] += x2[4]; 1.291 + x1[5] += x2[5]; 1.292 + x2[4] = MULT_NORM(r1 * T[1] + r0 * T[0]); 1.293 + x2[5] = MULT_NORM(r1 * T[0] - r0 * T[1]); 1.294 + 1.295 + T+=trigint; 1.296 + 1.297 + r0 = x1[2] - x2[2]; 1.298 + r1 = x1[3] - x2[3]; 1.299 + x1[2] += x2[2]; 1.300 + x1[3] += x2[3]; 1.301 + x2[2] = MULT_NORM(r1 * T[1] + r0 * T[0]); 1.302 + x2[3] = MULT_NORM(r1 * T[0] - r0 * T[1]); 1.303 + 1.304 + T+=trigint; 1.305 + 1.306 + r0 = x1[0] - x2[0]; 1.307 + r1 = x1[1] - x2[1]; 1.308 + x1[0] += x2[0]; 1.309 + x1[1] += x2[1]; 1.310 + x2[0] = MULT_NORM(r1 * T[1] + r0 * T[0]); 1.311 + x2[1] = MULT_NORM(r1 * T[0] - r0 * T[1]); 1.312 + 1.313 + T+=trigint; 1.314 + x1-=8; 1.315 + x2-=8; 1.316 + 1.317 + }while(x2>=x); 1.318 +} 1.319 + 1.320 +STIN void mdct_butterflies(mdct_lookup *init, 1.321 + DATA_TYPE *x, 1.322 + int points){ 1.323 + 1.324 + DATA_TYPE *T=init->trig; 1.325 + int stages=init->log2n-5; 1.326 + int i,j; 1.327 + 1.328 + if(--stages>0){ 1.329 + mdct_butterfly_first(T,x,points); 1.330 + } 1.331 + 1.332 + for(i=1;--stages>0;i++){ 1.333 + for(j=0;j<(1<<i);j++) 1.334 + mdct_butterfly_generic(T,x+(points>>i)*j,points>>i,4<<i); 1.335 + } 1.336 + 1.337 + for(j=0;j<points;j+=32) 1.338 + mdct_butterfly_32(x+j); 1.339 + 1.340 +} 1.341 + 1.342 +void mdct_clear(mdct_lookup *l){ 1.343 + if(l){ 1.344 + if(l->trig)_ogg_free(l->trig); 1.345 + if(l->bitrev)_ogg_free(l->bitrev); 1.346 + memset(l,0,sizeof(*l)); 1.347 + } 1.348 +} 1.349 + 1.350 +STIN void mdct_bitreverse(mdct_lookup *init, 1.351 + DATA_TYPE *x){ 1.352 + int n = init->n; 1.353 + int *bit = init->bitrev; 1.354 + DATA_TYPE *w0 = x; 1.355 + DATA_TYPE *w1 = x = w0+(n>>1); 1.356 + DATA_TYPE *T = init->trig+n; 1.357 + 1.358 + do{ 1.359 + DATA_TYPE *x0 = x+bit[0]; 1.360 + DATA_TYPE *x1 = x+bit[1]; 1.361 + 1.362 + REG_TYPE r0 = x0[1] - x1[1]; 1.363 + REG_TYPE r1 = x0[0] + x1[0]; 1.364 + REG_TYPE r2 = MULT_NORM(r1 * T[0] + r0 * T[1]); 1.365 + REG_TYPE r3 = MULT_NORM(r1 * T[1] - r0 * T[0]); 1.366 + 1.367 + w1 -= 4; 1.368 + 1.369 + r0 = HALVE(x0[1] + x1[1]); 1.370 + r1 = HALVE(x0[0] - x1[0]); 1.371 + 1.372 + w0[0] = r0 + r2; 1.373 + w1[2] = r0 - r2; 1.374 + w0[1] = r1 + r3; 1.375 + w1[3] = r3 - r1; 1.376 + 1.377 + x0 = x+bit[2]; 1.378 + x1 = x+bit[3]; 1.379 + 1.380 + r0 = x0[1] - x1[1]; 1.381 + r1 = x0[0] + x1[0]; 1.382 + r2 = MULT_NORM(r1 * T[2] + r0 * T[3]); 1.383 + r3 = MULT_NORM(r1 * T[3] - r0 * T[2]); 1.384 + 1.385 + r0 = HALVE(x0[1] + x1[1]); 1.386 + r1 = HALVE(x0[0] - x1[0]); 1.387 + 1.388 + w0[2] = r0 + r2; 1.389 + w1[0] = r0 - r2; 1.390 + w0[3] = r1 + r3; 1.391 + w1[1] = r3 - r1; 1.392 + 1.393 + T += 4; 1.394 + bit += 4; 1.395 + w0 += 4; 1.396 + 1.397 + }while(w0<w1); 1.398 +} 1.399 + 1.400 +void mdct_backward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out){ 1.401 + int n=init->n; 1.402 + int n2=n>>1; 1.403 + int n4=n>>2; 1.404 + 1.405 + /* rotate */ 1.406 + 1.407 + DATA_TYPE *iX = in+n2-7; 1.408 + DATA_TYPE *oX = out+n2+n4; 1.409 + DATA_TYPE *T = init->trig+n4; 1.410 + 1.411 + do{ 1.412 + oX -= 4; 1.413 + oX[0] = MULT_NORM(-iX[2] * T[3] - iX[0] * T[2]); 1.414 + oX[1] = MULT_NORM (iX[0] * T[3] - iX[2] * T[2]); 1.415 + oX[2] = MULT_NORM(-iX[6] * T[1] - iX[4] * T[0]); 1.416 + oX[3] = MULT_NORM (iX[4] * T[1] - iX[6] * T[0]); 1.417 + iX -= 8; 1.418 + T += 4; 1.419 + }while(iX>=in); 1.420 + 1.421 + iX = in+n2-8; 1.422 + oX = out+n2+n4; 1.423 + T = init->trig+n4; 1.424 + 1.425 + do{ 1.426 + T -= 4; 1.427 + oX[0] = MULT_NORM (iX[4] * T[3] + iX[6] * T[2]); 1.428 + oX[1] = MULT_NORM (iX[4] * T[2] - iX[6] * T[3]); 1.429 + oX[2] = MULT_NORM (iX[0] * T[1] + iX[2] * T[0]); 1.430 + oX[3] = MULT_NORM (iX[0] * T[0] - iX[2] * T[1]); 1.431 + iX -= 8; 1.432 + oX += 4; 1.433 + }while(iX>=in); 1.434 + 1.435 + mdct_butterflies(init,out+n2,n2); 1.436 + mdct_bitreverse(init,out); 1.437 + 1.438 + /* roatate + window */ 1.439 + 1.440 + { 1.441 + DATA_TYPE *oX1=out+n2+n4; 1.442 + DATA_TYPE *oX2=out+n2+n4; 1.443 + DATA_TYPE *iX =out; 1.444 + T =init->trig+n2; 1.445 + 1.446 + do{ 1.447 + oX1-=4; 1.448 + 1.449 + oX1[3] = MULT_NORM (iX[0] * T[1] - iX[1] * T[0]); 1.450 + oX2[0] = -MULT_NORM (iX[0] * T[0] + iX[1] * T[1]); 1.451 + 1.452 + oX1[2] = MULT_NORM (iX[2] * T[3] - iX[3] * T[2]); 1.453 + oX2[1] = -MULT_NORM (iX[2] * T[2] + iX[3] * T[3]); 1.454 + 1.455 + oX1[1] = MULT_NORM (iX[4] * T[5] - iX[5] * T[4]); 1.456 + oX2[2] = -MULT_NORM (iX[4] * T[4] + iX[5] * T[5]); 1.457 + 1.458 + oX1[0] = MULT_NORM (iX[6] * T[7] - iX[7] * T[6]); 1.459 + oX2[3] = -MULT_NORM (iX[6] * T[6] + iX[7] * T[7]); 1.460 + 1.461 + oX2+=4; 1.462 + iX += 8; 1.463 + T += 8; 1.464 + }while(iX<oX1); 1.465 + 1.466 + iX=out+n2+n4; 1.467 + oX1=out+n4; 1.468 + oX2=oX1; 1.469 + 1.470 + do{ 1.471 + oX1-=4; 1.472 + iX-=4; 1.473 + 1.474 + oX2[0] = -(oX1[3] = iX[3]); 1.475 + oX2[1] = -(oX1[2] = iX[2]); 1.476 + oX2[2] = -(oX1[1] = iX[1]); 1.477 + oX2[3] = -(oX1[0] = iX[0]); 1.478 + 1.479 + oX2+=4; 1.480 + }while(oX2<iX); 1.481 + 1.482 + iX=out+n2+n4; 1.483 + oX1=out+n2+n4; 1.484 + oX2=out+n2; 1.485 + do{ 1.486 + oX1-=4; 1.487 + oX1[0]= iX[3]; 1.488 + oX1[1]= iX[2]; 1.489 + oX1[2]= iX[1]; 1.490 + oX1[3]= iX[0]; 1.491 + iX+=4; 1.492 + }while(oX1>oX2); 1.493 + } 1.494 +} 1.495 + 1.496 +void mdct_forward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out){ 1.497 + int n=init->n; 1.498 + int n2=n>>1; 1.499 + int n4=n>>2; 1.500 + int n8=n>>3; 1.501 + DATA_TYPE *w=alloca(n*sizeof(*w)); /* forward needs working space */ 1.502 + DATA_TYPE *w2=w+n2; 1.503 + 1.504 + /* rotate */ 1.505 + 1.506 + /* window + rotate + step 1 */ 1.507 + 1.508 + REG_TYPE r0; 1.509 + REG_TYPE r1; 1.510 + DATA_TYPE *x0=in+n2+n4; 1.511 + DATA_TYPE *x1=x0+1; 1.512 + DATA_TYPE *T=init->trig+n2; 1.513 + 1.514 + int i=0; 1.515 + 1.516 + for(i=0;i<n8;i+=2){ 1.517 + x0 -=4; 1.518 + T-=2; 1.519 + r0= x0[2] + x1[0]; 1.520 + r1= x0[0] + x1[2]; 1.521 + w2[i]= MULT_NORM(r1*T[1] + r0*T[0]); 1.522 + w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]); 1.523 + x1 +=4; 1.524 + } 1.525 + 1.526 + x1=in+1; 1.527 + 1.528 + for(;i<n2-n8;i+=2){ 1.529 + T-=2; 1.530 + x0 -=4; 1.531 + r0= x0[2] - x1[0]; 1.532 + r1= x0[0] - x1[2]; 1.533 + w2[i]= MULT_NORM(r1*T[1] + r0*T[0]); 1.534 + w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]); 1.535 + x1 +=4; 1.536 + } 1.537 + 1.538 + x0=in+n; 1.539 + 1.540 + for(;i<n2;i+=2){ 1.541 + T-=2; 1.542 + x0 -=4; 1.543 + r0= -x0[2] - x1[0]; 1.544 + r1= -x0[0] - x1[2]; 1.545 + w2[i]= MULT_NORM(r1*T[1] + r0*T[0]); 1.546 + w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]); 1.547 + x1 +=4; 1.548 + } 1.549 + 1.550 + 1.551 + mdct_butterflies(init,w+n2,n2); 1.552 + mdct_bitreverse(init,w); 1.553 + 1.554 + /* roatate + window */ 1.555 + 1.556 + T=init->trig+n2; 1.557 + x0=out+n2; 1.558 + 1.559 + for(i=0;i<n4;i++){ 1.560 + x0--; 1.561 + out[i] =MULT_NORM((w[0]*T[0]+w[1]*T[1])*init->scale); 1.562 + x0[0] =MULT_NORM((w[0]*T[1]-w[1]*T[0])*init->scale); 1.563 + w+=2; 1.564 + T+=2; 1.565 + } 1.566 +}