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comparison: media/libopus/celt/mdct.c
media/libopus/celt/mdct.c
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| -1:000000000000 | 0:71368464873d |
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| 1 /* Copyright (c) 2007-2008 CSIRO | |
| 2 Copyright (c) 2007-2008 Xiph.Org Foundation | |
| 3 Written by Jean-Marc Valin */ | |
| 4 /* | |
| 5 Redistribution and use in source and binary forms, with or without | |
| 6 modification, are permitted provided that the following conditions | |
| 7 are met: | |
| 8 | |
| 9 - Redistributions of source code must retain the above copyright | |
| 10 notice, this list of conditions and the following disclaimer. | |
| 11 | |
| 12 - Redistributions in binary form must reproduce the above copyright | |
| 13 notice, this list of conditions and the following disclaimer in the | |
| 14 documentation and/or other materials provided with the distribution. | |
| 15 | |
| 16 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER | |
| 20 OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
| 21 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
| 22 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
| 23 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
| 24 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
| 25 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
| 26 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 */ | |
| 28 | |
| 29 /* This is a simple MDCT implementation that uses a N/4 complex FFT | |
| 30 to do most of the work. It should be relatively straightforward to | |
| 31 plug in pretty much and FFT here. | |
| 32 | |
| 33 This replaces the Vorbis FFT (and uses the exact same API), which | |
| 34 was a bit too messy and that was ending up duplicating code | |
| 35 (might as well use the same FFT everywhere). | |
| 36 | |
| 37 The algorithm is similar to (and inspired from) Fabrice Bellard's | |
| 38 MDCT implementation in FFMPEG, but has differences in signs, ordering | |
| 39 and scaling in many places. | |
| 40 */ | |
| 41 | |
| 42 #ifndef SKIP_CONFIG_H | |
| 43 #ifdef HAVE_CONFIG_H | |
| 44 #include "config.h" | |
| 45 #endif | |
| 46 #endif | |
| 47 | |
| 48 #include "mdct.h" | |
| 49 #include "kiss_fft.h" | |
| 50 #include "_kiss_fft_guts.h" | |
| 51 #include <math.h> | |
| 52 #include "os_support.h" | |
| 53 #include "mathops.h" | |
| 54 #include "stack_alloc.h" | |
| 55 | |
| 56 #ifdef CUSTOM_MODES | |
| 57 | |
| 58 int clt_mdct_init(mdct_lookup *l,int N, int maxshift) | |
| 59 { | |
| 60 int i; | |
| 61 int N4; | |
| 62 kiss_twiddle_scalar *trig; | |
| 63 #if defined(FIXED_POINT) | |
| 64 int N2=N>>1; | |
| 65 #endif | |
| 66 l->n = N; | |
| 67 N4 = N>>2; | |
| 68 l->maxshift = maxshift; | |
| 69 for (i=0;i<=maxshift;i++) | |
| 70 { | |
| 71 if (i==0) | |
| 72 l->kfft[i] = opus_fft_alloc(N>>2>>i, 0, 0); | |
| 73 else | |
| 74 l->kfft[i] = opus_fft_alloc_twiddles(N>>2>>i, 0, 0, l->kfft[0]); | |
| 75 #ifndef ENABLE_TI_DSPLIB55 | |
| 76 if (l->kfft[i]==NULL) | |
| 77 return 0; | |
| 78 #endif | |
| 79 } | |
| 80 l->trig = trig = (kiss_twiddle_scalar*)opus_alloc((N4+1)*sizeof(kiss_twiddle_scalar)); | |
| 81 if (l->trig==NULL) | |
| 82 return 0; | |
| 83 /* We have enough points that sine isn't necessary */ | |
| 84 #if defined(FIXED_POINT) | |
| 85 for (i=0;i<=N4;i++) | |
| 86 trig[i] = TRIG_UPSCALE*celt_cos_norm(DIV32(ADD32(SHL32(EXTEND32(i),17),N2),N)); | |
| 87 #else | |
| 88 for (i=0;i<=N4;i++) | |
| 89 trig[i] = (kiss_twiddle_scalar)cos(2*PI*i/N); | |
| 90 #endif | |
| 91 return 1; | |
| 92 } | |
| 93 | |
| 94 void clt_mdct_clear(mdct_lookup *l) | |
| 95 { | |
| 96 int i; | |
| 97 for (i=0;i<=l->maxshift;i++) | |
| 98 opus_fft_free(l->kfft[i]); | |
| 99 opus_free((kiss_twiddle_scalar*)l->trig); | |
| 100 } | |
| 101 | |
| 102 #endif /* CUSTOM_MODES */ | |
| 103 | |
| 104 /* Forward MDCT trashes the input array */ | |
| 105 void clt_mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out, | |
| 106 const opus_val16 *window, int overlap, int shift, int stride) | |
| 107 { | |
| 108 int i; | |
| 109 int N, N2, N4; | |
| 110 kiss_twiddle_scalar sine; | |
| 111 VARDECL(kiss_fft_scalar, f); | |
| 112 VARDECL(kiss_fft_scalar, f2); | |
| 113 SAVE_STACK; | |
| 114 N = l->n; | |
| 115 N >>= shift; | |
| 116 N2 = N>>1; | |
| 117 N4 = N>>2; | |
| 118 ALLOC(f, N2, kiss_fft_scalar); | |
| 119 ALLOC(f2, N2, kiss_fft_scalar); | |
| 120 /* sin(x) ~= x here */ | |
| 121 #ifdef FIXED_POINT | |
| 122 sine = TRIG_UPSCALE*(QCONST16(0.7853981f, 15)+N2)/N; | |
| 123 #else | |
| 124 sine = (kiss_twiddle_scalar)2*PI*(.125f)/N; | |
| 125 #endif | |
| 126 | |
| 127 /* Consider the input to be composed of four blocks: [a, b, c, d] */ | |
| 128 /* Window, shuffle, fold */ | |
| 129 { | |
| 130 /* Temp pointers to make it really clear to the compiler what we're doing */ | |
| 131 const kiss_fft_scalar * OPUS_RESTRICT xp1 = in+(overlap>>1); | |
| 132 const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+N2-1+(overlap>>1); | |
| 133 kiss_fft_scalar * OPUS_RESTRICT yp = f; | |
| 134 const opus_val16 * OPUS_RESTRICT wp1 = window+(overlap>>1); | |
| 135 const opus_val16 * OPUS_RESTRICT wp2 = window+(overlap>>1)-1; | |
| 136 for(i=0;i<((overlap+3)>>2);i++) | |
| 137 { | |
| 138 /* Real part arranged as -d-cR, Imag part arranged as -b+aR*/ | |
| 139 *yp++ = MULT16_32_Q15(*wp2, xp1[N2]) + MULT16_32_Q15(*wp1,*xp2); | |
| 140 *yp++ = MULT16_32_Q15(*wp1, *xp1) - MULT16_32_Q15(*wp2, xp2[-N2]); | |
| 141 xp1+=2; | |
| 142 xp2-=2; | |
| 143 wp1+=2; | |
| 144 wp2-=2; | |
| 145 } | |
| 146 wp1 = window; | |
| 147 wp2 = window+overlap-1; | |
| 148 for(;i<N4-((overlap+3)>>2);i++) | |
| 149 { | |
| 150 /* Real part arranged as a-bR, Imag part arranged as -c-dR */ | |
| 151 *yp++ = *xp2; | |
| 152 *yp++ = *xp1; | |
| 153 xp1+=2; | |
| 154 xp2-=2; | |
| 155 } | |
| 156 for(;i<N4;i++) | |
| 157 { | |
| 158 /* Real part arranged as a-bR, Imag part arranged as -c-dR */ | |
| 159 *yp++ = -MULT16_32_Q15(*wp1, xp1[-N2]) + MULT16_32_Q15(*wp2, *xp2); | |
| 160 *yp++ = MULT16_32_Q15(*wp2, *xp1) + MULT16_32_Q15(*wp1, xp2[N2]); | |
| 161 xp1+=2; | |
| 162 xp2-=2; | |
| 163 wp1+=2; | |
| 164 wp2-=2; | |
| 165 } | |
| 166 } | |
| 167 /* Pre-rotation */ | |
| 168 { | |
| 169 kiss_fft_scalar * OPUS_RESTRICT yp = f; | |
| 170 const kiss_twiddle_scalar *t = &l->trig[0]; | |
| 171 for(i=0;i<N4;i++) | |
| 172 { | |
| 173 kiss_fft_scalar re, im, yr, yi; | |
| 174 re = yp[0]; | |
| 175 im = yp[1]; | |
| 176 yr = -S_MUL(re,t[i<<shift]) - S_MUL(im,t[(N4-i)<<shift]); | |
| 177 yi = -S_MUL(im,t[i<<shift]) + S_MUL(re,t[(N4-i)<<shift]); | |
| 178 /* works because the cos is nearly one */ | |
| 179 *yp++ = yr + S_MUL(yi,sine); | |
| 180 *yp++ = yi - S_MUL(yr,sine); | |
| 181 } | |
| 182 } | |
| 183 | |
| 184 /* N/4 complex FFT, down-scales by 4/N */ | |
| 185 opus_fft(l->kfft[shift], (kiss_fft_cpx *)f, (kiss_fft_cpx *)f2); | |
| 186 | |
| 187 /* Post-rotate */ | |
| 188 { | |
| 189 /* Temp pointers to make it really clear to the compiler what we're doing */ | |
| 190 const kiss_fft_scalar * OPUS_RESTRICT fp = f2; | |
| 191 kiss_fft_scalar * OPUS_RESTRICT yp1 = out; | |
| 192 kiss_fft_scalar * OPUS_RESTRICT yp2 = out+stride*(N2-1); | |
| 193 const kiss_twiddle_scalar *t = &l->trig[0]; | |
| 194 /* Temp pointers to make it really clear to the compiler what we're doing */ | |
| 195 for(i=0;i<N4;i++) | |
| 196 { | |
| 197 kiss_fft_scalar yr, yi; | |
| 198 yr = S_MUL(fp[1],t[(N4-i)<<shift]) + S_MUL(fp[0],t[i<<shift]); | |
| 199 yi = S_MUL(fp[0],t[(N4-i)<<shift]) - S_MUL(fp[1],t[i<<shift]); | |
| 200 /* works because the cos is nearly one */ | |
| 201 *yp1 = yr - S_MUL(yi,sine); | |
| 202 *yp2 = yi + S_MUL(yr,sine);; | |
| 203 fp += 2; | |
| 204 yp1 += 2*stride; | |
| 205 yp2 -= 2*stride; | |
| 206 } | |
| 207 } | |
| 208 RESTORE_STACK; | |
| 209 } | |
| 210 | |
| 211 void clt_mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out, | |
| 212 const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride) | |
| 213 { | |
| 214 int i; | |
| 215 int N, N2, N4; | |
| 216 kiss_twiddle_scalar sine; | |
| 217 VARDECL(kiss_fft_scalar, f2); | |
| 218 SAVE_STACK; | |
| 219 N = l->n; | |
| 220 N >>= shift; | |
| 221 N2 = N>>1; | |
| 222 N4 = N>>2; | |
| 223 ALLOC(f2, N2, kiss_fft_scalar); | |
| 224 /* sin(x) ~= x here */ | |
| 225 #ifdef FIXED_POINT | |
| 226 sine = TRIG_UPSCALE*(QCONST16(0.7853981f, 15)+N2)/N; | |
| 227 #else | |
| 228 sine = (kiss_twiddle_scalar)2*PI*(.125f)/N; | |
| 229 #endif | |
| 230 | |
| 231 /* Pre-rotate */ | |
| 232 { | |
| 233 /* Temp pointers to make it really clear to the compiler what we're doing */ | |
| 234 const kiss_fft_scalar * OPUS_RESTRICT xp1 = in; | |
| 235 const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+stride*(N2-1); | |
| 236 kiss_fft_scalar * OPUS_RESTRICT yp = f2; | |
| 237 const kiss_twiddle_scalar *t = &l->trig[0]; | |
| 238 for(i=0;i<N4;i++) | |
| 239 { | |
| 240 kiss_fft_scalar yr, yi; | |
| 241 yr = -S_MUL(*xp2, t[i<<shift]) + S_MUL(*xp1,t[(N4-i)<<shift]); | |
| 242 yi = -S_MUL(*xp2, t[(N4-i)<<shift]) - S_MUL(*xp1,t[i<<shift]); | |
| 243 /* works because the cos is nearly one */ | |
| 244 *yp++ = yr - S_MUL(yi,sine); | |
| 245 *yp++ = yi + S_MUL(yr,sine); | |
| 246 xp1+=2*stride; | |
| 247 xp2-=2*stride; | |
| 248 } | |
| 249 } | |
| 250 | |
| 251 /* Inverse N/4 complex FFT. This one should *not* downscale even in fixed-point */ | |
| 252 opus_ifft(l->kfft[shift], (kiss_fft_cpx *)f2, (kiss_fft_cpx *)(out+(overlap>>1))); | |
| 253 | |
| 254 /* Post-rotate and de-shuffle from both ends of the buffer at once to make | |
| 255 it in-place. */ | |
| 256 { | |
| 257 kiss_fft_scalar * OPUS_RESTRICT yp0 = out+(overlap>>1); | |
| 258 kiss_fft_scalar * OPUS_RESTRICT yp1 = out+(overlap>>1)+N2-2; | |
| 259 const kiss_twiddle_scalar *t = &l->trig[0]; | |
| 260 /* Loop to (N4+1)>>1 to handle odd N4. When N4 is odd, the | |
| 261 middle pair will be computed twice. */ | |
| 262 for(i=0;i<(N4+1)>>1;i++) | |
| 263 { | |
| 264 kiss_fft_scalar re, im, yr, yi; | |
| 265 kiss_twiddle_scalar t0, t1; | |
| 266 re = yp0[0]; | |
| 267 im = yp0[1]; | |
| 268 t0 = t[i<<shift]; | |
| 269 t1 = t[(N4-i)<<shift]; | |
| 270 /* We'd scale up by 2 here, but instead it's done when mixing the windows */ | |
| 271 yr = S_MUL(re,t0) - S_MUL(im,t1); | |
| 272 yi = S_MUL(im,t0) + S_MUL(re,t1); | |
| 273 re = yp1[0]; | |
| 274 im = yp1[1]; | |
| 275 /* works because the cos is nearly one */ | |
| 276 yp0[0] = -(yr - S_MUL(yi,sine)); | |
| 277 yp1[1] = yi + S_MUL(yr,sine); | |
| 278 | |
| 279 t0 = t[(N4-i-1)<<shift]; | |
| 280 t1 = t[(i+1)<<shift]; | |
| 281 /* We'd scale up by 2 here, but instead it's done when mixing the windows */ | |
| 282 yr = S_MUL(re,t0) - S_MUL(im,t1); | |
| 283 yi = S_MUL(im,t0) + S_MUL(re,t1); | |
| 284 /* works because the cos is nearly one */ | |
| 285 yp1[0] = -(yr - S_MUL(yi,sine)); | |
| 286 yp0[1] = yi + S_MUL(yr,sine); | |
| 287 yp0 += 2; | |
| 288 yp1 -= 2; | |
| 289 } | |
| 290 } | |
| 291 | |
| 292 /* Mirror on both sides for TDAC */ | |
| 293 { | |
| 294 kiss_fft_scalar * OPUS_RESTRICT xp1 = out+overlap-1; | |
| 295 kiss_fft_scalar * OPUS_RESTRICT yp1 = out; | |
| 296 const opus_val16 * OPUS_RESTRICT wp1 = window; | |
| 297 const opus_val16 * OPUS_RESTRICT wp2 = window+overlap-1; | |
| 298 | |
| 299 for(i = 0; i < overlap/2; i++) | |
| 300 { | |
| 301 kiss_fft_scalar x1, x2; | |
| 302 x1 = *xp1; | |
| 303 x2 = *yp1; | |
| 304 *yp1++ = MULT16_32_Q15(*wp2, x2) - MULT16_32_Q15(*wp1, x1); | |
| 305 *xp1-- = MULT16_32_Q15(*wp1, x2) + MULT16_32_Q15(*wp2, x1); | |
| 306 wp1++; | |
| 307 wp2--; | |
| 308 } | |
| 309 } | |
| 310 RESTORE_STACK; | |
| 311 } |
