| /******************************************************************** |
| * * |
| * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. * |
| * * |
| * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * |
| * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * |
| * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * |
| * * |
| * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003 * |
| * BY THE Xiph.Org FOUNDATION http://www.xiph.org/ * |
| * * |
| ******************************************************************** |
| |
| function: normalized modified discrete cosine transform |
| power of two length transform only [64 <= n ] |
| last mod: $Id: mdct.c,v 1.9.6.5 2003/04/29 04:03:27 xiphmont Exp $ |
| |
| Original algorithm adapted long ago from _The use of multirate filter |
| banks for coding of high quality digital audio_, by T. Sporer, |
| K. Brandenburg and B. Edler, collection of the European Signal |
| Processing Conference (EUSIPCO), Amsterdam, June 1992, Vol.1, pp |
| 211-214 |
| |
| The below code implements an algorithm that no longer looks much like |
| that presented in the paper, but the basic structure remains if you |
| dig deep enough to see it. |
| |
| This module DOES NOT INCLUDE code to generate/apply the window |
| function. Everybody has their own weird favorite including me... I |
| happen to like the properties of y=sin(.5PI*sin^2(x)), but others may |
| vehemently disagree. |
| |
| ********************************************************************/ |
| |
| #include "ivorbiscodec.h" |
| #include "os.h" |
| #include "misc.h" |
| #include "mdct.h" |
| #include "mdct_lookup.h" |
| |
| STIN void presymmetry(DATA_TYPE *in,int n2,int step){ |
| DATA_TYPE *aX; |
| DATA_TYPE *bX; |
| LOOKUP_T *T; |
| int n4=n2>>1; |
| |
| aX = in+n2-3; |
| T = sincos_lookup0; |
| |
| do{ |
| REG_TYPE r0= aX[0]; |
| REG_TYPE r2= aX[2]; |
| XPROD31( r0, r2, T[0], T[1], &aX[0], &aX[2] ); T+=step; |
| aX-=4; |
| }while(aX>=in+n4); |
| do{ |
| REG_TYPE r0= aX[0]; |
| REG_TYPE r2= aX[2]; |
| XPROD31( r0, r2, T[1], T[0], &aX[0], &aX[2] ); T-=step; |
| aX-=4; |
| }while(aX>=in); |
| |
| aX = in+n2-4; |
| bX = in; |
| T = sincos_lookup0; |
| do{ |
| REG_TYPE ri0= aX[0]; |
| REG_TYPE ri2= aX[2]; |
| REG_TYPE ro0= bX[0]; |
| REG_TYPE ro2= bX[2]; |
| |
| XNPROD31( ro2, ro0, T[1], T[0], &aX[0], &aX[2] ); T+=step; |
| XNPROD31( ri2, ri0, T[0], T[1], &bX[0], &bX[2] ); |
| |
| aX-=4; |
| bX+=4; |
| }while(aX>=in+n4); |
| |
| } |
| |
| /* 8 point butterfly (in place) */ |
| STIN void mdct_butterfly_8(DATA_TYPE *x){ |
| |
| REG_TYPE r0 = x[0] + x[1]; |
| REG_TYPE r1 = x[0] - x[1]; |
| REG_TYPE r2 = x[2] + x[3]; |
| REG_TYPE r3 = x[2] - x[3]; |
| REG_TYPE r4 = x[4] + x[5]; |
| REG_TYPE r5 = x[4] - x[5]; |
| REG_TYPE r6 = x[6] + x[7]; |
| REG_TYPE r7 = x[6] - x[7]; |
| |
| x[0] = r5 + r3; |
| x[1] = r7 - r1; |
| x[2] = r5 - r3; |
| x[3] = r7 + r1; |
| x[4] = r4 - r0; |
| x[5] = r6 - r2; |
| x[6] = r4 + r0; |
| x[7] = r6 + r2; |
| MB(); |
| } |
| |
| /* 16 point butterfly (in place, 4 register) */ |
| STIN void mdct_butterfly_16(DATA_TYPE *x){ |
| |
| REG_TYPE r0, r1, r2, r3; |
| |
| r0 = x[ 8] - x[ 9]; x[ 8] += x[ 9]; |
| r1 = x[10] - x[11]; x[10] += x[11]; |
| r2 = x[ 1] - x[ 0]; x[ 9] = x[ 1] + x[0]; |
| r3 = x[ 3] - x[ 2]; x[11] = x[ 3] + x[2]; |
| x[ 0] = MULT31((r0 - r1) , cPI2_8); |
| x[ 1] = MULT31((r2 + r3) , cPI2_8); |
| x[ 2] = MULT31((r0 + r1) , cPI2_8); |
| x[ 3] = MULT31((r3 - r2) , cPI2_8); |
| MB(); |
| |
| r2 = x[12] - x[13]; x[12] += x[13]; |
| r3 = x[14] - x[15]; x[14] += x[15]; |
| r0 = x[ 4] - x[ 5]; x[13] = x[ 5] + x[ 4]; |
| r1 = x[ 7] - x[ 6]; x[15] = x[ 7] + x[ 6]; |
| x[ 4] = r2; x[ 5] = r1; |
| x[ 6] = r3; x[ 7] = r0; |
| MB(); |
| |
| mdct_butterfly_8(x); |
| mdct_butterfly_8(x+8); |
| } |
| |
| /* 32 point butterfly (in place, 4 register) */ |
| STIN void mdct_butterfly_32(DATA_TYPE *x){ |
| |
| REG_TYPE r0, r1, r2, r3; |
| |
| r0 = x[16] - x[17]; x[16] += x[17]; |
| r1 = x[18] - x[19]; x[18] += x[19]; |
| r2 = x[ 1] - x[ 0]; x[17] = x[ 1] + x[ 0]; |
| r3 = x[ 3] - x[ 2]; x[19] = x[ 3] + x[ 2]; |
| XNPROD31( r0, r1, cPI3_8, cPI1_8, &x[ 0], &x[ 2] ); |
| XPROD31 ( r2, r3, cPI1_8, cPI3_8, &x[ 1], &x[ 3] ); |
| MB(); |
| |
| r0 = x[20] - x[21]; x[20] += x[21]; |
| r1 = x[22] - x[23]; x[22] += x[23]; |
| r2 = x[ 5] - x[ 4]; x[21] = x[ 5] + x[ 4]; |
| r3 = x[ 7] - x[ 6]; x[23] = x[ 7] + x[ 6]; |
| x[ 4] = MULT31((r0 - r1) , cPI2_8); |
| x[ 5] = MULT31((r3 + r2) , cPI2_8); |
| x[ 6] = MULT31((r0 + r1) , cPI2_8); |
| x[ 7] = MULT31((r3 - r2) , cPI2_8); |
| MB(); |
| |
| r0 = x[24] - x[25]; x[24] += x[25]; |
| r1 = x[26] - x[27]; x[26] += x[27]; |
| r2 = x[ 9] - x[ 8]; x[25] = x[ 9] + x[ 8]; |
| r3 = x[11] - x[10]; x[27] = x[11] + x[10]; |
| XNPROD31( r0, r1, cPI1_8, cPI3_8, &x[ 8], &x[10] ); |
| XPROD31 ( r2, r3, cPI3_8, cPI1_8, &x[ 9], &x[11] ); |
| MB(); |
| |
| r0 = x[28] - x[29]; x[28] += x[29]; |
| r1 = x[30] - x[31]; x[30] += x[31]; |
| r2 = x[12] - x[13]; x[29] = x[13] + x[12]; |
| r3 = x[15] - x[14]; x[31] = x[15] + x[14]; |
| x[12] = r0; x[13] = r3; |
| x[14] = r1; x[15] = r2; |
| MB(); |
| |
| mdct_butterfly_16(x); |
| mdct_butterfly_16(x+16); |
| } |
| |
| /* N/stage point generic N stage butterfly (in place, 2 register) */ |
| STIN void mdct_butterfly_generic(DATA_TYPE *x,int points,int step){ |
| |
| LOOKUP_T *T = sincos_lookup0; |
| DATA_TYPE *x1 = x + points - 4; |
| DATA_TYPE *x2 = x + (points>>1) - 4; |
| REG_TYPE r0, r1, r2, r3; |
| |
| do{ |
| r0 = x1[0] - x1[1]; x1[0] += x1[1]; |
| r1 = x1[3] - x1[2]; x1[2] += x1[3]; |
| r2 = x2[1] - x2[0]; x1[1] = x2[1] + x2[0]; |
| r3 = x2[3] - x2[2]; x1[3] = x2[3] + x2[2]; |
| XPROD31( r1, r0, T[0], T[1], &x2[0], &x2[2] ); |
| XPROD31( r2, r3, T[0], T[1], &x2[1], &x2[3] ); T+=step; |
| x1-=4; |
| x2-=4; |
| }while(T<sincos_lookup0+1024); |
| do{ |
| r0 = x1[0] - x1[1]; x1[0] += x1[1]; |
| r1 = x1[2] - x1[3]; x1[2] += x1[3]; |
| r2 = x2[0] - x2[1]; x1[1] = x2[1] + x2[0]; |
| r3 = x2[3] - x2[2]; x1[3] = x2[3] + x2[2]; |
| XNPROD31( r0, r1, T[0], T[1], &x2[0], &x2[2] ); |
| XNPROD31( r3, r2, T[0], T[1], &x2[1], &x2[3] ); T-=step; |
| x1-=4; |
| x2-=4; |
| }while(T>sincos_lookup0); |
| } |
| |
| STIN void mdct_butterflies(DATA_TYPE *x,int points,int shift){ |
| |
| int stages=8-shift; |
| int i,j; |
| |
| for(i=0;--stages>0;i++){ |
| for(j=0;j<(1<<i);j++) |
| mdct_butterfly_generic(x+(points>>i)*j,points>>i,4<<(i+shift)); |
| } |
| |
| for(j=0;j<points;j+=32) |
| mdct_butterfly_32(x+j); |
| } |
| |
| static unsigned char bitrev[16]={0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15}; |
| |
| STIN int bitrev12(int x){ |
| return bitrev[x>>8]|(bitrev[(x&0x0f0)>>4]<<4)|(((int)bitrev[x&0x00f])<<8); |
| } |
| |
| STIN void mdct_bitreverse(DATA_TYPE *x,int n,int shift){ |
| int bit = 0; |
| DATA_TYPE *w = x+(n>>1); |
| |
| do{ |
| DATA_TYPE b = bitrev12(bit++); |
| DATA_TYPE *xx = x + (b>>shift); |
| REG_TYPE r; |
| |
| w -= 2; |
| |
| if(w>xx){ |
| |
| r = xx[0]; |
| xx[0] = w[0]; |
| w[0] = r; |
| |
| r = xx[1]; |
| xx[1] = w[1]; |
| w[1] = r; |
| } |
| }while(w>x); |
| } |
| |
| STIN void mdct_step7(DATA_TYPE *x,int n,int step){ |
| DATA_TYPE *w0 = x; |
| DATA_TYPE *w1 = x+(n>>1); |
| LOOKUP_T *T = (step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1; |
| LOOKUP_T *Ttop = T+1024; |
| REG_TYPE r0, r1, r2, r3; |
| |
| do{ |
| w1 -= 2; |
| |
| r0 = w0[0] + w1[0]; |
| r1 = w1[1] - w0[1]; |
| r2 = MULT32(r0, T[1]) + MULT32(r1, T[0]); |
| r3 = MULT32(r1, T[1]) - MULT32(r0, T[0]); |
| T+=step; |
| |
| r0 = (w0[1] + w1[1])>>1; |
| r1 = (w0[0] - w1[0])>>1; |
| w0[0] = r0 + r2; |
| w0[1] = r1 + r3; |
| w1[0] = r0 - r2; |
| w1[1] = r3 - r1; |
| |
| w0 += 2; |
| }while(T<Ttop); |
| do{ |
| w1 -= 2; |
| |
| r0 = w0[0] + w1[0]; |
| r1 = w1[1] - w0[1]; |
| T-=step; |
| r2 = MULT32(r0, T[0]) + MULT32(r1, T[1]); |
| r3 = MULT32(r1, T[0]) - MULT32(r0, T[1]); |
| |
| r0 = (w0[1] + w1[1])>>1; |
| r1 = (w0[0] - w1[0])>>1; |
| w0[0] = r0 + r2; |
| w0[1] = r1 + r3; |
| w1[0] = r0 - r2; |
| w1[1] = r3 - r1; |
| |
| w0 += 2; |
| }while(w0<w1); |
| } |
| |
| STIN void mdct_step8(DATA_TYPE *x, int n, int step){ |
| LOOKUP_T *T; |
| LOOKUP_T *V; |
| DATA_TYPE *iX =x+(n>>1); |
| step>>=2; |
| |
| switch(step) { |
| default: |
| T=(step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1; |
| do{ |
| REG_TYPE r0 = x[0]; |
| REG_TYPE r1 = -x[1]; |
| XPROD31( r0, r1, T[0], T[1], x, x+1); T+=step; |
| x +=2; |
| }while(x<iX); |
| break; |
| |
| case 1: |
| { |
| /* linear interpolation between table values: offset=0.5, step=1 */ |
| REG_TYPE t0,t1,v0,v1,r0,r1; |
| T = sincos_lookup0; |
| V = sincos_lookup1; |
| t0 = (*T++)>>1; |
| t1 = (*T++)>>1; |
| do{ |
| r0 = x[0]; |
| r1 = -x[1]; |
| t0 += (v0 = (*V++)>>1); |
| t1 += (v1 = (*V++)>>1); |
| XPROD31( r0, r1, t0, t1, x, x+1 ); |
| |
| r0 = x[2]; |
| r1 = -x[3]; |
| v0 += (t0 = (*T++)>>1); |
| v1 += (t1 = (*T++)>>1); |
| XPROD31( r0, r1, v0, v1, x+2, x+3 ); |
| |
| x += 4; |
| }while(x<iX); |
| break; |
| } |
| |
| case 0: |
| { |
| /* linear interpolation between table values: offset=0.25, step=0.5 */ |
| REG_TYPE t0,t1,v0,v1,q0,q1,r0,r1; |
| T = sincos_lookup0; |
| V = sincos_lookup1; |
| t0 = *T++; |
| t1 = *T++; |
| do{ |
| |
| |
| v0 = *V++; |
| v1 = *V++; |
| t0 += (q0 = (v0-t0)>>2); |
| t1 += (q1 = (v1-t1)>>2); |
| r0 = x[0]; |
| r1 = -x[1]; |
| XPROD31( r0, r1, t0, t1, x, x+1 ); |
| t0 = v0-q0; |
| t1 = v1-q1; |
| r0 = x[2]; |
| r1 = -x[3]; |
| XPROD31( r0, r1, t0, t1, x+2, x+3 ); |
| |
| t0 = *T++; |
| t1 = *T++; |
| v0 += (q0 = (t0-v0)>>2); |
| v1 += (q1 = (t1-v1)>>2); |
| r0 = x[4]; |
| r1 = -x[5]; |
| XPROD31( r0, r1, v0, v1, x+4, x+5 ); |
| v0 = t0-q0; |
| v1 = t1-q1; |
| r0 = x[6]; |
| r1 = -x[7]; |
| XPROD31( r0, r1, v0, v1, x+5, x+6 ); |
| |
| x+=8; |
| }while(x<iX); |
| break; |
| } |
| } |
| } |
| |
| /* partial; doesn't perform last-step deinterleave/unrolling. That |
| can be done more efficiently during pcm output */ |
| void mdct_backward(int n, DATA_TYPE *in){ |
| int shift; |
| int step; |
| |
| for (shift=4;!(n&(1<<shift));shift++); |
| shift=13-shift; |
| step=2<<shift; |
| |
| presymmetry(in,n>>1,step); |
| mdct_butterflies(in,n>>1,shift); |
| mdct_bitreverse(in,n,shift); |
| mdct_step7(in,n,step); |
| mdct_step8(in,n,step); |
| } |
| |
| void mdct_shift_right(int n, DATA_TYPE *in, DATA_TYPE *right){ |
| int i; |
| n>>=2; |
| in+=1; |
| |
| for(i=0;i<n;i++) |
| right[i]=in[i<<1]; |
| } |
| |
| void mdct_unroll_lap(int n0,int n1, |
| int lW,int W, |
| DATA_TYPE *in, |
| DATA_TYPE *right, |
| LOOKUP_T *w0, |
| LOOKUP_T *w1, |
| ogg_int16_t *out, |
| int step, |
| int start, /* samples, this frame */ |
| int end /* samples, this frame */){ |
| |
| DATA_TYPE *l=in+(W&&lW ? n1>>1 : n0>>1); |
| DATA_TYPE *r=right+(lW ? n1>>2 : n0>>2); |
| DATA_TYPE *post; |
| LOOKUP_T *wR=(W && lW ? w1+(n1>>1) : w0+(n0>>1)); |
| LOOKUP_T *wL=(W && lW ? w1 : w0 ); |
| |
| int preLap=(lW && !W ? (n1>>2)-(n0>>2) : 0 ); |
| int halfLap=(lW && W ? (n1>>2) : (n0>>2) ); |
| int postLap=(!lW && W ? (n1>>2)-(n0>>2) : 0 ); |
| int n,off; |
| |
| /* preceeding direct-copy lapping from previous frame, if any */ |
| if(preLap){ |
| n = (end<preLap?end:preLap); |
| off = (start<preLap?start:preLap); |
| post = r-n; |
| r -= off; |
| start -= off; |
| end -= n; |
| while(r>post){ |
| *out = CLIP_TO_15((*--r)>>9); |
| out+=step; |
| } |
| } |
| |
| /* cross-lap; two halves due to wrap-around */ |
| n = (end<halfLap?end:halfLap); |
| off = (start<halfLap?start:halfLap); |
| post = r-n; |
| r -= off; |
| l -= off*2; |
| start -= off; |
| wR -= off; |
| wL += off; |
| end -= n; |
| while(r>post){ |
| l-=2; |
| *out = CLIP_TO_15((MULT31(*--r,*--wR) + MULT31(*l,*wL++))>>9); |
| out+=step; |
| } |
| |
| n = (end<halfLap?end:halfLap); |
| off = (start<halfLap?start:halfLap); |
| post = r+n; |
| r += off; |
| l += off*2; |
| start -= off; |
| end -= n; |
| wR -= off; |
| wL += off; |
| while(r<post){ |
| *out = CLIP_TO_15((MULT31(*r++,*--wR) - MULT31(*l,*wL++))>>9); |
| out+=step; |
| l+=2; |
| } |
| |
| /* preceeding direct-copy lapping from previous frame, if any */ |
| if(postLap){ |
| n = (end<postLap?end:postLap); |
| off = (start<postLap?start:postLap); |
| post = l+n*2; |
| l += off*2; |
| while(l<post){ |
| *out = CLIP_TO_15((-*l)>>9); |
| out+=step; |
| l+=2; |
| } |
| } |
| } |
| |
