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/*
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 * Floating point AAN IDCT
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 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "faanidct.h"
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/* To allow switching to double. */
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#define FLOAT float
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#define B0 1.0000000000000000000000
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#define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
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#define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
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#define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
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#define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
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#define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
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#define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
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#define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
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#define A4 0.70710678118654752438 // cos(pi*4/16)
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#define A2 0.92387953251128675613 // cos(pi*2/16)
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static const FLOAT prescale[64]={
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B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
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B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
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B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
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B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
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B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
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B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
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B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
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B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
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};
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static inline void p8idct(DCTELEM data[64], FLOAT temp[64], uint8_t *dest, int stride, int x, int y, int type){
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    int i;
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    FLOAT av_unused tmp0;
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    FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
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    FLOAT os07, os16, os25, os34;
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    FLOAT od07, od16, od25, od34;
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    for(i=0; i<y*8; i+=y){
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        s17= temp[1*x + i] + temp[7*x + i];
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        d17= temp[1*x + i] - temp[7*x + i];
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        s53= temp[5*x + i] + temp[3*x + i];
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        d53= temp[5*x + i] - temp[3*x + i];
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        od07=  s17 + s53;
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        od25= (s17 - s53)*(2*A4);
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#if 0 //these 2 are equivalent
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        tmp0= (d17 + d53)*(2*A2);
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        od34=  d17*( 2*B6) - tmp0;
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        od16=  d53*(-2*B2) + tmp0;
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#else
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        od34=  d17*(2*(B6-A2)) - d53*(2*A2);
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        od16=  d53*(2*(A2-B2)) + d17*(2*A2);
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#endif
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        od16 -= od07;
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        od25 -= od16;
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        od34 += od25;
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        s26 = temp[2*x + i] + temp[6*x + i];
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        d26 = temp[2*x + i] - temp[6*x + i];
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        d26*= 2*A4;
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        d26-= s26;
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        s04= temp[0*x + i] + temp[4*x + i];
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        d04= temp[0*x + i] - temp[4*x + i];
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        os07= s04 + s26;
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        os34= s04 - s26;
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        os16= d04 + d26;
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        os25= d04 - d26;
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        if(type==0){
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            temp[0*x + i]= os07 + od07;
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            temp[7*x + i]= os07 - od07;
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            temp[1*x + i]= os16 + od16;
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            temp[6*x + i]= os16 - od16;
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            temp[2*x + i]= os25 + od25;
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            temp[5*x + i]= os25 - od25;
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            temp[3*x + i]= os34 - od34;
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            temp[4*x + i]= os34 + od34;
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        }else if(type==1){
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            data[0*x + i]= lrintf(os07 + od07);
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            data[7*x + i]= lrintf(os07 - od07);
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            data[1*x + i]= lrintf(os16 + od16);
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            data[6*x + i]= lrintf(os16 - od16);
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            data[2*x + i]= lrintf(os25 + od25);
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            data[5*x + i]= lrintf(os25 - od25);
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            data[3*x + i]= lrintf(os34 - od34);
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            data[4*x + i]= lrintf(os34 + od34);
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        }else if(type==2){
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            dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
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            dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
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            dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
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            dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
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            dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
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            dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
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            dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
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            dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
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        }else{
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            dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
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            dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
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            dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
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            dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
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            dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
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            dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
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            dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
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            dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
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        }
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    }
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}
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void ff_faanidct(DCTELEM block[64]){
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    FLOAT temp[64];
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    int i;
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    emms_c();
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    for(i=0; i<64; i++)
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        temp[i] = block[i] * prescale[i];
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    p8idct(block, temp, NULL, 0, 1, 8, 0);
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    p8idct(block, temp, NULL, 0, 8, 1, 1);
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}
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void ff_faanidct_add(uint8_t *dest, int line_size, DCTELEM block[64]){
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    FLOAT temp[64];
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    int i;
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    emms_c();
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    for(i=0; i<64; i++)
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        temp[i] = block[i] * prescale[i];
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    p8idct(block, temp, NULL,         0, 1, 8, 0);
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    p8idct(NULL , temp, dest, line_size, 8, 1, 2);
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}
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void ff_faanidct_put(uint8_t *dest, int line_size, DCTELEM block[64]){
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    FLOAT temp[64];
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    int i;
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    emms_c();
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    for(i=0; i<64; i++)
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        temp[i] = block[i] * prescale[i];
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    p8idct(block, temp, NULL,         0, 1, 8, 0);
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    p8idct(NULL , temp, dest, line_size, 8, 1, 3);
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}