ffmpeg / libavcodec / h264idct.c @ 5509bffa
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/*
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* H.264 IDCT
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* Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; 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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*/
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/**
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* @file h264-idct.c
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* H.264 IDCT.
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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#include "dsputil.h" |
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static always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){ |
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int i;
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uint8_t *cm = cropTbl + MAX_NEG_CROP; |
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block[0] += 1<<(shift-1); |
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for(i=0; i<4; i++){ |
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const int z0= block[0 + block_stride*i] + block[2 + block_stride*i]; |
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const int z1= block[0 + block_stride*i] - block[2 + block_stride*i]; |
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const int z2= (block[1 + block_stride*i]>>1) - block[3 + block_stride*i]; |
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const int z3= block[1 + block_stride*i] + (block[3 + block_stride*i]>>1); |
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block[0 + block_stride*i]= z0 + z3;
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block[1 + block_stride*i]= z1 + z2;
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block[2 + block_stride*i]= z1 - z2;
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block[3 + block_stride*i]= z0 - z3;
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} |
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for(i=0; i<4; i++){ |
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const int z0= block[i + block_stride*0] + block[i + block_stride*2]; |
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const int z1= block[i + block_stride*0] - block[i + block_stride*2]; |
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const int z2= (block[i + block_stride*1]>>1) - block[i + block_stride*3]; |
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const int z3= block[i + block_stride*1] + (block[i + block_stride*3]>>1); |
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dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ]; |
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dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ]; |
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dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ]; |
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dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ]; |
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} |
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} |
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void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){ |
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idct_internal(dst, block, stride, 4, 6, 1); |
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} |
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void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){ |
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idct_internal(dst, block, stride, 8, 3, 1); |
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} |
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void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){ |
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idct_internal(dst, block, stride, 8, 3, 0); |
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} |
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void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){ |
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int i;
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DCTELEM (*src)[8] = (DCTELEM(*)[8])block; |
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uint8_t *cm = cropTbl + MAX_NEG_CROP; |
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block[0] += 32; |
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for( i = 0; i < 8; i++ ) |
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{ |
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const int a0 = src[i][0] + src[i][4]; |
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const int a2 = src[i][0] - src[i][4]; |
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const int a4 = (src[i][2]>>1) - src[i][6]; |
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const int a6 = (src[i][6]>>1) + src[i][2]; |
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const int b0 = a0 + a6; |
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const int b2 = a2 + a4; |
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const int b4 = a2 - a4; |
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const int b6 = a0 - a6; |
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const int a1 = -src[i][3] + src[i][5] - src[i][7] - (src[i][7]>>1); |
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const int a3 = src[i][1] + src[i][7] - src[i][3] - (src[i][3]>>1); |
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const int a5 = -src[i][1] + src[i][7] + src[i][5] + (src[i][5]>>1); |
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const int a7 = src[i][3] + src[i][5] + src[i][1] + (src[i][1]>>1); |
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const int b1 = (a7>>2) + a1; |
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const int b3 = a3 + (a5>>2); |
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const int b5 = (a3>>2) - a5; |
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const int b7 = a7 - (a1>>2); |
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src[i][0] = b0 + b7;
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src[i][7] = b0 - b7;
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src[i][1] = b2 + b5;
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src[i][6] = b2 - b5;
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src[i][2] = b4 + b3;
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src[i][5] = b4 - b3;
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src[i][3] = b6 + b1;
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src[i][4] = b6 - b1;
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} |
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for( i = 0; i < 8; i++ ) |
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{ |
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const int a0 = src[0][i] + src[4][i]; |
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const int a2 = src[0][i] - src[4][i]; |
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const int a4 = (src[2][i]>>1) - src[6][i]; |
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const int a6 = (src[6][i]>>1) + src[2][i]; |
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const int b0 = a0 + a6; |
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const int b2 = a2 + a4; |
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const int b4 = a2 - a4; |
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const int b6 = a0 - a6; |
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const int a1 = -src[3][i] + src[5][i] - src[7][i] - (src[7][i]>>1); |
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const int a3 = src[1][i] + src[7][i] - src[3][i] - (src[3][i]>>1); |
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const int a5 = -src[1][i] + src[7][i] + src[5][i] + (src[5][i]>>1); |
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const int a7 = src[3][i] + src[5][i] + src[1][i] + (src[1][i]>>1); |
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const int b1 = (a7>>2) + a1; |
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const int b3 = a3 + (a5>>2); |
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const int b5 = (a3>>2) - a5; |
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const int b7 = a7 - (a1>>2); |
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dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ]; |
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dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ]; |
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dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ]; |
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dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ]; |
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dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ]; |
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dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ]; |
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dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ]; |
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dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ]; |
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} |
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} |