/* * H.264 IDCT * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at> * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /** * @file h264-idct.c * H.264 IDCT. * @author Michael Niedermayer <michaelni@gmx.at> */ #include "dsputil.h" static always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){ int i; uint8_t *cm = cropTbl + MAX_NEG_CROP; block[0] += 1<<(shift-1); for(i=0; i<4; i++){ const int z0= block[0 + block_stride*i] + block[2 + block_stride*i]; const int z1= block[0 + block_stride*i] - block[2 + block_stride*i]; const int z2= (block[1 + block_stride*i]>>1) - block[3 + block_stride*i]; const int z3= block[1 + block_stride*i] + (block[3 + block_stride*i]>>1); block[0 + block_stride*i]= z0 + z3; block[1 + block_stride*i]= z1 + z2; block[2 + block_stride*i]= z1 - z2; block[3 + block_stride*i]= z0 - z3; } for(i=0; i<4; i++){ const int z0= block[i + block_stride*0] + block[i + block_stride*2]; const int z1= block[i + block_stride*0] - block[i + block_stride*2]; const int z2= (block[i + block_stride*1]>>1) - block[i + block_stride*3]; const int z3= block[i + block_stride*1] + (block[i + block_stride*3]>>1); dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ]; dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ]; dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ]; dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ]; } } void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){ idct_internal(dst, block, stride, 4, 6, 1); } void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){ idct_internal(dst, block, stride, 8, 3, 1); } void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){ idct_internal(dst, block, stride, 8, 3, 0); }