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libavcodec/h264idct.c

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00001 /*
00002  * H.264 IDCT
00003  * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include "dsputil.h"
00029 
00030 static av_always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){
00031     int i;
00032     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
00033 
00034     block[0] += 1<<(shift-1);
00035 
00036     for(i=0; i<4; i++){
00037         const int z0=  block[0 + block_stride*i]     +  block[2 + block_stride*i];
00038         const int z1=  block[0 + block_stride*i]     -  block[2 + block_stride*i];
00039         const int z2= (block[1 + block_stride*i]>>1) -  block[3 + block_stride*i];
00040         const int z3=  block[1 + block_stride*i]     + (block[3 + block_stride*i]>>1);
00041 
00042         block[0 + block_stride*i]= z0 + z3;
00043         block[1 + block_stride*i]= z1 + z2;
00044         block[2 + block_stride*i]= z1 - z2;
00045         block[3 + block_stride*i]= z0 - z3;
00046     }
00047 
00048     for(i=0; i<4; i++){
00049         const int z0=  block[i + block_stride*0]     +  block[i + block_stride*2];
00050         const int z1=  block[i + block_stride*0]     -  block[i + block_stride*2];
00051         const int z2= (block[i + block_stride*1]>>1) -  block[i + block_stride*3];
00052         const int z3=  block[i + block_stride*1]     + (block[i + block_stride*3]>>1);
00053 
00054         dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ];
00055         dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ];
00056         dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ];
00057         dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ];
00058     }
00059 }
00060 
00061 void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){
00062     idct_internal(dst, block, stride, 4, 6, 1);
00063 }
00064 
00065 void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
00066     idct_internal(dst, block, stride, 8, 3, 1);
00067 }
00068 
00069 void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){
00070     idct_internal(dst, block, stride, 8, 3, 0);
00071 }
00072 
00073 void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){
00074     int i;
00075     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
00076 
00077     block[0] += 32;
00078 
00079     for( i = 0; i < 8; i++ )
00080     {
00081         const int a0 =  block[0+i*8] + block[4+i*8];
00082         const int a2 =  block[0+i*8] - block[4+i*8];
00083         const int a4 = (block[2+i*8]>>1) - block[6+i*8];
00084         const int a6 = (block[6+i*8]>>1) + block[2+i*8];
00085 
00086         const int b0 = a0 + a6;
00087         const int b2 = a2 + a4;
00088         const int b4 = a2 - a4;
00089         const int b6 = a0 - a6;
00090 
00091         const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
00092         const int a3 =  block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
00093         const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
00094         const int a7 =  block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>1);
00095 
00096         const int b1 = (a7>>2) + a1;
00097         const int b3 =  a3 + (a5>>2);
00098         const int b5 = (a3>>2) - a5;
00099         const int b7 =  a7 - (a1>>2);
00100 
00101         block[0+i*8] = b0 + b7;
00102         block[7+i*8] = b0 - b7;
00103         block[1+i*8] = b2 + b5;
00104         block[6+i*8] = b2 - b5;
00105         block[2+i*8] = b4 + b3;
00106         block[5+i*8] = b4 - b3;
00107         block[3+i*8] = b6 + b1;
00108         block[4+i*8] = b6 - b1;
00109     }
00110     for( i = 0; i < 8; i++ )
00111     {
00112         const int a0 =  block[i+0*8] + block[i+4*8];
00113         const int a2 =  block[i+0*8] - block[i+4*8];
00114         const int a4 = (block[i+2*8]>>1) - block[i+6*8];
00115         const int a6 = (block[i+6*8]>>1) + block[i+2*8];
00116 
00117         const int b0 = a0 + a6;
00118         const int b2 = a2 + a4;
00119         const int b4 = a2 - a4;
00120         const int b6 = a0 - a6;
00121 
00122         const int a1 = -block[i+3*8] + block[i+5*8] - block[i+7*8] - (block[i+7*8]>>1);
00123         const int a3 =  block[i+1*8] + block[i+7*8] - block[i+3*8] - (block[i+3*8]>>1);
00124         const int a5 = -block[i+1*8] + block[i+7*8] + block[i+5*8] + (block[i+5*8]>>1);
00125         const int a7 =  block[i+3*8] + block[i+5*8] + block[i+1*8] + (block[i+1*8]>>1);
00126 
00127         const int b1 = (a7>>2) + a1;
00128         const int b3 =  a3 + (a5>>2);
00129         const int b5 = (a3>>2) - a5;
00130         const int b7 =  a7 - (a1>>2);
00131 
00132         dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ];
00133         dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ];
00134         dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ];
00135         dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ];
00136         dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ];
00137         dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ];
00138         dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ];
00139         dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ];
00140     }
00141 }
00142 
00143 // assumes all AC coefs are 0
00144 void ff_h264_idct_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
00145     int i, j;
00146     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
00147     int dc = (block[0] + 32) >> 6;
00148     for( j = 0; j < 4; j++ )
00149     {
00150         for( i = 0; i < 4; i++ )
00151             dst[i] = cm[ dst[i] + dc ];
00152         dst += stride;
00153     }
00154 }
00155 
00156 void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
00157     int i, j;
00158     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
00159     int dc = (block[0] + 32) >> 6;
00160     for( j = 0; j < 8; j++ )
00161     {
00162         for( i = 0; i < 8; i++ )
00163             dst[i] = cm[ dst[i] + dc ];
00164         dst += stride;
00165     }
00166 }
00167 
00168 //FIXME this table is a duplicate from h264data.h, and will be removed once the tables from, h264 have been split
00169 static const uint8_t scan8[16 + 2*4]={
00170  4+1*8, 5+1*8, 4+2*8, 5+2*8,
00171  6+1*8, 7+1*8, 6+2*8, 7+2*8,
00172  4+3*8, 5+3*8, 4+4*8, 5+4*8,
00173  6+3*8, 7+3*8, 6+4*8, 7+4*8,
00174  1+1*8, 2+1*8,
00175  1+2*8, 2+2*8,
00176  1+4*8, 2+4*8,
00177  1+5*8, 2+5*8,
00178 };
00179 
00180 void ff_h264_idct_add16_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
00181     int i;
00182     for(i=0; i<16; i++){
00183         int nnz = nnzc[ scan8[i] ];
00184         if(nnz){
00185             if(nnz==1 && block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
00186             else                      idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
00187         }
00188     }
00189 }
00190 
00191 void ff_h264_idct_add16intra_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
00192     int i;
00193     for(i=0; i<16; i++){
00194         if(nnzc[ scan8[i] ]) idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
00195         else if(block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
00196     }
00197 }
00198 
00199 void ff_h264_idct8_add4_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
00200     int i;
00201     for(i=0; i<16; i+=4){
00202         int nnz = nnzc[ scan8[i] ];
00203         if(nnz){
00204             if(nnz==1 && block[i*16]) ff_h264_idct8_dc_add_c(dst + block_offset[i], block + i*16, stride);
00205             else                      ff_h264_idct8_add_c   (dst + block_offset[i], block + i*16, stride);
00206         }
00207     }
00208 }
00209 
00210 void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
00211     int i;
00212     for(i=16; i<16+8; i++){
00213         if(nnzc[ scan8[i] ])
00214             ff_h264_idct_add_c   (dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
00215         else if(block[i*16])
00216             ff_h264_idct_dc_add_c(dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
00217     }
00218 }

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