libavcodec/h264idct.c

   1 /*
   2  * H.264 IDCT
   3  * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file libavcodec/h264idct.c
  24  * H.264 IDCT.
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #include "dsputil.h"
  29
  30 static av_always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){
  31     int i;
  32     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
  33
  34     block[0] += 1<<(shift-1);
  35
  36     for(i=0; i<4; i++){
  37         const int z0=  block[0 + block_stride*i]     +  block[2 + block_stride*i];
  38         const int z1=  block[0 + block_stride*i]     -  block[2 + block_stride*i];
  39         const int z2= (block[1 + block_stride*i]>>1) -  block[3 + block_stride*i];
  40         const int z3=  block[1 + block_stride*i]     + (block[3 + block_stride*i]>>1);
  41
  42         block[0 + block_stride*i]= z0 + z3;
  43         block[1 + block_stride*i]= z1 + z2;
  44         block[2 + block_stride*i]= z1 - z2;
  45         block[3 + block_stride*i]= z0 - z3;
  46     }
  47
  48     for(i=0; i<4; i++){
  49         const int z0=  block[i + block_stride*0]     +  block[i + block_stride*2];
  50         const int z1=  block[i + block_stride*0]     -  block[i + block_stride*2];
  51         const int z2= (block[i + block_stride*1]>>1) -  block[i + block_stride*3];
  52         const int z3=  block[i + block_stride*1]     + (block[i + block_stride*3]>>1);
  53
  54         dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ];
  55         dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ];
  56         dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ];
  57         dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ];
  58     }
  59 }
  60
  61 void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){
  62     idct_internal(dst, block, stride, 4, 6, 1);
  63 }
  64
  65 void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
  66     idct_internal(dst, block, stride, 8, 3, 1);
  67 }
  68
  69 void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){
  70     idct_internal(dst, block, stride, 8, 3, 0);
  71 }
  72
  73 void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){
  74     int i;
  75     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
  76
  77     block[0] += 32;
  78
  79     for( i = 0; i < 8; i++ )
  80     {
  81         const int a0 =  block[0+i*8] + block[4+i*8];
  82         const int a2 =  block[0+i*8] - block[4+i*8];
  83         const int a4 = (block[2+i*8]>>1) - block[6+i*8];
  84         const int a6 = (block[6+i*8]>>1) + block[2+i*8];
  85
  86         const int b0 = a0 + a6;
  87         const int b2 = a2 + a4;
  88         const int b4 = a2 - a4;
  89         const int b6 = a0 - a6;
  90
  91         const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
  92         const int a3 =  block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
  93         const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
  94         const int a7 =  block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>1);
  95
  96         const int b1 = (a7>>2) + a1;
  97         const int b3 =  a3 + (a5>>2);
  98         const int b5 = (a3>>2) - a5;
  99         const int b7 =  a7 - (a1>>2);
 100
 101         block[0+i*8] = b0 + b7;
 102         block[7+i*8] = b0 - b7;
 103         block[1+i*8] = b2 + b5;
 104         block[6+i*8] = b2 - b5;
 105         block[2+i*8] = b4 + b3;
 106         block[5+i*8] = b4 - b3;
 107         block[3+i*8] = b6 + b1;
 108         block[4+i*8] = b6 - b1;
 109     }
 110     for( i = 0; i < 8; i++ )
 111     {
 112         const int a0 =  block[i+0*8] + block[i+4*8];
 113         const int a2 =  block[i+0*8] - block[i+4*8];
 114         const int a4 = (block[i+2*8]>>1) - block[i+6*8];
 115         const int a6 = (block[i+6*8]>>1) + block[i+2*8];
 116
 117         const int b0 = a0 + a6;
 118         const int b2 = a2 + a4;
 119         const int b4 = a2 - a4;
 120         const int b6 = a0 - a6;
 121
 122         const int a1 = -block[i+3*8] + block[i+5*8] - block[i+7*8] - (block[i+7*8]>>1);
 123         const int a3 =  block[i+1*8] + block[i+7*8] - block[i+3*8] - (block[i+3*8]>>1);
 124         const int a5 = -block[i+1*8] + block[i+7*8] + block[i+5*8] + (block[i+5*8]>>1);
 125         const int a7 =  block[i+3*8] + block[i+5*8] + block[i+1*8] + (block[i+1*8]>>1);
 126
 127         const int b1 = (a7>>2) + a1;
 128         const int b3 =  a3 + (a5>>2);
 129         const int b5 = (a3>>2) - a5;
 130         const int b7 =  a7 - (a1>>2);
 131
 132         dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ];
 133         dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ];
 134         dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ];
 135         dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ];
 136         dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ];
 137         dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ];
 138         dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ];
 139         dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ];
 140     }
 141 }
 142
 143 // assumes all AC coefs are 0
 144 void ff_h264_idct_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
 145     int i, j;
 146     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
 147     int dc = (block[0] + 32) >> 6;
 148     for( j = 0; j < 4; j++ )
 149     {
 150         for( i = 0; i < 4; i++ )
 151             dst[i] = cm[ dst[i] + dc ];
 152         dst += stride;
 153     }
 154 }
 155
 156 void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
 157     int i, j;
 158     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
 159     int dc = (block[0] + 32) >> 6;
 160     for( j = 0; j < 8; j++ )
 161     {
 162         for( i = 0; i < 8; i++ )
 163             dst[i] = cm[ dst[i] + dc ];
 164         dst += stride;
 165     }
 166 }
 167
 168 //FIXME this table is a duplicate from h264data.h, and will be removed once the tables from, h264 have been split
 169 static const uint8_t scan8[16 + 2*4]={
 170  4+1*8, 5+1*8, 4+2*8, 5+2*8,
 171  6+1*8, 7+1*8, 6+2*8, 7+2*8,
 172  4+3*8, 5+3*8, 4+4*8, 5+4*8,
 173  6+3*8, 7+3*8, 6+4*8, 7+4*8,
 174  1+1*8, 2+1*8,
 175  1+2*8, 2+2*8,
 176  1+4*8, 2+4*8,
 177  1+5*8, 2+5*8,
 178 };
 179
 180 void ff_h264_idct_add16_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
 181     int i;
 182     for(i=0; i<16; i++){
 183         int nnz = nnzc[ scan8[i] ];
 184         if(nnz){
 185             if(nnz==1 && block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
 186             else                      idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
 187         }
 188     }
 189 }
 190
 191 void ff_h264_idct_add16intra_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
 192     int i;
 193     for(i=0; i<16; i++){
 194         if(nnzc[ scan8[i] ]) idct_internal        (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
 195         else if(block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
 196     }
 197 }
 198
 199 void ff_h264_idct8_add4_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
 200     int i;
 201     for(i=0; i<16; i+=4){
 202         int nnz = nnzc[ scan8[i] ];
 203         if(nnz){
 204             if(nnz==1 && block[i*16]) ff_h264_idct8_dc_add_c(dst + block_offset[i], block + i*16, stride);
 205             else                      ff_h264_idct8_add_c   (dst + block_offset[i], block + i*16, stride);
 206         }
 207     }
 208 }
 209
 210 void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
 211     int i;
 212     for(i=16; i<16+8; i++){
 213         if(nnzc[ scan8[i] ])
 214             ff_h264_idct_add_c   (dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
 215         else if(block[i*16])
 216             ff_h264_idct_dc_add_c(dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
 217     }
 218 }