macroblock.c 32 KB
Newer Older
Laurent Aimar's avatar
Laurent Aimar committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
/*****************************************************************************
 * macroblock.c: h264 encoder library
 *****************************************************************************
 * Copyright (C) 2003 Laurent Aimar
 * $Id: macroblock.c,v 1.1 2004/06/03 19:27:08 fenrir Exp $
 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

28
#include "common/common.h"
Laurent Aimar's avatar
Laurent Aimar committed
29 30 31 32 33 34 35 36 37 38 39 40 41
#include "macroblock.h"


static const uint8_t block_idx_x[16] =
{
    0, 1, 0, 1, 2, 3, 2, 3, 0, 1, 0, 1, 2, 3, 2, 3
};
static const uint8_t block_idx_y[16] =
{
    0, 0, 1, 1, 0, 0, 1, 1, 2, 2, 3, 3, 2, 2, 3, 3
};
static const uint8_t block_idx_xy[4][4] =
{
42 43 44 45
    { 0, 2, 8,  10 },
    { 1, 3, 9,  11 },
    { 4, 6, 12, 14 },
    { 5, 7, 13, 15 }
Laurent Aimar's avatar
Laurent Aimar committed
46 47 48 49
};

static const int quant_mf[6][4][4] =
{
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120
    { { 13107, 8066, 13107, 8066 }, { 8066, 5243, 8066, 5243 },
      { 13107, 8066, 13107, 8066 }, { 8066, 5243, 8066, 5243 } },
    { { 11916, 7490, 11916, 7490 }, { 7490, 4660, 7490, 4660 },
      { 11916, 7490, 11916, 7490 }, { 7490, 4660, 7490, 4660 } },
    { { 10082, 6554, 10082, 6554 }, { 6554, 4194, 6554, 4194 },
      { 10082, 6554, 10082, 6554 }, { 6554, 4194, 6554, 4194 } },
    { {  9362, 5825,  9362, 5825 }, { 5825, 3647, 5825, 3647 },
      {  9362, 5825,  9362, 5825 }, { 5825, 3647, 5825, 3647 } },
    { {  8192, 5243,  8192, 5243 }, { 5243, 3355, 5243, 3355 },
      {  8192, 5243,  8192, 5243 }, { 5243, 3355, 5243, 3355 } },
    { {  7282, 4559,  7282, 4559 }, { 4559, 2893, 4559, 2893 },
      {  7282, 4559,  7282, 4559 }, { 4559, 2893, 4559, 2893 } }
};

const int quant8_mf[6][8][8] =
{
  {
    { 13107, 12222, 16777, 12222, 13107, 12222, 16777, 12222 },
    { 12222, 11428, 15481, 11428, 12222, 11428, 15481, 11428 },
    { 16777, 15481, 20972, 15481, 16777, 15481, 20972, 15481 },
    { 12222, 11428, 15481, 11428, 12222, 11428, 15481, 11428 },
    { 13107, 12222, 16777, 12222, 13107, 12222, 16777, 12222 },
    { 12222, 11428, 15481, 11428, 12222, 11428, 15481, 11428 },
    { 16777, 15481, 20972, 15481, 16777, 15481, 20972, 15481 },
    { 12222, 11428, 15481, 11428, 12222, 11428, 15481, 11428 }
  }, {
    { 11916, 11058, 14980, 11058, 11916, 11058, 14980, 11058 },
    { 11058, 10826, 14290, 10826, 11058, 10826, 14290, 10826 },
    { 14980, 14290, 19174, 14290, 14980, 14290, 19174, 14290 },
    { 11058, 10826, 14290, 10826, 11058, 10826, 14290, 10826 },
    { 11916, 11058, 14980, 11058, 11916, 11058, 14980, 11058 },
    { 11058, 10826, 14290, 10826, 11058, 10826, 14290, 10826 },
    { 14980, 14290, 19174, 14290, 14980, 14290, 19174, 14290 },
    { 11058, 10826, 14290, 10826, 11058, 10826, 14290, 10826 }
  }, {
    { 10082,  9675, 12710,  9675, 10082,  9675, 12710,  9675 },
    {  9675,  8943, 11985,  8943,  9675,  8943, 11985,  8943 },
    { 12710, 11985, 15978, 11985, 12710, 11985, 15978, 11985 },
    {  9675,  8943, 11985,  8943,  9675,  8943, 11985,  8943 },
    { 10082,  9675, 12710,  9675, 10082,  9675, 12710,  9675 },
    {  9675,  8943, 11985,  8943,  9675,  8943, 11985,  8943 },
    { 12710, 11985, 15978, 11985, 12710, 11985, 15978, 11985 },
    {  9675,  8943, 11985,  8943,  9675,  8943, 11985,  8943 }
  }, {
    {  9362,  8931, 11984,  8931,  9362,  8931, 11984,  8931 },
    {  8931,  8228, 11259,  8228,  8931,  8228, 11259,  8228 },
    { 11984, 11259, 14913, 11259, 11984, 11259, 14913, 11259 },
    {  8931,  8228, 11259,  8228,  8931,  8228, 11259,  8228 },
    {  9362,  8931, 11984,  8931,  9362,  8931, 11984,  8931 },
    {  8931,  8228, 11259,  8228,  8931,  8228, 11259,  8228 },
    { 11984, 11259, 14913, 11259, 11984, 11259, 14913, 11259 },
    {  8931,  8228, 11259,  8228,  8931,  8228, 11259,  8228 }
  }, {
    {  8192,  7740, 10486,  7740,  8192,  7740, 10486,  7740 },
    {  7740,  7346,  9777,  7346,  7740,  7346,  9777,  7346 },
    { 10486,  9777, 13159,  9777, 10486,  9777, 13159,  9777 },
    {  7740,  7346,  9777,  7346,  7740,  7346,  9777,  7346 },
    {  8192,  7740, 10486,  7740,  8192,  7740, 10486,  7740 },
    {  7740,  7346,  9777,  7346,  7740,  7346,  9777,  7346 },
    { 10486,  9777, 13159,  9777, 10486,  9777, 13159,  9777 },
    {  7740,  7346,  9777,  7346,  7740,  7346,  9777,  7346 }
  }, {
    {  7282,  6830,  9118,  6830,  7282,  6830,  9118,  6830 },
    {  6830,  6428,  8640,  6428,  6830,  6428,  8640,  6428 },
    {  9118,  8640, 11570,  8640,  9118,  8640, 11570,  8640 },
    {  6830,  6428,  8640,  6428,  6830,  6428,  8640,  6428 },
    {  7282,  6830,  9118,  6830,  7282,  6830,  9118,  6830 },
    {  6830,  6428,  8640,  6428,  6830,  6428,  8640,  6428 },
    {  9118,  8640, 11570,  8640,  9118,  8640, 11570,  8640 },
    {  6830,  6428,  8640,  6428,  6830,  6428,  8640,  6428 }
  }
Laurent Aimar's avatar
Laurent Aimar committed
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138
};

static const int i_chroma_qp_table[52] =
{
     0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
    10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
    20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
    29, 30, 31, 32, 32, 33, 34, 34, 35, 35,
    36, 36, 37, 37, 37, 38, 38, 38, 39, 39,
    39, 39
};

/****************************************************************************
 * Scan and Quant functions
 ****************************************************************************/
//static const int scan_zigzag_x[16]={0, 1, 0, 0, 1, 2, 3, 2, 1, 0, 1, 2, 3, 3, 2, 3};
//static const int scan_zigzag_y[16]={0, 0, 1, 2, 1, 0, 0, 1, 2, 3, 3, 2, 1, 2, 3, 3};

139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158
#define ZIG(i,y,x) level[i] = dct[y][x];
static inline void scan_zigzag_8x8full( int level[64], int16_t dct[8][8] )
{
    ZIG( 0,0,0) ZIG( 1,0,1) ZIG( 2,1,0) ZIG( 3,2,0)
    ZIG( 4,1,1) ZIG( 5,0,2) ZIG( 6,0,3) ZIG( 7,1,2)
    ZIG( 8,2,1) ZIG( 9,3,0) ZIG(10,4,0) ZIG(11,3,1)
    ZIG(12,2,2) ZIG(13,1,3) ZIG(14,0,4) ZIG(15,0,5)
    ZIG(16,1,4) ZIG(17,2,3) ZIG(18,3,2) ZIG(19,4,1)
    ZIG(20,5,0) ZIG(21,6,0) ZIG(22,5,1) ZIG(23,4,2)
    ZIG(24,3,3) ZIG(25,2,4) ZIG(26,1,5) ZIG(27,0,6)
    ZIG(28,0,7) ZIG(29,1,6) ZIG(30,2,5) ZIG(31,3,4)
    ZIG(32,4,3) ZIG(33,5,2) ZIG(34,6,1) ZIG(35,7,0)
    ZIG(36,7,1) ZIG(37,6,2) ZIG(38,5,3) ZIG(39,4,4)
    ZIG(40,3,5) ZIG(41,2,6) ZIG(42,1,7) ZIG(43,2,7)
    ZIG(44,3,6) ZIG(45,4,5) ZIG(46,5,4) ZIG(47,6,3)
    ZIG(48,7,2) ZIG(49,7,3) ZIG(50,6,4) ZIG(51,5,5)
    ZIG(52,4,6) ZIG(53,3,7) ZIG(54,4,7) ZIG(55,5,6)
    ZIG(56,6,5) ZIG(57,7,4) ZIG(58,7,5) ZIG(59,6,6)
    ZIG(60,5,7) ZIG(61,6,7) ZIG(62,7,6) ZIG(63,7,7)
}
Laurent Aimar's avatar
Laurent Aimar committed
159 160
static inline void scan_zigzag_4x4full( int level[16], int16_t dct[4][4] )
{
161 162 163 164
    ZIG( 0,0,0) ZIG( 1,0,1) ZIG( 2,1,0) ZIG( 3,2,0)
    ZIG( 4,1,1) ZIG( 5,0,2) ZIG( 6,0,3) ZIG( 7,1,2)
    ZIG( 8,2,1) ZIG( 9,3,0) ZIG(10,3,1) ZIG(11,2,2)
    ZIG(12,1,3) ZIG(13,2,3) ZIG(14,3,2) ZIG(15,3,3)
Laurent Aimar's avatar
Laurent Aimar committed
165 166 167
}
static inline void scan_zigzag_4x4( int level[15], int16_t dct[4][4] )
{
168 169 170 171
                ZIG( 0,0,1) ZIG( 1,1,0) ZIG( 2,2,0)
    ZIG( 3,1,1) ZIG( 4,0,2) ZIG( 5,0,3) ZIG( 6,1,2)
    ZIG( 7,2,1) ZIG( 8,3,0) ZIG( 9,3,1) ZIG(10,2,2)
    ZIG(11,1,3) ZIG(12,2,3) ZIG(13,3,2) ZIG(14,3,3)
Laurent Aimar's avatar
Laurent Aimar committed
172 173 174
}
static inline void scan_zigzag_2x2_dc( int level[4], int16_t dct[2][2] )
{
175 176 177 178
    ZIG(0,0,0)
    ZIG(1,0,1)
    ZIG(2,1,0)
    ZIG(3,1,1)
Laurent Aimar's avatar
Laurent Aimar committed
179
}
180
#undef ZIG
Laurent Aimar's avatar
Laurent Aimar committed
181

182 183 184 185 186
static void quant_8x8( int16_t dct[8][8], int i_qscale, int b_intra )
{
    const int i_qbits = 16 + i_qscale / 6;
    const int i_mf = i_qscale % 6;
    const int f = ( 1 << i_qbits ) / ( b_intra ? 3 : 6 );
Laurent Aimar's avatar
Laurent Aimar committed
187

188 189 190 191 192 193 194 195 196 197 198 199
    int x,y;
    for( y = 0; y < 8; y++ )
    {
        for( x = 0; x < 8; x++ )
        {
            if( dct[y][x] > 0 )
                dct[y][x] = ( f + dct[y][x] * quant8_mf[i_mf][y][x] ) >> i_qbits;
            else
                dct[y][x] = - ( ( f - dct[y][x] * quant8_mf[i_mf][y][x] ) >> i_qbits );
        }
    }
}
Laurent Aimar's avatar
Laurent Aimar committed
200 201 202 203 204 205 206 207 208 209 210 211
static void quant_4x4( int16_t dct[4][4], int i_qscale, int b_intra )
{
    const int i_qbits = 15 + i_qscale / 6;
    const int i_mf = i_qscale % 6;
    const int f = ( 1 << i_qbits ) / ( b_intra ? 3 : 6 );

    int x,y;
    for( y = 0; y < 4; y++ )
    {
        for( x = 0; x < 4; x++ )
        {
            if( dct[y][x] > 0 )
212
                dct[y][x] = ( f + dct[y][x] * quant_mf[i_mf][y][x] ) >> i_qbits;
Laurent Aimar's avatar
Laurent Aimar committed
213
            else
214
                dct[y][x] = - ( ( f - dct[y][x] * quant_mf[i_mf][y][x] ) >> i_qbits );
Laurent Aimar's avatar
Laurent Aimar committed
215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365
        }
    }
}
static void quant_4x4_dc( int16_t dct[4][4], int i_qscale )
{
    const int i_qbits = 15 + i_qscale / 6;
    const int f2 = ( 2 << i_qbits ) / 3;
    const int i_qmf = quant_mf[i_qscale%6][0][0];
    int x,y;

    for( y = 0; y < 4; y++ )
    {
        for( x = 0; x < 4; x++ )
        {
            if( dct[y][x] > 0 )
                dct[y][x] =( f2 + dct[y][x]  * i_qmf) >> ( 1 + i_qbits );
            else
                dct[y][x] = - ( ( f2 - dct[y][x]  * i_qmf ) >> (1 + i_qbits ) );
        }
    }
}
static void quant_2x2_dc( int16_t dct[2][2], int i_qscale, int b_intra )
{
    int const i_qbits = 15 + i_qscale / 6;
    const int f2 = ( 2 << i_qbits ) / ( b_intra ? 3 : 6 );
    const int i_qmf = quant_mf[i_qscale%6][0][0];

    int x,y;
    for( y = 0; y < 2; y++ )
    {
        for( x = 0; x < 2; x++ )
        {
            if( dct[y][x] > 0 )
                dct[y][x] =( f2 + dct[y][x]  * i_qmf) >> ( 1 + i_qbits );
            else
                dct[y][x] = - ( ( f2 - dct[y][x]  * i_qmf ) >> (1 + i_qbits ) );
        }
    }
}
#if 0
/* From a JVT doc */
static const int f_deadzone_intra[4][4][2] = /* [num][den] */
{
    { {1,2}, {3,7}, {2,5}, {1,3} },
    { {3,7}, {2,5}, {1,3}, {1,4} },
    { {2,5}, {1,3}, {1,4}, {1,5} },
    { {1,3}, {1,4}, {1,5}, {1,5} }
};
static const int f_deadzone_inter[4][4][2] = /* [num][den] */
{
    { {1,3}, {2,7}, {4,15},{2,9} },
    { {2,7}, {4,15},{2,9}, {1,6} },
    { {4,15},{2,9}, {1,6}, {1,7} },
    { {2,9}, {1,6}, {1,7}, {2,15} }
};


static void quant_4x4( int16_t dct[4][4], int i_qscale, int b_intra )
{
    const int(*f_deadzone)[4][4][2] = b_intra ? &f_deadzone_intra : &f_deadzone_inter;
    const int i_qbits = 15 + i_qscale / 6;
    const int i_mf = i_qscale % 6;

    int x,y;
    for( y = 0; y < 4; y++ )
    {
        for( x = 0; x < 4; x++ )
        {
#if 0
            const int f = b_intra ?
                          (f_deadzone_intra[y][x][0] * ( 1 << i_qbits ) / f_deadzone_intra[y][x][1])
                          :
                          (f_deadzone_inter[y][x][0] * ( 1 << i_qbits ) / f_deadzone_inter[y][x][1]);
#else
            const int f = (*f_deadzone)[y][x][0] * ( 1 << i_qbits ) / (*f_deadzone)[y][x][1];
#endif

            if( dct[y][x] > 0 )
            {
                dct[y][x] =( f + dct[y][x]  * quant_mf[i_mf][y][x] ) >> i_qbits;
            }
            else
            {
                dct[y][x] = - ( ( f - dct[y][x]  * quant_mf[i_mf][y][x] ) >> i_qbits );
            }
        }
    }
}

static void quant_4x4_dc( int16_t dct[4][4], int i_qscale )
{
    const int i_qbits = 15 + i_qscale / 6;
    const int i_qmf = quant_mf[i_qscale%6][0][0];
    const int f2 = f_deadzone_intra[0][0][0] * ( 2 << i_qbits ) / f_deadzone_intra[0][0][1];
    int x,y;

    for( y = 0; y < 4; y++ )
    {
        for( x = 0; x < 4; x++ )
        {

            if( dct[y][x] > 0 )
            {
                dct[y][x] =( f2 + dct[y][x]  * i_qmf) >> ( 1 + i_qbits );
            }
            else
            {
                dct[y][x] = - ( ( f2 - dct[y][x]  * i_qmf ) >> (1 + i_qbits ) );
            }
        }
    }
}

static void quant_2x2_dc( int16_t dct[2][2], int i_qscale, int b_intra )
{
    int const i_qbits = 15 + i_qscale / 6;
    const int i_qmf = quant_mf[i_qscale%6][0][0];
    const int f2 = b_intra ?
                   (f_deadzone_intra[0][0][0] * ( 2 << i_qbits ) / f_deadzone_intra[0][0][1])
                   :
                   (f_deadzone_inter[0][0][0] * ( 2 << i_qbits ) / f_deadzone_inter[0][0][1]);
    int x,y;
    for( y = 0; y < 2; y++ )
    {
        for( x = 0; x < 2; x++ )
        {
            if( dct[y][x] > 0 )
            {
                dct[y][x] =( f2 + dct[y][x]  * i_qmf) >> ( 1 + i_qbits );
            }
            else
            {
                dct[y][x] = - ( ( f2 - dct[y][x]  * i_qmf ) >> (1 + i_qbits ) );
            }
        }
    }
}


#endif

/* (ref: JVT-B118)
 * x264_mb_decimate_score: given dct coeffs it returns a score to see if we could empty this dct coeffs
 * to 0 (low score means set it to null)
 * Used in inter macroblock (luma and chroma)
 *  luma: for a 8x8 block: if score < 4 -> null
 *        for the complete mb: if score < 6 -> null
 *  chroma: for the complete mb: if score < 7 -> null
 */
static int x264_mb_decimate_score( int *dct, int i_max )
{
366 367 368 369 370 371 372 373 374
    static const int i_ds_table4[16] = {
        3,2,2,1,1,1,0,0,0,0,0,0,0,0,0,0 };
    static const int i_ds_table8[64] = {
        3,3,3,3,2,2,2,2,2,2,2,2,1,1,1,1,
        1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 };

    const int *ds_table = (i_max == 64) ? i_ds_table8 : i_ds_table4;
Laurent Aimar's avatar
Laurent Aimar committed
375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393
    int i_score = 0;
    int idx = i_max - 1;

    while( idx >= 0 && dct[idx] == 0 )
        idx--;

    while( idx >= 0 )
    {
        int i_run;

        if( abs( dct[idx--] ) > 1 )
            return 9;

        i_run = 0;
        while( idx >= 0 && dct[idx] == 0 )
        {
            idx--;
            i_run++;
        }
394
        i_score += ds_table[i_run];
Laurent Aimar's avatar
Laurent Aimar committed
395 396 397 398 399 400 401 402
    }

    return i_score;
}

void x264_mb_encode_i4x4( x264_t *h, int idx, int i_qscale )
{
    const int i_stride = h->mb.pic.i_stride[0];
403 404 405
    const int i_offset = 4 * block_idx_x[idx] + 4 * block_idx_y[idx] * i_stride;
    uint8_t *p_src = &h->mb.pic.p_fenc[0][i_offset];
    uint8_t *p_dst = &h->mb.pic.p_fdec[0][i_offset];
Laurent Aimar's avatar
Laurent Aimar committed
406 407 408 409 410 411 412 413 414 415 416
    int16_t dct4x4[4][4];

    h->dctf.sub4x4_dct( dct4x4, p_src, i_stride, p_dst, i_stride );
    quant_4x4( dct4x4, i_qscale, 1 );
    scan_zigzag_4x4full( h->dct.block[idx].luma4x4, dct4x4 );
    x264_mb_dequant_4x4( dct4x4, i_qscale );

    /* output samples to fdec */
    h->dctf.add4x4_idct( p_dst, i_stride, dct4x4 );
}

417 418 419 420 421 422 423 424 425 426 427 428 429 430 431
void x264_mb_encode_i8x8( x264_t *h, int idx, int i_qscale )
{
    const int i_stride = h->mb.pic.i_stride[0];
    const int i_offset = 8 * (idx&1) + 8 * (idx>>1) * i_stride;
    uint8_t *p_src = &h->mb.pic.p_fenc[0][i_offset];
    uint8_t *p_dst = &h->mb.pic.p_fdec[0][i_offset];
    int16_t dct8x8[8][8];

    h->dctf.sub8x8_dct8( dct8x8, p_src, i_stride, p_dst, i_stride );
    quant_8x8( dct8x8, i_qscale, 1 );
    scan_zigzag_8x8full( h->dct.luma8x8[idx], dct8x8 );
    x264_mb_dequant_8x8( dct8x8, i_qscale );
    h->dctf.add8x8_idct8( p_dst, i_stride, dct8x8 );
}

Laurent Aimar's avatar
Laurent Aimar committed
432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471
static void x264_mb_encode_i16x16( x264_t *h, int i_qscale )
{
    const int i_stride = h->mb.pic.i_stride[0];
    uint8_t  *p_src = h->mb.pic.p_fenc[0];
    uint8_t  *p_dst = h->mb.pic.p_fdec[0];

    int16_t dct4x4[16+1][4][4];

    int i;

    h->dctf.sub16x16_dct( &dct4x4[1], p_src, i_stride, p_dst, i_stride );
    for( i = 0; i < 16; i++ )
    {
        /* copy dc coeff */
        dct4x4[0][block_idx_y[i]][block_idx_x[i]] = dct4x4[1+i][0][0];

        /* quant/scan/dequant */
        quant_4x4( dct4x4[1+i], i_qscale, 1 );
        scan_zigzag_4x4( h->dct.block[i].residual_ac, dct4x4[1+i] );
        x264_mb_dequant_4x4( dct4x4[1+i], i_qscale );
    }

    h->dctf.dct4x4dc( dct4x4[0] );
    quant_4x4_dc( dct4x4[0], i_qscale );
    scan_zigzag_4x4full( h->dct.luma16x16_dc, dct4x4[0] );

    /* output samples to fdec */
    h->dctf.idct4x4dc( dct4x4[0] );
    x264_mb_dequant_4x4_dc( dct4x4[0], i_qscale );  /* XXX not inversed */

    /* calculate dct coeffs */
    for( i = 0; i < 16; i++ )
    {
        /* copy dc coeff */
        dct4x4[1+i][0][0] = dct4x4[0][block_idx_y[i]][block_idx_x[i]];
    }
    /* put pixels to fdec */
    h->dctf.add16x16_idct( p_dst, i_stride, &dct4x4[1] );
}

472
static void x264_mb_encode_8x8_chroma( x264_t *h, int b_inter, int i_qscale )
Laurent Aimar's avatar
Laurent Aimar committed
473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540
{
    int i, ch;

    for( ch = 0; ch < 2; ch++ )
    {
        const int i_stride = h->mb.pic.i_stride[1+ch];
        uint8_t  *p_src = h->mb.pic.p_fenc[1+ch];
        uint8_t  *p_dst = h->mb.pic.p_fdec[1+ch];
        int i_decimate_score = 0;

        int16_t dct2x2[2][2];
        int16_t dct4x4[4][4][4];

        h->dctf.sub8x8_dct( dct4x4, p_src, i_stride, p_dst, i_stride );
        /* calculate dct coeffs */
        for( i = 0; i < 4; i++ )
        {
            /* copy dc coeff */
            dct2x2[block_idx_y[i]][block_idx_x[i]] = dct4x4[i][0][0];

            quant_4x4( dct4x4[i], i_qscale, b_inter ? 0 : 1 );
            scan_zigzag_4x4( h->dct.block[16+i+ch*4].residual_ac, dct4x4[i] );
            x264_mb_dequant_4x4( dct4x4[i], i_qscale );

            if( b_inter )
            {
                i_decimate_score += x264_mb_decimate_score( h->dct.block[16+i+ch*4].residual_ac, 15 );
            }
        }

        h->dctf.dct2x2dc( dct2x2 );
        quant_2x2_dc( dct2x2, i_qscale, b_inter ? 0 : 1 );
        scan_zigzag_2x2_dc( h->dct.chroma_dc[ch], dct2x2 );

        /* output samples to fdec */
        h->dctf.idct2x2dc( dct2x2 );
        x264_mb_dequant_2x2_dc( dct2x2, i_qscale );  /* XXX not inversed */

        if( b_inter && i_decimate_score < 7 )
        {
            /* Near null chroma 8x8 block so make it null (bits saving) */
            for( i = 0; i < 4; i++ )
            {
                int x, y;
                for( x = 0; x < 15; x++ )
                {
                    h->dct.block[16+i+ch*4].residual_ac[x] = 0;
                }
                for( x = 0; x < 4; x++ )
                {
                    for( y = 0; y < 4; y++ )
                    {
                        dct4x4[i][x][y] = 0;
                    }
                }
            }
        }

        /* calculate dct coeffs */
        for( i = 0; i < 4; i++ )
        {
            /* copy dc coeff */
            dct4x4[i][0][0] = dct2x2[block_idx_y[i]][block_idx_x[i]];
        }
        h->dctf.add8x8_idct( p_dst, i_stride, dct4x4 );
    }
}

541 542 543 544 545 546 547 548 549 550 551 552 553 554 555
static void x264_macroblock_encode_skip( x264_t *h )
{
    int i;
    h->mb.i_cbp_luma = 0x00;
    h->mb.i_cbp_chroma = 0x00;

    for( i = 0; i < 16+8; i++ )
    {
        h->mb.cache.non_zero_count[x264_scan8[i]] = 0;
    }

    /* store cbp */
    h->mb.cbp[h->mb.i_mb_xy] = 0;
}

Laurent Aimar's avatar
Laurent Aimar committed
556 557 558 559 560 561
/*****************************************************************************
 * x264_macroblock_encode_pskip:
 *  Encode an already marked skip block
 *****************************************************************************/
void x264_macroblock_encode_pskip( x264_t *h )
{
562 563 564 565
    const int mvx = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][0],
                                h->mb.mv_min[0], h->mb.mv_max[0] );
    const int mvy = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][1],
                                h->mb.mv_min[1], h->mb.mv_max[1] );
Laurent Aimar's avatar
Laurent Aimar committed
566 567

    /* Motion compensation XXX probably unneeded */
568
    h->mc.mc_luma( h->mb.pic.p_fref[0][0], h->mb.pic.i_stride[0],
Laurent Aimar's avatar
Laurent Aimar committed
569 570 571 572
                    h->mb.pic.p_fdec[0],       h->mb.pic.i_stride[0],
                    mvx, mvy, 16, 16 );

    /* Chroma MC */
573
    h->mc.mc_chroma( h->mb.pic.p_fref[0][0][4], h->mb.pic.i_stride[1],
Laurent Aimar's avatar
Laurent Aimar committed
574 575 576
                      h->mb.pic.p_fdec[1],       h->mb.pic.i_stride[1],
                      mvx, mvy, 8, 8 );

577
    h->mc.mc_chroma( h->mb.pic.p_fref[0][0][5], h->mb.pic.i_stride[2],
Laurent Aimar's avatar
Laurent Aimar committed
578 579 580
                      h->mb.pic.p_fdec[2],       h->mb.pic.i_stride[2],
                      mvx, mvy, 8, 8 );

581
    x264_macroblock_encode_skip( h );
Laurent Aimar's avatar
Laurent Aimar committed
582 583 584 585 586 587 588 589
}

/*****************************************************************************
 * x264_macroblock_encode:
 *****************************************************************************/
void x264_macroblock_encode( x264_t *h )
{
    int i_cbp_dc = 0;
590
    int i_qp = h->mb.i_qp;
Laurent Aimar's avatar
Laurent Aimar committed
591 592 593 594 595 596 597 598
    int i;

    if( h->mb.i_type == P_SKIP )
    {
        /* A bit special */
        x264_macroblock_encode_pskip( h );
        return;
    }
599 600 601 602 603 604 605
    if( h->mb.i_type == B_SKIP )
    {
        /* XXX motion compensation is probably unneeded */
        x264_mb_mc( h );
        x264_macroblock_encode_skip( h );
        return;
    }
Laurent Aimar's avatar
Laurent Aimar committed
606 607 608 609

    if( h->mb.i_type == I_16x16 )
    {
        const int i_mode = h->mb.i_intra16x16_pred_mode;
610
        h->mb.b_transform_8x8 = 0;
Laurent Aimar's avatar
Laurent Aimar committed
611 612 613 614
        /* do the right prediction */
        h->predict_16x16[i_mode]( h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0] );

        /* encode the 16x16 macroblock */
615
        x264_mb_encode_i16x16( h, i_qp );
Laurent Aimar's avatar
Laurent Aimar committed
616 617 618 619

        /* fix the pred mode value */
        h->mb.i_intra16x16_pred_mode = x264_mb_pred_mode16x16_fix[i_mode];
    }
620 621
    else if( h->mb.i_type == I_8x8 )
    {
622
        h->mb.b_transform_8x8 = 1;
623 624 625 626 627 628 629
        for( i = 0; i < 4; i++ )
        {
            const int i_dst = h->mb.pic.i_stride[0];
            uint8_t  *p_dst = &h->mb.pic.p_fdec[0][8 * (i&1) + 8 * (i>>1) * i_dst];
            int      i_mode = h->mb.cache.intra4x4_pred_mode[x264_scan8[4*i]];

            h->predict_8x8[i_mode]( p_dst, i_dst, h->mb.i_neighbour8[i] );
630
            x264_mb_encode_i8x8( h, i, i_qp );
631 632 633
            h->mb.cache.intra4x4_pred_mode[x264_scan8[4*i]] = x264_mb_pred_mode4x4_fix(i_mode);
        }
    }
Laurent Aimar's avatar
Laurent Aimar committed
634 635
    else if( h->mb.i_type == I_4x4 )
    {
636
        h->mb.b_transform_8x8 = 0;
Laurent Aimar's avatar
Laurent Aimar committed
637 638 639 640 641 642 643
        for( i = 0; i < 16; i++ )
        {
            const int i_dst = h->mb.pic.i_stride[0];
            uint8_t  *p_dst = &h->mb.pic.p_fdec[0][4 * block_idx_x[i] + 4 * block_idx_y[i] * i_dst];
            int      i_mode = h->mb.cache.intra4x4_pred_mode[x264_scan8[i]];

            h->predict_4x4[i_mode]( p_dst, i_dst );
644
            x264_mb_encode_i4x4( h, i, i_qp );
645
            h->mb.cache.intra4x4_pred_mode[x264_scan8[i]] = x264_mb_pred_mode4x4_fix(i_mode);
Laurent Aimar's avatar
Laurent Aimar committed
646 647 648 649 650 651 652 653 654 655
        }
    }
    else    /* Inter MB */
    {
        int i8x8, i4x4, idx;
        int i_decimate_mb = 0;

        /* Motion compensation */
        x264_mb_mc( h );

656
        if( h->mb.b_transform_8x8 )
Laurent Aimar's avatar
Laurent Aimar committed
657
        {
658 659 660 661
            int16_t dct8x8[4][8][8];
            h->dctf.sub16x16_dct8( dct8x8,
                                   h->mb.pic.p_fenc[0], h->mb.pic.i_stride[0],
                                   h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0] );
Laurent Aimar's avatar
Laurent Aimar committed
662

663
            for( idx = 0; idx < 4; idx++ )
Laurent Aimar's avatar
Laurent Aimar committed
664
            {
665
                int i_decimate_8x8;
Laurent Aimar's avatar
Laurent Aimar committed
666

667
                quant_8x8( dct8x8[idx], i_qp, 0 );
668
                scan_zigzag_8x8full( h->dct.luma8x8[idx], dct8x8[idx] );
669
                x264_mb_dequant_8x8( dct8x8[idx], i_qp );
Laurent Aimar's avatar
Laurent Aimar committed
670

671 672 673 674 675 676 677
                i_decimate_8x8 = x264_mb_decimate_score( h->dct.luma8x8[idx], 64 );
                i_decimate_mb += i_decimate_8x8;
                if( i_decimate_8x8 < 4 )
                {
                    memset( h->dct.luma8x8[idx], 0, sizeof( h->dct.luma8x8[idx] ) );
                    memset( dct8x8[idx], 0, sizeof( dct8x8[idx] ) );
                }
Laurent Aimar's avatar
Laurent Aimar committed
678 679
            }

680 681 682 683 684 685 686 687 688 689 690 691 692
            if( i_decimate_mb < 6 )
                memset( h->dct.luma8x8, 0, sizeof( h->dct.luma8x8 ) );
            else
                h->dctf.add16x16_idct8( h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0], dct8x8 );
        }
        else
        {
            int16_t dct4x4[16][4][4];
            h->dctf.sub16x16_dct( dct4x4,
                                  h->mb.pic.p_fenc[0], h->mb.pic.i_stride[0],
                                  h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0] );

            for( i8x8 = 0; i8x8 < 4; i8x8++ )
Laurent Aimar's avatar
Laurent Aimar committed
693
            {
694 695 696 697
                int i_decimate_8x8;

                /* encode one 4x4 block */
                i_decimate_8x8 = 0;
Laurent Aimar's avatar
Laurent Aimar committed
698 699 700
                for( i4x4 = 0; i4x4 < 4; i4x4++ )
                {
                    idx = i8x8 * 4 + i4x4;
701

702
                    quant_4x4( dct4x4[idx], i_qp, 0 );
703
                    scan_zigzag_4x4full( h->dct.block[idx].luma4x4, dct4x4[idx] );
704
                    x264_mb_dequant_4x4( dct4x4[idx], i_qp );
705 706

                    i_decimate_8x8 += x264_mb_decimate_score( h->dct.block[idx].luma4x4, 16 );
Laurent Aimar's avatar
Laurent Aimar committed
707 708
                }

709 710 711
                /* decimate this 8x8 block */
                i_decimate_mb += i_decimate_8x8;
                if( i_decimate_8x8 < 4 )
Laurent Aimar's avatar
Laurent Aimar committed
712
                {
713 714 715 716 717 718 719 720 721 722
                    for( i4x4 = 0; i4x4 < 4; i4x4++ )
                    {
                        int x, y;
                        idx = i8x8 * 4 + i4x4;
                        for( i = 0; i < 16; i++ )
                            h->dct.block[idx].luma4x4[i] = 0;
                        for( x = 0; x < 4; x++ )
                            for( y = 0; y < 4; y++ )
                                dct4x4[idx][x][y] = 0;
                    }
Laurent Aimar's avatar
Laurent Aimar committed
723 724
                }
            }
725 726 727 728 729 730 731

            if( i_decimate_mb < 6 )
                for( idx = 0; idx < 16; idx++ )
                    for( i = 0; i < 16; i++ )
                        h->dct.block[idx].luma4x4[i] = 0;
            else
                h->dctf.add16x16_idct( h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0], dct4x4 );
Laurent Aimar's avatar
Laurent Aimar committed
732 733 734 735
        }
    }

    /* encode chroma */
736
    i_qp = i_chroma_qp_table[x264_clip3( i_qp + h->pps->i_chroma_qp_index_offset, 0, 51 )];
Laurent Aimar's avatar
Laurent Aimar committed
737 738 739
    if( IS_INTRA( h->mb.i_type ) )
    {
        const int i_mode = h->mb.i_chroma_pred_mode;
740 741
        h->predict_8x8c[i_mode]( h->mb.pic.p_fdec[1], h->mb.pic.i_stride[1] );
        h->predict_8x8c[i_mode]( h->mb.pic.p_fdec[2], h->mb.pic.i_stride[2] );
Laurent Aimar's avatar
Laurent Aimar committed
742 743 744
    }

    /* encode the 8x8 blocks */
745
    x264_mb_encode_8x8_chroma( h, !IS_INTRA( h->mb.i_type ), i_qp );
Laurent Aimar's avatar
Laurent Aimar committed
746 747

    /* Calculate the Luma/Chroma patern and non_zero_count */
748
    h->mb.i_cbp_luma = 0x00;
Laurent Aimar's avatar
Laurent Aimar committed
749 750 751 752 753 754 755 756
    if( h->mb.i_type == I_16x16 )
    {
        for( i = 0; i < 16; i++ )
        {
            const int nz = array_non_zero_count( h->dct.block[i].residual_ac, 15 );
            h->mb.cache.non_zero_count[x264_scan8[i]] = nz;
            if( nz > 0 )
                h->mb.i_cbp_luma = 0x0f;
757 758 759 760 761 762 763 764 765 766 767 768 769 770
        }
    }
    else if( h->mb.b_transform_8x8 )
    {
        /* coded_block_flag is enough for CABAC,
         * but CAVLC needs the full non_zero_count. */
        for( i = 0; i < 4; i++ )
        {
            const int nz = array_non_zero( h->dct.luma8x8[i], 64 );
            int j;
            for( j = 0; j < 4; j++ )
                h->mb.cache.non_zero_count[x264_scan8[4*i+j]] = nz;
            if( nz > 0 )
                h->mb.i_cbp_luma |= 1 << i;
Laurent Aimar's avatar
Laurent Aimar committed
771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816
        }
    }
    else
    {
        for( i = 0; i < 16; i++ )
        {
            const int nz = array_non_zero_count( h->dct.block[i].luma4x4, 16 );
            h->mb.cache.non_zero_count[x264_scan8[i]] = nz;
            if( nz > 0 )
                h->mb.i_cbp_luma |= 1 << (i/4);
        }
    }

    /* Calculate the chroma patern */
    h->mb.i_cbp_chroma = 0x00;
    for( i = 0; i < 8; i++ )
    {
        const int nz = array_non_zero_count( h->dct.block[16+i].residual_ac, 15 );
        h->mb.cache.non_zero_count[x264_scan8[16+i]] = nz;
        if( nz > 0 )
        {
            h->mb.i_cbp_chroma = 0x02;    /* dc+ac (we can't do only ac) */
        }
    }
    if( h->mb.i_cbp_chroma == 0x00 &&
        ( array_non_zero_count( h->dct.chroma_dc[0], 4 ) > 0 || array_non_zero_count( h->dct.chroma_dc[1], 4 ) ) > 0 )
    {
        h->mb.i_cbp_chroma = 0x01;    /* dc only */
    }

    if( h->param.b_cabac )
    {
        if( h->mb.i_type == I_16x16 && array_non_zero_count( h->dct.luma16x16_dc, 16 ) > 0 )
            i_cbp_dc = 0x01;
        else
            i_cbp_dc = 0x00;

        if( array_non_zero_count( h->dct.chroma_dc[0], 4 ) > 0 )
            i_cbp_dc |= 0x02;
        if( array_non_zero_count( h->dct.chroma_dc[1], 4 ) > 0 )
            i_cbp_dc |= 0x04;
    }

    /* store cbp */
    h->mb.cbp[h->mb.i_mb_xy] = (i_cbp_dc << 8) | (h->mb.i_cbp_chroma << 4) | h->mb.i_cbp_luma;

817 818 819 820 821 822 823 824
    if( h->mb.i_type != I_16x16 && h->mb.i_cbp_luma == 0 && h->mb.i_cbp_chroma == 0 )
    {
        /* It won'y change anything at the decoder side but it is needed else the
         * decoder will fail to read the next QP */
        h->mb.qp[h->mb.i_mb_xy] = h->mb.i_last_qp;
    }


Laurent Aimar's avatar
Laurent Aimar committed
825 826 827 828
    /* Check for P_SKIP
     * XXX: in the me perhaps we should take x264_mb_predict_mv_pskip into account
     *      (if multiple mv give same result)*/
    if( h->mb.i_type == P_L0 && h->mb.i_partition == D_16x16 &&
829 830
        h->mb.i_cbp_luma == 0x00 && h->mb.i_cbp_chroma== 0x00 &&
        h->mb.cache.ref[0][x264_scan8[0]] == 0 )
Laurent Aimar's avatar
Laurent Aimar committed
831
    {
832
        int mvp[2];
Laurent Aimar's avatar
Laurent Aimar committed
833

834 835 836 837 838 839
        x264_mb_predict_mv_pskip( h, mvp );
        if( h->mb.cache.mv[0][x264_scan8[0]][0] == mvp[0] &&
            h->mb.cache.mv[0][x264_scan8[0]][1] == mvp[1] )
        {
            h->mb.i_type = P_SKIP;
            h->mb.qp[h->mb.i_mb_xy] = h->mb.i_last_qp;  /* Needed */
840
            /* XXX qp reset may have issues when used in RD instead of the real encode */
Laurent Aimar's avatar
Laurent Aimar committed
841 842
        }
    }
843 844 845 846 847

    /* Check for B_SKIP */
    if( h->mb.i_type == B_DIRECT &&
        h->mb.i_cbp_luma == 0x00 && h->mb.i_cbp_chroma== 0x00 )
    {
848
        h->mb.i_type = B_SKIP;
849 850
        h->mb.qp[h->mb.i_mb_xy] = h->mb.i_last_qp;  /* Needed */
    }
851 852 853

    if( h->mb.i_cbp_luma == 0 && h->mb.i_type != I_8x8 )
        h->mb.b_transform_8x8 = 0;
Laurent Aimar's avatar
Laurent Aimar committed
854 855 856
}

/*****************************************************************************
857 858
 * x264_macroblock_probe_skip:
 *  Check if the current MB could be encoded as a [PB]_SKIP (it supposes you use
Laurent Aimar's avatar
Laurent Aimar committed
859 860
 *  the previous QP
 *****************************************************************************/
861
int x264_macroblock_probe_skip( x264_t *h, int b_bidir )
Laurent Aimar's avatar
Laurent Aimar committed
862 863 864 865 866
{
    DECLARE_ALIGNED( int16_t, dct4x4[16][4][4], 16 );
    DECLARE_ALIGNED( int16_t, dct2x2[2][2], 16 );
    DECLARE_ALIGNED( int,     dctscan[16], 16 );

867
    int i_qp = h->mb.i_qp;
Laurent Aimar's avatar
Laurent Aimar committed
868 869 870 871 872 873
    int mvp[2];
    int ch;

    int i8x8, i4x4;
    int i_decimate_mb;

874 875 876 877
    if( !b_bidir )
    {
        /* Get the MV */
        x264_mb_predict_mv_pskip( h, mvp );
878 879
        mvp[0] = x264_clip3( mvp[0], h->mb.mv_min[0], h->mb.mv_max[0] );
        mvp[1] = x264_clip3( mvp[1], h->mb.mv_min[1], h->mb.mv_max[1] );
Laurent Aimar's avatar
Laurent Aimar committed
880

881
        /* Motion compensation */
882 883
        h->mc.mc_luma( h->mb.pic.p_fref[0][0], h->mb.pic.i_stride[0],
                        h->mb.pic.p_fdec[0],   h->mb.pic.i_stride[0],
884 885
                        mvp[0], mvp[1], 16, 16 );
    }
Laurent Aimar's avatar
Laurent Aimar committed
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919

    /* get luma diff */
    h->dctf.sub16x16_dct( dct4x4, h->mb.pic.p_fenc[0], h->mb.pic.i_stride[0],
                                  h->mb.pic.p_fdec[0], h->mb.pic.i_stride[0] );

    for( i8x8 = 0, i_decimate_mb = 0; i8x8 < 4; i8x8++ )
    {
        /* encode one 4x4 block */
        for( i4x4 = 0; i4x4 < 4; i4x4++ )
        {
            const int idx = i8x8 * 4 + i4x4;

            quant_4x4( dct4x4[idx], i_qp, 0 );
            scan_zigzag_4x4full( dctscan, dct4x4[idx] );

            i_decimate_mb += x264_mb_decimate_score( dctscan, 16 );

            if( i_decimate_mb >= 6 )
            {
                /* not as P_SKIP */
                return 0;
            }
        }
    }

    /* encode chroma */
    i_qp = i_chroma_qp_table[x264_clip3( i_qp + h->pps->i_chroma_qp_index_offset, 0, 51 )];

    for( ch = 0; ch < 2; ch++ )
    {
        const int i_stride = h->mb.pic.i_stride[1+ch];
        uint8_t  *p_src = h->mb.pic.p_fenc[1+ch];
        uint8_t  *p_dst = h->mb.pic.p_fdec[1+ch];

920 921
        if( !b_bidir )
        {
922
            h->mc.mc_chroma( h->mb.pic.p_fref[0][0][4+ch], i_stride,
923 924 925
                              h->mb.pic.p_fdec[1+ch],       i_stride,
                              mvp[0], mvp[1], 8, 8 );
        }
Laurent Aimar's avatar
Laurent Aimar committed
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957

        h->dctf.sub8x8_dct( dct4x4, p_src, i_stride, p_dst, i_stride );

        /* calculate dct DC */
        dct2x2[0][0] = dct4x4[0][0][0];
        dct2x2[0][1] = dct4x4[1][0][0];
        dct2x2[1][0] = dct4x4[2][0][0];
        dct2x2[1][1] = dct4x4[3][0][0];
        h->dctf.dct2x2dc( dct2x2 );
        quant_2x2_dc( dct2x2, i_qp, 0 );
        if( dct2x2[0][0] || dct2x2[0][1] || dct2x2[1][0] || dct2x2[1][1]  )
        {
            /* can't be */
            return 0;
        }

        /* calculate dct coeffs */
        for( i4x4 = 0, i_decimate_mb = 0; i4x4 < 4; i4x4++ )
        {
            quant_4x4( dct4x4[i4x4], i_qp, 0 );
            scan_zigzag_4x4( dctscan, dct4x4[i4x4] );

            i_decimate_mb += x264_mb_decimate_score( dctscan, 15 );
            if( i_decimate_mb >= 7 )
            {
                return 0;
            }
        }
    }

    return 1;
}