git.sesse.net Git - vlc/blob - modules/video_chroma/i420_rgb.c

   1 /*****************************************************************************
   2  * i420_rgb.c : YUV to bitmap RGB conversion module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000, 2001, 2004, 2008 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Sam Hocevar <sam@zoy.org>
   8  *          Damien Fouilleul <damienf@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <math.h>                                            /* exp(), pow() */
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_filter.h>
  38 #include <vlc_cpu.h>
  39
  40 #include "i420_rgb.h"
  41 #if defined (MODULE_NAME_IS_i420_rgb)
  42 #   include "i420_rgb_c.h"
  43     static picture_t *I420_RGB8_Filter         ( filter_t *, picture_t * );
  44 //    static picture_t *I420_RGB16_dither_Filter ( filter_t *, picture_t * );
  45     static picture_t *I420_RGB16_Filter        ( filter_t *, picture_t * );
  46     static picture_t *I420_RGB32_Filter        ( filter_t *, picture_t * );
  47 #else
  48     static picture_t *I420_R5G5B5_Filter       ( filter_t *, picture_t * );
  49     static picture_t *I420_R5G6B5_Filter       ( filter_t *, picture_t * );
  50     static picture_t *I420_A8R8G8B8_Filter     ( filter_t *, picture_t * );
  51     static picture_t *I420_R8G8B8A8_Filter     ( filter_t *, picture_t * );
  52     static picture_t *I420_B8G8R8A8_Filter     ( filter_t *, picture_t * );
  53     static picture_t *I420_A8B8G8R8_Filter     ( filter_t *, picture_t * );
  54 #endif
  55
  56 /*****************************************************************************
  57  * RGB2PIXEL: assemble RGB components to a pixel value, returns a uint32_t
  58  *****************************************************************************/
  59 #define RGB2PIXEL( p_filter, i_r, i_g, i_b )                 \
  60     (((((uint32_t)i_r) >> p_filter->fmt_out.video.i_rrshift) \
  61                        << p_filter->fmt_out.video.i_lrshift) \
  62    | ((((uint32_t)i_g) >> p_filter->fmt_out.video.i_rgshift) \
  63                        << p_filter->fmt_out.video.i_lgshift) \
  64    | ((((uint32_t)i_b) >> p_filter->fmt_out.video.i_rbshift) \
  65                        << p_filter->fmt_out.video.i_lbshift))
  66
  67 /*****************************************************************************
  68  * Local and extern prototypes.
  69  *****************************************************************************/
  70 static int  Activate   ( vlc_object_t * );
  71 static void Deactivate ( vlc_object_t * );
  72
  73 #if defined (MODULE_NAME_IS_i420_rgb)
  74 static void SetGammaTable       ( int *pi_table, double f_gamma );
  75 static void SetYUV              ( filter_t * );
  76 static void Set8bppPalette      ( filter_t *, uint8_t * );
  77 #endif
  78
  79 /*****************************************************************************
  80  * Module descriptor.
  81  *****************************************************************************/
  82 vlc_module_begin ()
  83 #if defined (MODULE_NAME_IS_i420_rgb)
  84     set_description( N_("I420,IYUV,YV12 to "
  85                        "RGB2,RV15,RV16,RV24,RV32 conversions") )
  86     set_capability( "video filter2", 80 )
  87 #elif defined (MODULE_NAME_IS_i420_rgb_mmx)
  88     set_description( N_( "MMX I420,IYUV,YV12 to "
  89                         "RV15,RV16,RV24,RV32 conversions") )
  90     set_capability( "video filter2", 100 )
  91     add_requirement( MMX )
  92 #elif defined (MODULE_NAME_IS_i420_rgb_sse2)
  93     set_description( N_( "SSE2 I420,IYUV,YV12 to "
  94                         "RV15,RV16,RV24,RV32 conversions") )
  95     set_capability( "video filter2", 120 )
  96     add_requirement( SSE2 )
  97 #endif
  98     set_callbacks( Activate, Deactivate )
  99 vlc_module_end ()
 100
 101 /*****************************************************************************
 102  * Activate: allocate a chroma function
 103  *****************************************************************************
 104  * This function allocates and initializes a chroma function
 105  *****************************************************************************/
 106 static int Activate( vlc_object_t *p_this )
 107 {
 108     filter_t *p_filter = (filter_t *)p_this;
 109 #if defined (MODULE_NAME_IS_i420_rgb)
 110     size_t i_tables_size;
 111 #endif
 112
 113     if( p_filter->fmt_out.video.i_width & 1
 114      || p_filter->fmt_out.video.i_height & 1 )
 115     {
 116         return VLC_EGENERIC;
 117     }
 118
 119     switch( p_filter->fmt_in.video.i_chroma )
 120     {
 121         case VLC_CODEC_YV12:
 122         case VLC_CODEC_I420:
 123             switch( p_filter->fmt_out.video.i_chroma )
 124             {
 125 #if defined (MODULE_NAME_IS_i420_rgb)
 126                 case VLC_CODEC_RGB8:
 127                     p_filter->pf_video_filter = I420_RGB8_Filter;
 128                     break;
 129 #endif
 130                 case VLC_CODEC_RGB15:
 131                 case VLC_CODEC_RGB16:
 132 #if ! defined (MODULE_NAME_IS_i420_rgb)
 133                     /* If we don't have support for the bitmasks, bail out */
 134                     if( ( p_filter->fmt_out.video.i_rmask == 0x7c00
 135                        && p_filter->fmt_out.video.i_gmask == 0x03e0
 136                        && p_filter->fmt_out.video.i_bmask == 0x001f ) )
 137                     {
 138                         /* R5G5B6 pixel format */
 139                         msg_Dbg(p_this, "RGB pixel format is R5G5B5");
 140                         p_filter->pf_video_filter = I420_R5G5B5_Filter;
 141                     }
 142                     else if( ( p_filter->fmt_out.video.i_rmask == 0xf800
 143                             && p_filter->fmt_out.video.i_gmask == 0x07e0
 144                             && p_filter->fmt_out.video.i_bmask == 0x001f ) )
 145                     {
 146                         /* R5G6B5 pixel format */
 147                         msg_Dbg(p_this, "RGB pixel format is R5G6B5");
 148                         p_filter->pf_video_filter = I420_R5G6B5_Filter;
 149                     }
 150                     else
 151                         return VLC_EGENERIC;
 152 #else
 153                     // generic C chroma converter */
 154                     p_filter->pf_video_filter = I420_RGB16_Filter;
 155 #endif
 156                     break;
 157
 158 #if 0
 159                 /* Hmmm, is there only X11 using 32bits per pixel for RV24 ? */
 160                 case VLC_CODEC_RGB24:
 161 #endif
 162
 163                 case VLC_CODEC_RGB32:
 164 #if ! defined (MODULE_NAME_IS_i420_rgb)
 165                     /* If we don't have support for the bitmasks, bail out */
 166                     if( p_filter->fmt_out.video.i_rmask == 0x00ff0000
 167                      && p_filter->fmt_out.video.i_gmask == 0x0000ff00
 168                      && p_filter->fmt_out.video.i_bmask == 0x000000ff )
 169                     {
 170                         /* A8R8G8B8 pixel format */
 171                         msg_Dbg(p_this, "RGB pixel format is A8R8G8B8");
 172                         p_filter->pf_video_filter = I420_A8R8G8B8_Filter;
 173                     }
 174                     else if( p_filter->fmt_out.video.i_rmask == 0xff000000
 175                           && p_filter->fmt_out.video.i_gmask == 0x00ff0000
 176                           && p_filter->fmt_out.video.i_bmask == 0x0000ff00 )
 177                     {
 178                         /* R8G8B8A8 pixel format */
 179                         msg_Dbg(p_this, "RGB pixel format is R8G8B8A8");
 180                         p_filter->pf_video_filter = I420_R8G8B8A8_Filter;
 181                     }
 182                     else if( p_filter->fmt_out.video.i_rmask == 0x0000ff00
 183                           && p_filter->fmt_out.video.i_gmask == 0x00ff0000
 184                           && p_filter->fmt_out.video.i_bmask == 0xff000000 )
 185                     {
 186                         /* B8G8R8A8 pixel format */
 187                         msg_Dbg(p_this, "RGB pixel format is B8G8R8A8");
 188                         p_filter->pf_video_filter = I420_B8G8R8A8_Filter;
 189                     }
 190                     else if( p_filter->fmt_out.video.i_rmask == 0x000000ff
 191                           && p_filter->fmt_out.video.i_gmask == 0x0000ff00
 192                           && p_filter->fmt_out.video.i_bmask == 0x00ff0000 )
 193                     {
 194                         /* A8B8G8R8 pixel format */
 195                         msg_Dbg(p_this, "RGB pixel format is A8B8G8R8");
 196                         p_filter->pf_video_filter = I420_A8B8G8R8_Filter;
 197                     }
 198                     else
 199                         return VLC_EGENERIC;
 200 #else
 201                     /* generic C chroma converter */
 202                     p_filter->pf_video_filter = I420_RGB32_Filter;
 203 #endif
 204                     break;
 205
 206                 default:
 207                     return VLC_EGENERIC;
 208             }
 209             break;
 210
 211         default:
 212             return VLC_EGENERIC;
 213     }
 214
 215     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 216     if( p_filter->p_sys == NULL )
 217     {
 218         return VLC_EGENERIC;
 219     }
 220
 221     switch( p_filter->fmt_out.video.i_chroma )
 222     {
 223 #if defined (MODULE_NAME_IS_i420_rgb)
 224         case VLC_CODEC_RGB8:
 225             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH );
 226             break;
 227 #endif
 228
 229         case VLC_CODEC_RGB15:
 230         case VLC_CODEC_RGB16:
 231             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH * 2 );
 232             break;
 233
 234         case VLC_CODEC_RGB24:
 235         case VLC_CODEC_RGB32:
 236             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH * 4 );
 237             break;
 238
 239         default:
 240             p_filter->p_sys->p_buffer = NULL;
 241             break;
 242     }
 243
 244     if( p_filter->p_sys->p_buffer == NULL )
 245     {
 246         free( p_filter->p_sys );
 247         return VLC_EGENERIC;
 248     }
 249
 250     p_filter->p_sys->p_offset = malloc( p_filter->fmt_out.video.i_width
 251                     * ( ( p_filter->fmt_out.video.i_chroma
 252                            == VLC_CODEC_RGB8 ) ? 2 : 1 )
 253                     * sizeof( int ) );
 254     if( p_filter->p_sys->p_offset == NULL )
 255     {
 256         free( p_filter->p_sys->p_buffer );
 257         free( p_filter->p_sys );
 258         return VLC_EGENERIC;
 259     }
 260
 261 #if defined (MODULE_NAME_IS_i420_rgb)
 262     switch( p_filter->fmt_out.video.i_chroma )
 263     {
 264     case VLC_CODEC_RGB8:
 265         i_tables_size = sizeof( uint8_t ) * PALETTE_TABLE_SIZE;
 266         break;
 267     case VLC_CODEC_RGB15:
 268     case VLC_CODEC_RGB16:
 269         i_tables_size = sizeof( uint16_t ) * RGB_TABLE_SIZE;
 270         break;
 271     default: /* RV24, RV32 */
 272         i_tables_size = sizeof( uint32_t ) * RGB_TABLE_SIZE;
 273         break;
 274     }
 275
 276     p_filter->p_sys->p_base = malloc( i_tables_size );
 277     if( p_filter->p_sys->p_base == NULL )
 278     {
 279         free( p_filter->p_sys->p_offset );
 280         free( p_filter->p_sys->p_buffer );
 281         free( p_filter->p_sys );
 282         return -1;
 283     }
 284
 285     SetYUV( p_filter );
 286 #endif
 287
 288     return 0;
 289 }
 290
 291 /*****************************************************************************
 292  * Deactivate: free the chroma function
 293  *****************************************************************************
 294  * This function frees the previously allocated chroma function
 295  *****************************************************************************/
 296 static void Deactivate( vlc_object_t *p_this )
 297 {
 298     filter_t *p_filter = (filter_t *)p_this;
 299
 300 #if defined (MODULE_NAME_IS_i420_rgb)
 301     free( p_filter->p_sys->p_base );
 302 #endif
 303     free( p_filter->p_sys->p_offset );
 304     free( p_filter->p_sys->p_buffer );
 305     free( p_filter->p_sys );
 306 }
 307
 308 #if defined (MODULE_NAME_IS_i420_rgb)
 309 VIDEO_FILTER_WRAPPER( I420_RGB8 )
 310 VIDEO_FILTER_WRAPPER( I420_RGB16 )
 311 //VIDEO_FILTER_WRAPPER( I420_RGB16_dither )
 312 VIDEO_FILTER_WRAPPER( I420_RGB32 )
 313 #else
 314 VIDEO_FILTER_WRAPPER( I420_R5G5B5 )
 315 VIDEO_FILTER_WRAPPER( I420_R5G6B5 )
 316 VIDEO_FILTER_WRAPPER( I420_A8R8G8B8 )
 317 VIDEO_FILTER_WRAPPER( I420_R8G8B8A8 )
 318 VIDEO_FILTER_WRAPPER( I420_B8G8R8A8 )
 319 VIDEO_FILTER_WRAPPER( I420_A8B8G8R8 )
 320 #endif
 321
 322 #if defined (MODULE_NAME_IS_i420_rgb)
 323 /*****************************************************************************
 324  * SetGammaTable: return intensity table transformed by gamma curve.
 325  *****************************************************************************
 326  * pi_table is a table of 256 entries from 0 to 255.
 327  *****************************************************************************/
 328 static void SetGammaTable( int *pi_table, double f_gamma )
 329 {
 330     int i_y;                                               /* base intensity */
 331
 332     /* Use exp(gamma) instead of gamma */
 333     f_gamma = exp( f_gamma );
 334
 335     /* Build gamma table */
 336     for( i_y = 0; i_y < 256; i_y++ )
 337     {
 338         pi_table[ i_y ] = (int)( pow( (double)i_y / 256, f_gamma ) * 256 );
 339     }
 340 }
 341
 342 /*****************************************************************************
 343  * SetYUV: compute tables and set function pointers
 344  *****************************************************************************/
 345 static void SetYUV( filter_t *p_filter )
 346 {
 347     int          pi_gamma[256];                               /* gamma table */
 348     volatile int i_index;                                 /* index in tables */
 349                    /* We use volatile here to work around a strange gcc-3.3.4
 350                     * optimization bug */
 351
 352     /* Build gamma table */
 353     SetGammaTable( pi_gamma, 0 ); //p_filter/*FIXME wasn't used anywhere anyway*/->f_gamma );
 354
 355     /*
 356      * Set pointers and build YUV tables
 357      */
 358
 359     /* Color: build red, green and blue tables */
 360     switch( p_filter->fmt_out.video.i_chroma )
 361     {
 362     case VLC_CODEC_RGB8:
 363         p_filter->p_sys->p_rgb8 = (uint8_t *)p_filter->p_sys->p_base;
 364         Set8bppPalette( p_filter, p_filter->p_sys->p_rgb8 );
 365         break;
 366
 367     case VLC_CODEC_RGB15:
 368     case VLC_CODEC_RGB16:
 369         p_filter->p_sys->p_rgb16 = (uint16_t *)p_filter->p_sys->p_base;
 370         for( i_index = 0; i_index < RED_MARGIN; i_index++ )
 371         {
 372             p_filter->p_sys->p_rgb16[RED_OFFSET - RED_MARGIN + i_index] = RGB2PIXEL( p_filter, pi_gamma[0], 0, 0 );
 373             p_filter->p_sys->p_rgb16[RED_OFFSET + 256 + i_index] =        RGB2PIXEL( p_filter, pi_gamma[255], 0, 0 );
 374         }
 375         for( i_index = 0; i_index < GREEN_MARGIN; i_index++ )
 376         {
 377             p_filter->p_sys->p_rgb16[GREEN_OFFSET - GREEN_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[0], 0 );
 378             p_filter->p_sys->p_rgb16[GREEN_OFFSET + 256 + i_index] =          RGB2PIXEL( p_filter, 0, pi_gamma[255], 0 );
 379         }
 380         for( i_index = 0; i_index < BLUE_MARGIN; i_index++ )
 381         {
 382             p_filter->p_sys->p_rgb16[BLUE_OFFSET - BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[0] );
 383             p_filter->p_sys->p_rgb16[BLUE_OFFSET + BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[255] );
 384         }
 385         for( i_index = 0; i_index < 256; i_index++ )
 386         {
 387             p_filter->p_sys->p_rgb16[RED_OFFSET + i_index] =   RGB2PIXEL( p_filter, pi_gamma[ i_index ], 0, 0 );
 388             p_filter->p_sys->p_rgb16[GREEN_OFFSET + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[ i_index ], 0 );
 389             p_filter->p_sys->p_rgb16[BLUE_OFFSET + i_index] =  RGB2PIXEL( p_filter, 0, 0, pi_gamma[ i_index ] );
 390         }
 391         break;
 392
 393     case VLC_CODEC_RGB24:
 394     case VLC_CODEC_RGB32:
 395         p_filter->p_sys->p_rgb32 = (uint32_t *)p_filter->p_sys->p_base;
 396         for( i_index = 0; i_index < RED_MARGIN; i_index++ )
 397         {
 398             p_filter->p_sys->p_rgb32[RED_OFFSET - RED_MARGIN + i_index] = RGB2PIXEL( p_filter, pi_gamma[0], 0, 0 );
 399             p_filter->p_sys->p_rgb32[RED_OFFSET + 256 + i_index] =        RGB2PIXEL( p_filter, pi_gamma[255], 0, 0 );
 400         }
 401         for( i_index = 0; i_index < GREEN_MARGIN; i_index++ )
 402         {
 403             p_filter->p_sys->p_rgb32[GREEN_OFFSET - GREEN_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[0], 0 );
 404             p_filter->p_sys->p_rgb32[GREEN_OFFSET + 256 + i_index] =          RGB2PIXEL( p_filter, 0, pi_gamma[255], 0 );
 405         }
 406         for( i_index = 0; i_index < BLUE_MARGIN; i_index++ )
 407         {
 408             p_filter->p_sys->p_rgb32[BLUE_OFFSET - BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[0] );
 409             p_filter->p_sys->p_rgb32[BLUE_OFFSET + BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[255] );
 410         }
 411         for( i_index = 0; i_index < 256; i_index++ )
 412         {
 413             p_filter->p_sys->p_rgb32[RED_OFFSET + i_index] =   RGB2PIXEL( p_filter, pi_gamma[ i_index ], 0, 0 );
 414             p_filter->p_sys->p_rgb32[GREEN_OFFSET + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[ i_index ], 0 );
 415             p_filter->p_sys->p_rgb32[BLUE_OFFSET + i_index] =  RGB2PIXEL( p_filter, 0, 0, pi_gamma[ i_index ] );
 416         }
 417         break;
 418     }
 419 }
 420
 421 static void Set8bppPalette( filter_t *p_filter, uint8_t *p_rgb8 )
 422 {
 423     #define CLIP( x ) ( ((x < 0) ? 0 : (x > 255) ? 255 : x) << 8 )
 424
 425     int y,u,v;
 426     int r,g,b;
 427     int i = 0, j = 0;
 428     uint16_t *p_cmap_r = p_filter->p_sys->p_rgb_r;
 429     uint16_t *p_cmap_g = p_filter->p_sys->p_rgb_g;
 430     uint16_t *p_cmap_b = p_filter->p_sys->p_rgb_b;
 431
 432     unsigned char p_lookup[PALETTE_TABLE_SIZE];
 433
 434     /* This loop calculates the intersection of an YUV box and the RGB cube. */
 435     for ( y = 0; y <= 256; y += 16, i += 128 - 81 )
 436     {
 437         for ( u = 0; u <= 256; u += 32 )
 438         {
 439             for ( v = 0; v <= 256; v += 32 )
 440             {
 441                 r = y + ( (V_RED_COEF*(v-128)) >> SHIFT );
 442                 g = y + ( (U_GREEN_COEF*(u-128)
 443                          + V_GREEN_COEF*(v-128)) >> SHIFT );
 444                 b = y + ( (U_BLUE_COEF*(u-128)) >> SHIFT );
 445
 446                 if( r >= 0x00 && g >= 0x00 && b >= 0x00
 447                         && r <= 0xff && g <= 0xff && b <= 0xff )
 448                 {
 449                     /* This one should never happen unless someone
 450                      * fscked up my code */
 451                     if( j == 256 )
 452                     {
 453                         msg_Err( p_filter, "no colors left in palette" );
 454                         break;
 455                     }
 456
 457                     /* Clip the colors */
 458                     p_cmap_r[ j ] = CLIP( r );
 459                     p_cmap_g[ j ] = CLIP( g );
 460                     p_cmap_b[ j ] = CLIP( b );
 461
 462 #if 0
 463             printf("+++Alloc RGB cmap %d (%d, %d, %d)\n", j,
 464                p_cmap_r[ j ] >>8, p_cmap_g[ j ] >>8,
 465                p_cmap_b[ j ] >>8);
 466 #endif
 467
 468                     /* Allocate color */
 469                     p_lookup[ i ] = 1;
 470                     p_rgb8[ i++ ] = j;
 471                     j++;
 472                 }
 473                 else
 474                 {
 475                     p_lookup[ i ] = 0;
 476                     p_rgb8[ i++ ] = 0;
 477                 }
 478             }
 479         }
 480     }
 481
 482     /* The colors have been allocated, we can set the palette */
 483     /* FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME
 484     p_filter->fmt_out.video.pf_setpalette( p_filter, p_cmap_r, p_cmap_g, p_cmap_b );*/
 485
 486 #if 0
 487     /* There will eventually be a way to know which colors
 488      * couldn't be allocated and try to find a replacement */
 489     p_vout->i_white_pixel = 0xff;
 490     p_vout->i_black_pixel = 0x00;
 491     p_vout->i_gray_pixel = 0x44;
 492     p_vout->i_blue_pixel = 0x3b;
 493 #endif
 494
 495     /* This loop allocates colors that got outside the RGB cube */
 496     for ( i = 0, y = 0; y <= 256; y += 16, i += 128 - 81 )
 497     {
 498         for ( u = 0; u <= 256; u += 32 )
 499         {
 500             for ( v = 0; v <= 256; v += 32, i++ )
 501             {
 502                 int u2, v2, dist, mindist = 100000000;
 503
 504                 if( p_lookup[ i ] || y == 0 )
 505                 {
 506                     continue;
 507                 }
 508
 509                 /* Heavy. yeah. */
 510                 for( u2 = 0; u2 <= 256; u2 += 32 )
 511                 {
 512                     for( v2 = 0; v2 <= 256; v2 += 32 )
 513                     {
 514                         j = ((y>>4)<<7) + (u2>>5)*9 + (v2>>5);
 515                         dist = (u-u2)*(u-u2) + (v-v2)*(v-v2);
 516
 517                         /* Find the nearest color */
 518                         if( p_lookup[ j ] && dist < mindist )
 519                         {
 520                             p_rgb8[ i ] = p_rgb8[ j ];
 521                             mindist = dist;
 522                         }
 523
 524                         j -= 128;
 525
 526                         /* Find the nearest color */
 527                         if( p_lookup[ j ] && dist + 128 < mindist )
 528                         {
 529                             p_rgb8[ i ] = p_rgb8[ j ];
 530                             mindist = dist + 128;
 531                         }
 532                     }
 533                 }
 534             }
 535         }
 536     }
 537 }
 538
 539 #endif
 540