modules/video_chroma/i420_rgb_c.h

   1 /*****************************************************************************
   2  * chroma_common.h: YUV transformation functions
   3  * Provides functions to perform the YUV conversion. The functions provided here
   4  * are a complete and portable C implementation, and may be replaced in certain
   5  * case by optimized functions.
   6  *****************************************************************************
   7  * Copyright (C) 1999, 2000 the VideoLAN team
   8  * $Id$
   9  *
  10  * Authors: Vincent Seguin <seguin@via.ecp.fr>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Constants
  29  *****************************************************************************/
  30
  31 /* Margins and offsets in conversion tables - Margins are used in case a RGB
  32  * RGB conversion would give a value outside the 0-255 range. Offsets have been
  33  * calculated to avoid using the same cache line for 2 tables. conversion tables
  34  * are 2*MARGIN + 256 long and stores pixels.*/
  35 #define RED_MARGIN      178
  36 #define GREEN_MARGIN    135
  37 #define BLUE_MARGIN     224
  38 #define RED_OFFSET      1501                                 /* 1323 to 1935 */
  39 #define GREEN_OFFSET    135                                      /* 0 to 526 */
  40 #define BLUE_OFFSET     818                                   /* 594 to 1298 */
  41 #define RGB_TABLE_SIZE  1935                             /* total table size */
  42
  43 #define GRAY_MARGIN     384
  44 #define GRAY_TABLE_SIZE 1024                             /* total table size */
  45
  46 #define PALETTE_TABLE_SIZE 2176          /* YUV -> 8bpp palette lookup table */
  47
  48 /* macros used for YUV pixel conversions */
  49 #define SHIFT 20
  50 #define U_GREEN_COEF    ((int)(-0.391 * (1<<SHIFT) / 1.164))
  51 #define U_BLUE_COEF     ((int)(2.018 * (1<<SHIFT) / 1.164))
  52 #define V_RED_COEF      ((int)(1.596 * (1<<SHIFT) / 1.164))
  53 #define V_GREEN_COEF    ((int)(-0.813 * (1<<SHIFT) / 1.164))
  54