plugins/chroma/i420_rgb8.c

   1 /*****************************************************************************
   2  * i420_rgb8.c : YUV to bitmap RGB conversion module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000 VideoLAN
   5  * $Id: i420_rgb8.c,v 1.5 2002/04/02 10:17:08 sam Exp $
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <errno.h>                                                 /* ENOMEM */
  28 #include <string.h>                                            /* strerror() */
  29 #include <stdlib.h>                                      /* malloc(), free() */
  30
  31 #include <videolan/vlc.h>
  32
  33 #include "video.h"
  34 #include "video_output.h"
  35
  36 #include "i420_rgb.h"
  37 #include "i420_rgb_c.h"
  38
  39 static void SetOffset( int, int, int, int, boolean_t *, int *, int * );
  40
  41 /*****************************************************************************
  42  * I420_RGB8: color YUV 4:2:0 to RGB 8 bpp
  43  *****************************************************************************/
  44 void _M( I420_RGB8 )( vout_thread_t *p_vout, picture_t *p_src,
  45                                              picture_t *p_dest )
  46 {
  47     /* We got this one from the old arguments */
  48     u8 *p_pic = (u8*)p_dest->p->p_pixels;
  49     u8 *p_y   = p_src->Y_PIXELS;
  50     u8 *p_u   = p_src->U_PIXELS;
  51     u8 *p_v   = p_src->V_PIXELS;
  52
  53     boolean_t   b_hscale;             /* horizontal scaling type */
  54     int         i_vscale;                 /* vertical scaling type */
  55     int         i_x, i_y;                 /* horizontal and vertical indexes */
  56     int         i_real_y;                                           /* y % 4 */
  57     int         i_right_margin;
  58     int         i_scale_count;                       /* scale modulo counter */
  59     int         i_chroma_width = p_vout->render.i_width / 2; /* chroma width */
  60
  61     /* Lookup table */
  62     u8 *        p_lookup = p_vout->chroma.p_sys->p_base;
  63
  64     /* Offset array pointer */
  65     int *       p_offset_start = p_vout->chroma.p_sys->p_offset;
  66     int *       p_offset;
  67
  68     /* The dithering matrices */
  69     static int dither10[4] = {  0x0,  0x8,  0x2,  0xa };
  70     static int dither11[4] = {  0xc,  0x4,  0xe,  0x6 };
  71     static int dither12[4] = {  0x3,  0xb,  0x1,  0x9 };
  72     static int dither13[4] = {  0xf,  0x7,  0xd,  0x5 };
  73
  74     static int dither20[4] = {  0x0, 0x10,  0x4, 0x14 };
  75     static int dither21[4] = { 0x18,  0x8, 0x1c,  0xc };
  76     static int dither22[4] = {  0x6, 0x16,  0x2, 0x12 };
  77     static int dither23[4] = { 0x1e,  0xe, 0x1a,  0xa };
  78
  79     SetOffset( p_vout->render.i_width, p_vout->render.i_height,
  80                p_vout->output.i_width, p_vout->output.i_height,
  81                &b_hscale, &i_vscale, p_offset_start );
  82
  83     if( p_dest->p->b_margin )
  84     {
  85         i_right_margin = (p_dest->p->i_pitch - p_dest->p->i_visible_bytes);
  86     }
  87     else
  88     {
  89         i_right_margin = 0;
  90     }
  91
  92     /*
  93      * Perform conversion
  94      */
  95     i_scale_count = ( i_vscale == 1 ) ?
  96                     p_vout->output.i_height : p_vout->render.i_height;
  97     for( i_y = 0, i_real_y = 0; i_y < p_vout->render.i_height; i_y++ )
  98     {
  99         /* Do horizontal and vertical scaling */
 100         SCALE_WIDTH_DITHER( 420 );
 101         SCALE_HEIGHT_DITHER( 420 );
 102     }
 103 }
 104
 105 /* Following functions are local */
 106
 107 /*****************************************************************************
 108  * SetOffset: build offset array for conversion functions
 109  *****************************************************************************
 110  * This function will build an offset array used in later conversion functions.
 111  * It will also set horizontal and vertical scaling indicators. The p_offset
 112  * structure has interleaved Y and U/V offsets.
 113  *****************************************************************************/
 114 static void SetOffset( int i_width, int i_height, int i_pic_width,
 115                        int i_pic_height, boolean_t *pb_hscale,
 116                        int *pi_vscale, int *p_offset )
 117 {
 118     int i_x;                                    /* x position in destination */
 119     int i_scale_count;                                     /* modulo counter */
 120
 121     /*
 122      * Prepare horizontal offset array
 123      */
 124     if( i_pic_width - i_width == 0 )
 125     {
 126         /* No horizontal scaling: YUV conversion is done directly to picture */
 127         *pb_hscale = 0;
 128     }
 129     else if( i_pic_width - i_width > 0 )
 130     {
 131         int i_dummy = 0;
 132
 133         /* Prepare scaling array for horizontal extension */
 134         *pb_hscale = 1;
 135         i_scale_count = i_pic_width;
 136         for( i_x = i_width; i_x--; )
 137         {
 138             while( (i_scale_count -= i_width) > 0 )
 139             {
 140                 *p_offset++ = 0;
 141                 *p_offset++ = 0;
 142             }
 143             *p_offset++ = 1;
 144             *p_offset++ = i_dummy;
 145             i_dummy = 1 - i_dummy;
 146             i_scale_count += i_pic_width;
 147         }
 148     }
 149     else /* if( i_pic_width - i_width < 0 ) */
 150     {
 151         int i_remainder = 0;
 152         int i_jump;
 153
 154         /* Prepare scaling array for horizontal reduction */
 155         *pb_hscale = 1;
 156         i_scale_count = i_width;
 157         for( i_x = i_pic_width; i_x--; )
 158         {
 159             i_jump = 1;
 160             while( (i_scale_count -= i_pic_width) > 0 )
 161             {
 162                 i_jump += 1;
 163             }
 164             *p_offset++ = i_jump;
 165             *p_offset++ = ( i_jump += i_remainder ) >> 1;
 166             i_remainder = i_jump & 1;
 167             i_scale_count += i_width;
 168         }
 169     }
 170
 171     /*
 172      * Set vertical scaling indicator
 173      */
 174     if( i_pic_height - i_height == 0 )
 175     {
 176         *pi_vscale = 0;
 177     }
 178     else if( i_pic_height - i_height > 0 )
 179     {
 180         *pi_vscale = 1;
 181     }
 182     else /* if( i_pic_height - i_height < 0 ) */
 183     {
 184         *pi_vscale = -1;
 185     }
 186 }
 187