git.sesse.net Git - ffmpeg/blob - libavcodec/imgconvert.c

   1 /*
   2  * Misc image convertion routines
   3  * Copyright (c) 2001 Gerard Lantau.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include "avcodec.h"
  23
  24 /* XXX: totally non optimized */
  25
  26 static void yuv422_to_yuv420p(UINT8 *lum, UINT8 *cb, UINT8 *cr,
  27                               UINT8 *src, int width, int height)
  28 {
  29     int x, y;
  30     UINT8 *p = src;
  31
  32     for(y=0;y<height;y+=2) {
  33         for(x=0;x<width;x+=2) {
  34             lum[0] = p[0];
  35             cb[0] = p[1];
  36             lum[1] = p[2];
  37             cr[0] = p[3];
  38             p += 4;
  39             lum += 2;
  40             cb++;
  41             cr++;
  42         }
  43         for(x=0;x<width;x+=2) {
  44             lum[0] = p[0];
  45             lum[1] = p[2];
  46             p += 4;
  47             lum += 2;
  48         }
  49     }
  50 }
  51
  52 #define SCALEBITS 8
  53 #define ONE_HALF  (1 << (SCALEBITS - 1))
  54 #define FIX(x)          ((int) ((x) * (1L<<SCALEBITS) + 0.5))
  55
  56 static void rgb24_to_yuv420p(UINT8 *lum, UINT8 *cb, UINT8 *cr,
  57                               UINT8 *src, int width, int height)
  58 {
  59     int wrap, wrap3, x, y;
  60     int r, g, b, r1, g1, b1;
  61     UINT8 *p;
  62
  63     wrap = width;
  64     wrap3 = width * 3;
  65     p = src;
  66     for(y=0;y<height;y+=2) {
  67         for(x=0;x<width;x+=2) {
  68             r = p[0];
  69             g = p[1];
  70             b = p[2];
  71             r1 = r;
  72             g1 = g;
  73             b1 = b;
  74             lum[0] = (FIX(0.29900) * r + FIX(0.58700) * g +
  75                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
  76             r = p[3];
  77             g = p[4];
  78             b = p[5];
  79             r1 += r;
  80             g1 += g;
  81             b1 += b;
  82             lum[1] = (FIX(0.29900) * r + FIX(0.58700) * g +
  83                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
  84             p += wrap3;
  85             lum += wrap;
  86
  87             r = p[0];
  88             g = p[1];
  89             b = p[2];
  90             r1 += r;
  91             g1 += g;
  92             b1 += b;
  93             lum[0] = (FIX(0.29900) * r + FIX(0.58700) * g +
  94                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
  95             r = p[3];
  96             g = p[4];
  97             b = p[5];
  98             r1 += r;
  99             g1 += g;
 100             b1 += b;
 101             lum[1] = (FIX(0.29900) * r + FIX(0.58700) * g +
 102                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 103
 104             cb[0] = ((- FIX(0.16874) * r1 - FIX(0.33126) * g1 +
 105                       FIX(0.50000) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
 106             cr[0] = ((FIX(0.50000) * r1 - FIX(0.41869) * g1 -
 107                      FIX(0.08131) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
 108
 109             cb++;
 110             cr++;
 111             p += -wrap3 + 2 * 3;
 112             lum += -wrap + 2;
 113         }
 114         p += wrap3;
 115         lum += wrap;
 116     }
 117 }
 118
 119 static void bgr24_to_yuv420p(UINT8 *lum, UINT8 *cb, UINT8 *cr,
 120                               UINT8 *src, int width, int height)
 121 {
 122     int wrap, wrap3, x, y;
 123     int r, g, b, r1, g1, b1;
 124     UINT8 *p;
 125
 126     wrap = width;
 127     wrap3 = width * 3;
 128     p = src;
 129     for(y=0;y<height;y+=2) {
 130         for(x=0;x<width;x+=2) {
 131             b = p[0];
 132             g = p[1];
 133             r = p[2];
 134             r1 = r;
 135             g1 = g;
 136             b1 = b;
 137             lum[0] = (FIX(0.29900) * r + FIX(0.58700) * g +
 138                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 139             b = p[3];
 140             g = p[4];
 141             r = p[5];
 142             r1 += r;
 143             g1 += g;
 144             b1 += b;
 145             lum[1] = (FIX(0.29900) * r + FIX(0.58700) * g +
 146                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 147             p += wrap3;
 148             lum += wrap;
 149
 150             b = p[0];
 151             g = p[1];
 152             r = p[2];
 153             r1 += r;
 154             g1 += g;
 155             b1 += b;
 156             lum[0] = (FIX(0.29900) * r + FIX(0.58700) * g +
 157                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 158             b = p[3];
 159             g = p[4];
 160             r = p[5];
 161             r1 += r;
 162             g1 += g;
 163             b1 += b;
 164             lum[1] = (FIX(0.29900) * r + FIX(0.58700) * g +
 165                       FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 166
 167             cb[0] = ((- FIX(0.16874) * r1 - FIX(0.33126) * g1 +
 168                       FIX(0.50000) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
 169             cr[0] = ((FIX(0.50000) * r1 - FIX(0.41869) * g1 -
 170                      FIX(0.08131) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
 171
 172             cb++;
 173             cr++;
 174             p += -wrap3 + 2 * 3;
 175             lum += -wrap + 2;
 176         }
 177         p += wrap3;
 178         lum += wrap;
 179     }
 180 }
 181
 182 int img_convert_to_yuv420(UINT8 *img_out, UINT8 *img,
 183                           int pix_fmt, int width, int height)
 184 {
 185     UINT8 *pict;
 186     int size, size_out;
 187     UINT8 *picture[3];
 188
 189     pict = img_out;
 190     size = width * height;
 191     size_out = (size * 3) / 2;
 192     picture[0] = pict;
 193     picture[1] = pict + size;
 194     picture[2] = picture[1] + (size / 4);
 195
 196     switch(pix_fmt) {
 197     case PIX_FMT_YUV420P:
 198         memcpy(pict, img, size_out);
 199         break;
 200     case PIX_FMT_YUV422:
 201         yuv422_to_yuv420p(picture[0], picture[1], picture[2],
 202                           img, width, height);
 203         break;
 204     case PIX_FMT_RGB24:
 205         rgb24_to_yuv420p(picture[0], picture[1], picture[2],
 206                          img, width, height);
 207         break;
 208     case PIX_FMT_BGR24:
 209         bgr24_to_yuv420p(picture[0], picture[1], picture[2],
 210                          img, width, height);
 211         break;
 212     }
 213     return size_out;
 214 }