gfx/ycbcr/yuv_row_c.cpp

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "yuv_row.h"
   6
   7 #define DCHECK(a)
   8
   9 extern "C" {
  10
  11 // C reference code that mimic the YUV assembly.
  12 #define packuswb(x) ((x) < 0 ? 0 : ((x) > 255 ? 255 : (x)))
  13 #define paddsw(x, y) (((x) + (y)) < -32768 ? -32768 : \
  14     (((x) + (y)) > 32767 ? 32767 : ((x) + (y))))
  15
  16 static inline void YuvPixel(uint8 y,
  17                             uint8 u,
  18                             uint8 v,
  19                             uint8* rgb_buf) {
  20
  21   int b = kCoefficientsRgbY[256+u][0];
  22   int g = kCoefficientsRgbY[256+u][1];
  23   int r = kCoefficientsRgbY[256+u][2];
  24   int a = kCoefficientsRgbY[256+u][3];
  25
  26   b = paddsw(b, kCoefficientsRgbY[512+v][0]);
  27   g = paddsw(g, kCoefficientsRgbY[512+v][1]);
  28   r = paddsw(r, kCoefficientsRgbY[512+v][2]);
  29   a = paddsw(a, kCoefficientsRgbY[512+v][3]);
  30
  31   b = paddsw(b, kCoefficientsRgbY[y][0]);
  32   g = paddsw(g, kCoefficientsRgbY[y][1]);
  33   r = paddsw(r, kCoefficientsRgbY[y][2]);
  34   a = paddsw(a, kCoefficientsRgbY[y][3]);
  35
  36   b >>= 6;
  37   g >>= 6;
  38   r >>= 6;
  39   a >>= 6;
  40
  41   *reinterpret_cast<uint32*>(rgb_buf) = (packuswb(b)) |
  42                                         (packuswb(g) << 8) |
  43                                         (packuswb(r) << 16) |
  44                                         (packuswb(a) << 24);
  45 }
  46
  47 void FastConvertYUVToRGB32Row_C(const uint8* y_buf,
  48                                 const uint8* u_buf,
  49                                 const uint8* v_buf,
  50                                 uint8* rgb_buf,
  51                                 int width,
  52                                 unsigned int x_shift) {
  53   for (int x = 0; x < width; x += 2) {
  54     uint8 u = u_buf[x >> x_shift];
  55     uint8 v = v_buf[x >> x_shift];
  56     uint8 y0 = y_buf[x];
  57     YuvPixel(y0, u, v, rgb_buf);
  58     if ((x + 1) < width) {
  59       uint8 y1 = y_buf[x + 1];
  60       if (x_shift == 0) {
  61         u = u_buf[x + 1];
  62         v = v_buf[x + 1];
  63       }
  64       YuvPixel(y1, u, v, rgb_buf + 4);
  65     }
  66     rgb_buf += 8;  // Advance 2 pixels.
  67   }
  68 }
  69
  70 // 16.16 fixed point is used.  A shift by 16 isolates the integer.
  71 // A shift by 17 is used to further subsample the chrominence channels.
  72 // & 0xffff isolates the fixed point fraction.  >> 2 to get the upper 2 bits,
  73 // for 1/65536 pixel accurate interpolation.
  74 void ScaleYUVToRGB32Row_C(const uint8* y_buf,
  75                           const uint8* u_buf,
  76                           const uint8* v_buf,
  77                           uint8* rgb_buf,
  78                           int width,
  79                           int source_dx) {
  80   int x = 0;
  81   for (int i = 0; i < width; i += 2) {
  82     int y = y_buf[x >> 16];
  83     int u = u_buf[(x >> 17)];
  84     int v = v_buf[(x >> 17)];
  85     YuvPixel(y, u, v, rgb_buf);
  86     x += source_dx;
  87     if ((i + 1) < width) {
  88       y = y_buf[x >> 16];
  89       YuvPixel(y, u, v, rgb_buf+4);
  90       x += source_dx;
  91     }
  92     rgb_buf += 8;
  93   }
  94 }
  95
  96 void LinearScaleYUVToRGB32Row_C(const uint8* y_buf,
  97                                 const uint8* u_buf,
  98                                 const uint8* v_buf,
  99                                 uint8* rgb_buf,
 100                                 int width,
 101                                 int source_dx) {
 102   int x = 0;
 103   if (source_dx >= 0x20000) {
 104     x = 32768;
 105   }
 106   for (int i = 0; i < width; i += 2) {
 107     int y0 = y_buf[x >> 16];
 108     int y1 = y_buf[(x >> 16) + 1];
 109     int u0 = u_buf[(x >> 17)];
 110     int u1 = u_buf[(x >> 17) + 1];
 111     int v0 = v_buf[(x >> 17)];
 112     int v1 = v_buf[(x >> 17) + 1];
 113     int y_frac = (x & 65535);
 114     int uv_frac = ((x >> 1) & 65535);
 115     int y = (y_frac * y1 + (y_frac ^ 65535) * y0) >> 16;
 116     int u = (uv_frac * u1 + (uv_frac ^ 65535) * u0) >> 16;
 117     int v = (uv_frac * v1 + (uv_frac ^ 65535) * v0) >> 16;
 118     YuvPixel(y, u, v, rgb_buf);
 119     x += source_dx;
 120     if ((i + 1) < width) {
 121       y0 = y_buf[x >> 16];
 122       y1 = y_buf[(x >> 16) + 1];
 123       y_frac = (x & 65535);
 124       y = (y_frac * y1 + (y_frac ^ 65535) * y0) >> 16;
 125       YuvPixel(y, u, v, rgb_buf+4);
 126       x += source_dx;
 127     }
 128     rgb_buf += 8;
 129   }
 130 }
 131
 132 }  // extern "C"
 133