yuv_row_c.cpp (4172B)
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_t y, 17 uint8_t u, 18 uint8_t v, 19 uint8_t* 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_t*>(rgb_buf) = (packuswb(b)) | 42 (packuswb(g) << 8) | 43 (packuswb(r) << 16) | 44 (packuswb(a) << 24); 45 } 46 47 void FastConvertYUVToRGB32Row_C(const uint8_t* y_buf, 48 const uint8_t* u_buf, 49 const uint8_t* v_buf, 50 uint8_t* rgb_buf, 51 int width, 52 unsigned int x_shift) { 53 for (int x = 0; x < width; x += 2) { 54 uint8_t u = u_buf[x >> x_shift]; 55 uint8_t v = v_buf[x >> x_shift]; 56 uint8_t y0 = y_buf[x]; 57 YuvPixel(y0, u, v, rgb_buf); 58 if ((x + 1) < width) { 59 uint8_t 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_t* y_buf, 75 const uint8_t* u_buf, 76 const uint8_t* v_buf, 77 uint8_t* 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_t* y_buf, 97 const uint8_t* u_buf, 98 const uint8_t* v_buf, 99 uint8_t* 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"