1 // Copyright 2010 Google Inc. 2 // 3 // This code is licensed under the same terms as WebM: 4 // Software License Agreement: http://www.webmproject.org/license/software/ 5 // Additional IP Rights Grant: http://www.webmproject.org/license/additional/ 6 // ----------------------------------------------------------------------------- 7 // 8 // YUV->RGB conversion function 9 // 10 // Author: Skal (pascal.massimino@gmail.com) 11 12 #include "yuv.h" 13 14 #if defined(__cplusplus) || defined(c_plusplus) 15 extern "C" { 16 #endif 17 18 enum { YUV_HALF = 1 << (YUV_FIX - 1) }; 19 20 int16_t VP8kVToR[256], VP8kUToB[256]; 21 int32_t VP8kVToG[256], VP8kUToG[256]; 22 uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN]; 23 uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN]; 24 25 static int done = 0; 26 clip(int v,int max_value)27static inline uint8_t clip(int v, int max_value) { 28 return v < 0 ? 0 : v > max_value ? max_value : v; 29 } 30 VP8YUVInit(void)31void VP8YUVInit(void) { 32 int i; 33 if (done) { 34 return; 35 } 36 for (i = 0; i < 256; ++i) { 37 VP8kVToR[i] = (89858 * (i - 128) + YUV_HALF) >> YUV_FIX; 38 VP8kUToG[i] = -22014 * (i - 128) + YUV_HALF; 39 VP8kVToG[i] = -45773 * (i - 128); 40 VP8kUToB[i] = (113618 * (i - 128) + YUV_HALF) >> YUV_FIX; 41 } 42 for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) { 43 const int k = ((i - 16) * 76283 + YUV_HALF) >> YUV_FIX; 44 VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255); 45 VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15); 46 } 47 done = 1; 48 } 49 50 #if defined(__cplusplus) || defined(c_plusplus) 51 } // extern "C" 52 #endif 53