1// Copyright 2010 Google Inc. All Rights Reserved. 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) 15extern "C" { 16#endif 17 18enum { YUV_HALF = 1 << (YUV_FIX - 1) }; 19 20int16_t VP8kVToR[256], VP8kUToB[256]; 21int32_t VP8kVToG[256], VP8kUToG[256]; 22uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN]; 23uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN]; 24 25static int done = 0; 26 27static WEBP_INLINE uint8_t clip(int v, int max_value) { 28 return v < 0 ? 0 : v > max_value ? max_value : v; 29} 30 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