1 // Copyright 2010 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // YUV->RGB conversion function 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #include "./yuv.h" 15 16 #if defined(__cplusplus) || defined(c_plusplus) 17 extern "C" { 18 #endif 19 20 #ifdef WEBP_YUV_USE_TABLE 21 22 int16_t VP8kVToR[256], VP8kUToB[256]; 23 int32_t VP8kVToG[256], VP8kUToG[256]; 24 uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN]; 25 uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN]; 26 27 static int done = 0; 28 29 static WEBP_INLINE uint8_t clip(int v, int max_value) { 30 return v < 0 ? 0 : v > max_value ? max_value : v; 31 } 32 33 void VP8YUVInit(void) { 34 int i; 35 if (done) { 36 return; 37 } 38 #ifndef USE_YUVj 39 for (i = 0; i < 256; ++i) { 40 VP8kVToR[i] = (89858 * (i - 128) + YUV_HALF) >> YUV_FIX; 41 VP8kUToG[i] = -22014 * (i - 128) + YUV_HALF; 42 VP8kVToG[i] = -45773 * (i - 128); 43 VP8kUToB[i] = (113618 * (i - 128) + YUV_HALF) >> YUV_FIX; 44 } 45 for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) { 46 const int k = ((i - 16) * 76283 + YUV_HALF) >> YUV_FIX; 47 VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255); 48 VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15); 49 } 50 #else 51 for (i = 0; i < 256; ++i) { 52 VP8kVToR[i] = (91881 * (i - 128) + YUV_HALF) >> YUV_FIX; 53 VP8kUToG[i] = -22554 * (i - 128) + YUV_HALF; 54 VP8kVToG[i] = -46802 * (i - 128); 55 VP8kUToB[i] = (116130 * (i - 128) + YUV_HALF) >> YUV_FIX; 56 } 57 for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) { 58 const int k = i; 59 VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255); 60 VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15); 61 } 62 #endif 63 64 done = 1; 65 } 66 67 #else 68 69 void VP8YUVInit(void) {} 70 71 #endif // WEBP_YUV_USE_TABLE 72 73 #if defined(__cplusplus) || defined(c_plusplus) 74 } // extern "C" 75 #endif 76
