1 // Copyright 2010 Google Inc. All Rights Reserved.
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 // -----------------------------------------------------------------------------
10 // YUV->RGB conversion function
12 // Author: Skal (pascal.massimino@gmail.com)
16 #if defined(__cplusplus) || defined(c_plusplus)
20 #ifdef WEBP_YUV_USE_TABLE
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];
29 static WEBP_INLINE uint8_t clip(int v, int max_value) {
30 return v < 0 ? 0 : v > max_value ? max_value : v;
33 void VP8YUVInit(void) {
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;
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);
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;
57 for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) {
59 VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255);
60 VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15);
69 void VP8YUVInit(void) {}
71 #endif // WEBP_YUV_USE_TABLE
73 #if defined(__cplusplus) || defined(c_plusplus)