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// Copyright 2010 Google Inc. All Rights Reserved.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// YUV->RGB conversion function
//
// Author: Skal (pascal.massimino@gmail.com)
#include "./yuv.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
enum { YUV_HALF = 1 << (YUV_FIX - 1) };
int16_t VP8kVToR[256], VP8kUToB[256];
int32_t VP8kVToG[256], VP8kUToG[256];
uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN];
uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN];
static int done = 0;
static WEBP_INLINE uint8_t clip(int v, int max_value) {
return v < 0 ? 0 : v > max_value ? max_value : v;
}
void VP8YUVInit(void) {
int i;
if (done) {
return;
}
#ifndef USE_YUVj
for (i = 0; i < 256; ++i) {
VP8kVToR[i] = (89858 * (i - 128) + YUV_HALF) >> YUV_FIX;
VP8kUToG[i] = -22014 * (i - 128) + YUV_HALF;
VP8kVToG[i] = -45773 * (i - 128);
VP8kUToB[i] = (113618 * (i - 128) + YUV_HALF) >> YUV_FIX;
}
for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) {
const int k = ((i - 16) * 76283 + YUV_HALF) >> YUV_FIX;
VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255);
VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15);
}
#else
for (i = 0; i < 256; ++i) {
VP8kVToR[i] = (91881 * (i - 128) + YUV_HALF) >> YUV_FIX;
VP8kUToG[i] = -22554 * (i - 128) + YUV_HALF;
VP8kVToG[i] = -46802 * (i - 128);
VP8kUToB[i] = (116130 * (i - 128) + YUV_HALF) >> YUV_FIX;
}
for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) {
const int k = i;
VP8kClip[i - YUV_RANGE_MIN] = clip(k, 255);
VP8kClip4Bits[i - YUV_RANGE_MIN] = clip((k + 8) >> 4, 15);
}
#endif
done = 1;
}
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
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