Eric Hassold | 9aea642 | 2011-01-04 17:22:46 -0800 | [diff] [blame^] | 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 | |
| 24 | static int done = 0; |
| 25 | |
| 26 | void VP8YUVInit() { |
| 27 | int i; |
| 28 | if (done) { |
| 29 | return; |
| 30 | } |
| 31 | for (i = 0; i < 256; ++i) { |
| 32 | VP8kVToR[i] = (89858 * (i - 128) + YUV_HALF) >> YUV_FIX; |
| 33 | VP8kUToG[i] = -22014 * (i - 128) + YUV_HALF; |
| 34 | VP8kVToG[i] = -45773 * (i - 128); |
| 35 | VP8kUToB[i] = (113618 * (i - 128) + YUV_HALF) >> YUV_FIX; |
| 36 | } |
| 37 | for (i = YUV_RANGE_MIN; i < YUV_RANGE_MAX; ++i) { |
| 38 | const int k = ((i - 16) * 76283 + YUV_HALF) >> YUV_FIX; |
| 39 | VP8kClip[i - YUV_RANGE_MIN] = (k < 0) ? 0 : (k > 255) ? 255 : k; |
| 40 | } |
| 41 | done = 1; |
| 42 | } |
| 43 | |
| 44 | #if defined(__cplusplus) || defined(c_plusplus) |
| 45 | } // extern "C" |
| 46 | #endif |