1 // Copyright 2022 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 // Colorspace utilities. 11 12 #ifndef WEBP_SHARPYUV_SHARPYUV_CSP_H_ 13 #define WEBP_SHARPYUV_SHARPYUV_CSP_H_ 14 15 #include "sharpyuv/sharpyuv.h" 16 17 #ifdef __cplusplus 18 extern "C" { 19 #endif 20 21 // Range of YUV values. 22 typedef enum { 23 kSharpYuvRangeFull, // YUV values between [0;255] (for 8 bit) 24 kSharpYuvRangeLimited // Y in [16;235], YUV in [16;240] (for 8 bit) 25 } SharpYuvRange; 26 27 // Constants that define a YUV color space. 28 typedef struct { 29 // Kr and Kb are defined such that: 30 // Y = Kr * r + Kg * g + Kb * b where Kg = 1 - Kr - Kb. 31 float kr; 32 float kb; 33 int bit_depth; // 8, 10 or 12 34 SharpYuvRange range; 35 } SharpYuvColorSpace; 36 37 // Fills in 'matrix' for the given YUVColorSpace. 38 SHARPYUV_EXTERN void SharpYuvComputeConversionMatrix( 39 const SharpYuvColorSpace* yuv_color_space, 40 SharpYuvConversionMatrix* matrix); 41 42 // Enums for precomputed conversion matrices. 43 typedef enum { 44 // WebP's matrix, similar but not identical to kSharpYuvMatrixRec601Limited 45 kSharpYuvMatrixWebp = 0, 46 // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeLimited 47 kSharpYuvMatrixRec601Limited, 48 // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeFull 49 kSharpYuvMatrixRec601Full, 50 // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeLimited 51 kSharpYuvMatrixRec709Limited, 52 // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeFull 53 kSharpYuvMatrixRec709Full, 54 kSharpYuvMatrixNum 55 } SharpYuvMatrixType; 56 57 // Returns a pointer to a matrix for one of the predefined colorspaces. 58 SHARPYUV_EXTERN const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix( 59 SharpYuvMatrixType matrix_type); 60 61 #ifdef __cplusplus 62 } // extern "C" 63 #endif 64 65 #endif // WEBP_SHARPYUV_SHARPYUV_CSP_H_ 66