| 1 | // Copyright 2022 Google Inc. All Rights Reserved. |
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| 2 | // |
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| 3 | // Use of this source code is governed by a BSD-style license |
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| 4 | // that can be found in the COPYING file in the root of the source |
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| 5 | // tree. An additional intellectual property rights grant can be found |
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| 6 | // in the file PATENTS. All contributing project authors may |
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| 7 | // be found in the AUTHORS file in the root of the source tree. |
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| 8 | // ----------------------------------------------------------------------------- |
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| 9 | // |
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| 10 | // Colorspace utilities. |
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| 11 | |
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| 12 | #ifndef WEBP_SHARPYUV_SHARPYUV_CSP_H_ |
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| 13 | #define WEBP_SHARPYUV_SHARPYUV_CSP_H_ |
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| 14 | |
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| 15 | #include "sharpyuv/sharpyuv.h" |
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| 16 | |
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| 17 | #ifdef __cplusplus |
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| 18 | extern "C" { |
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| 19 | #endif |
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| 20 | |
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| 21 | // Range of YUV values. |
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| 22 | typedef enum { |
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| 23 | kSharpYuvRangeFull, // YUV values between [0;255] (for 8 bit) |
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| 24 | kSharpYuvRangeLimited // Y in [16;235], YUV in [16;240] (for 8 bit) |
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| 25 | } SharpYuvRange; |
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| 26 | |
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| 27 | // Constants that define a YUV color space. |
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| 28 | typedef struct { |
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| 29 | // Kr and Kb are defined such that: |
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| 30 | // Y = Kr * r + Kg * g + Kb * b where Kg = 1 - Kr - Kb. |
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| 31 | float kr; |
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| 32 | float kb; |
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| 33 | int bit_depth; // 8, 10 or 12 |
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| 34 | SharpYuvRange range; |
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| 35 | } SharpYuvColorSpace; |
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| 36 | |
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| 37 | // Fills in 'matrix' for the given YUVColorSpace. |
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| 38 | SHARPYUV_EXTERN void SharpYuvComputeConversionMatrix( |
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| 39 | const SharpYuvColorSpace* yuv_color_space, |
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| 40 | SharpYuvConversionMatrix* matrix); |
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| 41 | |
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| 42 | // Enums for precomputed conversion matrices. |
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| 43 | typedef enum { |
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| 44 | // WebP's matrix, similar but not identical to kSharpYuvMatrixRec601Limited |
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| 45 | kSharpYuvMatrixWebp = 0, |
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| 46 | // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeLimited |
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| 47 | kSharpYuvMatrixRec601Limited, |
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| 48 | // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeFull |
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| 49 | kSharpYuvMatrixRec601Full, |
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| 50 | // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeLimited |
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| 51 | kSharpYuvMatrixRec709Limited, |
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| 52 | // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeFull |
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| 53 | kSharpYuvMatrixRec709Full, |
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| 54 | kSharpYuvMatrixNum |
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| 55 | } SharpYuvMatrixType; |
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| 56 | |
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| 57 | // Returns a pointer to a matrix for one of the predefined colorspaces. |
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| 58 | SHARPYUV_EXTERN const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix( |
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| 59 | SharpYuvMatrixType matrix_type); |
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| 60 | |
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| 61 | #ifdef __cplusplus |
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| 62 | } // extern "C" |
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| 63 | #endif |
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| 64 | |
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| 65 | #endif // WEBP_SHARPYUV_SHARPYUV_CSP_H_ |
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| 66 | |
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