mirror of
https://github.com/webmproject/libwebp.git
synced 2025-10-31 10:25:46 +01:00
0c8b0e67a4
Remove unused constants. Use ALL_CAPS for defines and kCamelCase for static const values. Change some defines into static constants if they are not used in array sizes. Change-Id: I036b0f99215fd0414a33f099bd6b809ff8ee4541
112 lines
3.7 KiB
C
112 lines
3.7 KiB
C
// Copyright 2022 Google Inc. All Rights Reserved.
|
|
//
|
|
// Use of this source code is governed by a BSD-style license
|
|
// that can be found in the COPYING file in the root of the source
|
|
// tree. An additional intellectual property rights grant can be found
|
|
// in the file PATENTS. All contributing project authors may
|
|
// be found in the AUTHORS file in the root of the source tree.
|
|
// -----------------------------------------------------------------------------
|
|
//
|
|
// Colorspace utilities.
|
|
|
|
#include "sharpyuv/sharpyuv_csp.h"
|
|
|
|
#include <assert.h>
|
|
#include <math.h>
|
|
#include <string.h>
|
|
|
|
static int ToFixed16(float f) { return (int)round(f * (1 << 16)); }
|
|
|
|
void SharpYuvComputeConversionMatrix(const SharpYuvColorSpace* yuv_color_space,
|
|
SharpYuvConversionMatrix* matrix) {
|
|
const float kr = yuv_color_space->kr;
|
|
const float kb = yuv_color_space->kb;
|
|
const float kg = 1.0f - kr - kb;
|
|
const float cr = 0.5f / (1.0f - kb);
|
|
const float cb = 0.5f / (1.0f - kr);
|
|
|
|
const int shift = yuv_color_space->bits - 8;
|
|
|
|
const float denom = (float)((1 << yuv_color_space->bits) - 1);
|
|
float scale_y = 1.0f;
|
|
float addY = 0.0f;
|
|
float scale_u = cr;
|
|
float scale_v = cb;
|
|
float add_uv = (float)(128 << shift);
|
|
|
|
assert(yuv_color_space->bits >= 8);
|
|
|
|
if (yuv_color_space->range == kSharpYuvRangeLimited) {
|
|
scale_y *= (219 << shift) / denom;
|
|
scale_u *= (224 << shift) / denom;
|
|
scale_v *= (224 << shift) / denom;
|
|
addY = (float)(16 << shift);
|
|
}
|
|
|
|
matrix->rgb_to_y[0] = ToFixed16(kr * scale_y);
|
|
matrix->rgb_to_y[1] = ToFixed16(kg * scale_y);
|
|
matrix->rgb_to_y[2] = ToFixed16(kb * scale_y);
|
|
matrix->rgb_to_y[3] = ToFixed16(addY);
|
|
|
|
matrix->rgb_to_u[0] = ToFixed16(-kr * scale_u);
|
|
matrix->rgb_to_u[1] = ToFixed16(-kg * scale_u);
|
|
matrix->rgb_to_u[2] = ToFixed16((1 - kb) * scale_u);
|
|
matrix->rgb_to_u[3] = ToFixed16(add_uv);
|
|
|
|
matrix->rgb_to_v[0] = ToFixed16((1 - kr) * scale_v);
|
|
matrix->rgb_to_v[1] = ToFixed16(-kg * scale_v);
|
|
matrix->rgb_to_v[2] = ToFixed16(-kb * scale_v);
|
|
matrix->rgb_to_v[3] = ToFixed16(add_uv);
|
|
}
|
|
|
|
// Matrices are in YUV_FIX fixed point precision.
|
|
// WebP's matrix, similar but not identical to kRec601LimitedMatrix.
|
|
static const SharpYuvConversionMatrix kWebpMatrix = {
|
|
{16839, 33059, 6420, 16 << 16},
|
|
{-9719, -19081, 28800, 128 << 16},
|
|
{28800, -24116, -4684, 128 << 16},
|
|
};
|
|
// Kr=0.2990f Kb=0.1140f btits=8 range=kLimited
|
|
static const SharpYuvConversionMatrix kRec601LimitedMatrix = {
|
|
{16829, 33039, 6416, 16 << 16},
|
|
{-9714, -19071, 28784, 128 << 16},
|
|
{28784, -24103, -4681, 128 << 16},
|
|
};
|
|
// Kr=0.2990f Kb=0.1140f btits=8 range=kFull
|
|
static const SharpYuvConversionMatrix kRec601FullMatrix = {
|
|
{19595, 38470, 7471, 0},
|
|
{-11058, -21710, 32768, 128 << 16},
|
|
{32768, -27439, -5329, 128 << 16},
|
|
};
|
|
// Kr=0.2126f Kb=0.0722f bits=8 range=kLimited
|
|
static const SharpYuvConversionMatrix kRec709LimitedMatrix = {
|
|
{11966, 40254, 4064, 16 << 16},
|
|
{-6596, -22189, 28784, 128 << 16},
|
|
{28784, -26145, -2639, 128 << 16},
|
|
};
|
|
// Kr=0.2126f Kb=0.0722f bits=8 range=kFull
|
|
static const SharpYuvConversionMatrix kRec709FullMatrix = {
|
|
{13933, 46871, 4732, 0},
|
|
{-7509, -25259, 32768, 128 << 16},
|
|
{32768, -29763, -3005, 128 << 16},
|
|
};
|
|
|
|
const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix(
|
|
SharpYuvMatrixType matrix_type) {
|
|
switch (matrix_type) {
|
|
case kSharpYuvMatrixWebp:
|
|
return &kWebpMatrix;
|
|
case kSharpYuvMatrixRec601Limited:
|
|
return &kRec601LimitedMatrix;
|
|
case kSharpYuvMatrixRec601Full:
|
|
return &kRec601FullMatrix;
|
|
case kSharpYuvMatrixRec709Limited:
|
|
return &kRec709LimitedMatrix;
|
|
case kSharpYuvMatrixRec709Full:
|
|
return &kRec709FullMatrix;
|
|
case kSharpYuvMatrixNum:
|
|
return NULL;
|
|
}
|
|
return NULL;
|
|
}
|