/**************************************************************************/
/* rgb2yuv.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/**************************************************************************/
#pragma once
#include "core/typedefs.h"
// For reference, see:
// - https://stackoverflow.com/a/9467305
// - https://en.wikipedia.org/wiki/YCbCr#Approximate_8-bit_matrices_for_BT.601
static void _rgb2yuv420(uint8_t *y, uint8_t *u, uint8_t *v, uint8_t *rgb, size_t width, size_t height, size_t pixel_size) {
size_t uvpos = 0;
size_t i = 0;
for (size_t line = 0; line < height; line += 2) {
for (size_t x = 0; x < width; x += 2) {
uint8_t r = rgb[pixel_size * i];
uint8_t g = rgb[pixel_size * i + 1];
uint8_t b = rgb[pixel_size * i + 2];
y[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
u[uvpos] = ((-38 * r + -74 * g + 112 * b) >> 8) + 128;
v[uvpos] = ((112 * r + -94 * g + -18 * b) >> 8) + 128;
uvpos++;
r = rgb[pixel_size * i];
g = rgb[pixel_size * i + 1];
b = rgb[pixel_size * i + 2];
y[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
}
for (size_t x = 0; x < width; x += 1) {
uint8_t r = rgb[pixel_size * i];
uint8_t g = rgb[pixel_size * i + 1];
uint8_t b = rgb[pixel_size * i + 2];
y[i++] = ((66 * r + 129 * g + 25 * b) >> 8) + 16;
}
}
}
static void rgb2yuv420(uint8_t *y, uint8_t *u, uint8_t *v, uint8_t *rgb, size_t width, size_t height) {
_rgb2yuv420(y, u, v, rgb, width, height, 3);
}
static void rgba2yuv420(uint8_t *y, uint8_t *u, uint8_t *v, uint8_t *rgba, size_t width, size_t height) {
_rgb2yuv420(y, u, v, rgba, width, height, 4);
}