// // Created by xu fulong on 2022/7/8. // #include "yuv_to_rgb.h" // https://chromium.googlesource.com/libyuv/libyuv // https://mymusing.co/bt601-yuv-to-rgb-conversion-color/ // https://www.color.org/chardata/rgb/rgb_registry.xalter // BT.601 YUV to RGB // R = 1.164 * (Y - 16) + 1.596 * (V - 128) // G = 1.164 * (Y - 16) - 0.392 * (U - 128) - 0.812 * (V - 128) // B = 1.164 * (Y - 16) + 2.016 * (U - 128) // Y = 0.257 * R + 0.504 * G + 0.098 * B + 16 // U = -0.148 * R - 0.291 * G + 0.439 * B + 128 // V = 0.439 * R - 0.368 * G - 0.072 * B + 128 // BT.709 YUV to RGB // R = 1.1644 * (Y - 16) + 1.7928 * (V - 128) // G = 1.1644 * (Y - 16) - 0.2133 * (U - 128) - 0.533 * (V - 128) // B = 1.1644 * (Y - 16) + 2.1124 * (U - 128) // Y = 0.1826 * R + 0.6142 * G + 0.0620 * B + 16 // U = -0.1006 * R - 0.3386 * G + 0.4392 * B + 128 // V = 0.4392 * B - 0.3989 * G - 0.0403 * B + 128 // BT.2020 YUV to RGB // R = Y - 16 + 1.4746 * (V - 128) // G = Y - 16 - 0.1645 * (U - 128) - 0.5713 * (V - 128) // B = Y - 16 + 1.881 * (U - 128) // Y = 0.2627 * R + 0.6780 * G + 0.0593 * B + 16 // U = -0.1396 * R - 0.3604 * G + 0.5 * B + 128 // V = 0.5 * R - 0.4598 * G - 0.0402 * B + 128 static int range(int val) { if (val < 0) { return 0; } else if (val > 255) { return 255; } else { return val; } } static void YCbCr_to_RGB(uint8_t *dst, const uint8_t *src, int length) { if (length < 1) return; int R, G, B; int Y, Cb, Cr; int i, offset; for (i = 0; i < length; i++) { offset = (i << 1) + i; Y = src[offset]; Cb = src[offset + 1] - 128; Cr = src[offset + 2] - 128; R = Y + ((RGBRCrI * Cr + half_shift) >> shift); G = Y + ((RGBGCbI * Cb + RGBGCrI * Cr + half_shift) >> shift); B = Y + ((RGBBCbI * Cb + half_shift) >> shift); R = range(R); G = range(G); B = range(B); offset = i << 2; dst[offset] = (uint8_t) B; dst[offset + 1] = (uint8_t) G; dst[offset + 2] = (uint8_t) R; dst[offset + 3] = 0xff; } } static void RGB_to_YCbCr(uint8_t *dst, const uint8_t *src, int length) { if (length < 1) return; int R, G, B; int i, offset; for (i = 0; i < length; i++) { offset = i << 2; B = src[offset]; G = src[offset + 1]; R = src[offset + 2]; offset = (i << 1) + i; dst[offset] = (uint8_t) ((YCbCrYRI * R + YCbCrYGI * G + YCbCrYBI * B + half_shift) >> shift); dst[offset + 1] = (uint8_t) (128 + ((YCbCrCbRI * R + YCbCrCbGI * G + YCbCrCbBI * B + half_shift) >> shift)); dst[offset + 2] = (uint8_t) (128 + ((YCbCrCrRI * R + YCbCrCrGI * G + YCbCrCrBI * B + half_shift) >> shift)); } }