| /* |
| * Copyright (c) 2016, Alliance for Open Media. All rights reserved |
| * |
| * This source code is subject to the terms of the BSD 2 Clause License and |
| * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License |
| * was not distributed with this source code in the LICENSE file, you can |
| * obtain it at www.aomedia.org/license/software. If the Alliance for Open |
| * Media Patent License 1.0 was not distributed with this source code in the |
| * PATENTS file, you can obtain it at www.aomedia.org/license/patent. |
| */ |
| |
| #include <math.h> |
| #include <stdlib.h> |
| |
| #include "config/aom_config.h" |
| #include "config/aom_dsp_rtcd.h" |
| |
| #include "aom/aom_integer.h" |
| #include "aom_ports/mem.h" |
| |
| void aom_plane_add_noise_c(uint8_t *start, char *noise, char blackclamp[16], |
| char whiteclamp[16], char bothclamp[16], |
| unsigned int width, unsigned int height, int pitch) { |
| unsigned int i, j; |
| |
| for (i = 0; i < height; ++i) { |
| uint8_t *pos = start + i * pitch; |
| char *ref = (char *)(noise + (rand() & 0xff)); // NOLINT |
| |
| for (j = 0; j < width; ++j) { |
| int v = pos[j]; |
| |
| v = clamp(v - blackclamp[0], 0, 255); |
| v = clamp(v + bothclamp[0], 0, 255); |
| v = clamp(v - whiteclamp[0], 0, 255); |
| |
| pos[j] = v + ref[j]; |
| } |
| } |
| } |
| |
| static double gaussian(double sigma, double mu, double x) { |
| return 1 / (sigma * sqrt(2.0 * PI)) * |
| (exp(-(x - mu) * (x - mu) / (2 * sigma * sigma))); |
| } |
| |
| int aom_setup_noise(double sigma, int size, char *noise) { |
| char char_dist[256]; |
| int next = 0, i, j; |
| |
| // set up a 256 entry lookup that matches gaussian distribution |
| for (i = -32; i < 32; ++i) { |
| const int a_i = (int)(0.5 + 256 * gaussian(sigma, 0, i)); |
| if (a_i) { |
| for (j = 0; j < a_i; ++j) { |
| char_dist[next + j] = (char)i; |
| } |
| next = next + j; |
| } |
| } |
| |
| // Rounding error - might mean we have less than 256. |
| for (; next < 256; ++next) { |
| char_dist[next] = 0; |
| } |
| |
| for (i = 0; i < size; ++i) { |
| noise[i] = char_dist[rand() & 0xff]; // NOLINT |
| } |
| |
| // Returns the highest non 0 value used in distribution. |
| return -char_dist[0]; |
| } |