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-rw-r--r--third_party/aom/aom_dsp/add_noise.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/add_noise.c b/third_party/aom/aom_dsp/add_noise.c
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+++ b/third_party/aom/aom_dsp/add_noise.c
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+/*
+ * 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 * 3.14159265)) *
+ (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];
+}