1 files changed, 137 insertions, 0 deletions
diff --git a/third_party/aom/av1/encoder/k_means_template.h b/third_party/aom/av1/encoder/k_means_template.h
new file mode 100644
index 000000000..3a433d9b5
--- /dev/null
+++ b/third_party/aom/av1/encoder/k_means_template.h
@@ -0,0 +1,137 @@
+/*
+ * 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 <assert.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "av1/encoder/palette.h"
+#include "av1/encoder/random.h"
+
+#ifndef AV1_K_MEANS_DIM
+#error "This template requires AV1_K_MEANS_DIM to be defined"
+#endif
+
+#define RENAME_(x, y) AV1_K_MEANS_RENAME(x, y)
+#define RENAME(x) RENAME_(x, AV1_K_MEANS_DIM)
+
+static float RENAME(calc_dist)(const float *p1, const float *p2) {
+  float dist = 0;
+  int i;
+  for (i = 0; i < AV1_K_MEANS_DIM; ++i) {
+    const float diff = p1[i] - p2[i];
+    dist += diff * diff;
+  }
+  return dist;
+}
+
+void RENAME(av1_calc_indices)(const float *data, const float *centroids,
+                              uint8_t *indices, int n, int k) {
+  int i, j;
+  for (i = 0; i < n; ++i) {
+    float min_dist = RENAME(calc_dist)(data + i * AV1_K_MEANS_DIM, centroids);
+    indices[i] = 0;
+    for (j = 1; j < k; ++j) {
+      const float this_dist = RENAME(calc_dist)(
+          data + i * AV1_K_MEANS_DIM, centroids + j * AV1_K_MEANS_DIM);
+      if (this_dist < min_dist) {
+        min_dist = this_dist;
+        indices[i] = j;
+      }
+    }
+  }
+}
+
+static void RENAME(calc_centroids)(const float *data, float *centroids,
+                                   const uint8_t *indices, int n, int k) {
+  int i, j, index;
+  int count[PALETTE_MAX_SIZE];
+  unsigned int rand_state = (unsigned int)data[0];
+
+  assert(n <= 32768);
+
+  memset(count, 0, sizeof(count[0]) * k);
+  memset(centroids, 0, sizeof(centroids[0]) * k * AV1_K_MEANS_DIM);
+
+  for (i = 0; i < n; ++i) {
+    index = indices[i];
+    assert(index < k);
+    ++count[index];
+    for (j = 0; j < AV1_K_MEANS_DIM; ++j) {
+      centroids[index * AV1_K_MEANS_DIM + j] += data[i * AV1_K_MEANS_DIM + j];
+    }
+  }
+
+  for (i = 0; i < k; ++i) {
+    if (count[i] == 0) {
+      memcpy(centroids + i * AV1_K_MEANS_DIM,
+             data + (lcg_rand16(&rand_state) % n) * AV1_K_MEANS_DIM,
+             sizeof(centroids[0]) * AV1_K_MEANS_DIM);
+    } else {
+      const float norm = 1.0f / count[i];
+      for (j = 0; j < AV1_K_MEANS_DIM; ++j)
+        centroids[i * AV1_K_MEANS_DIM + j] *= norm;
+    }
+  }
+
+  // Round to nearest integers.
+  for (i = 0; i < k * AV1_K_MEANS_DIM; ++i) {
+    centroids[i] = roundf(centroids[i]);
+  }
+}
+
+static float RENAME(calc_total_dist)(const float *data, const float *centroids,
+                                     const uint8_t *indices, int n, int k) {
+  float dist = 0;
+  int i;
+  (void)k;
+
+  for (i = 0; i < n; ++i)
+    dist += RENAME(calc_dist)(data + i * AV1_K_MEANS_DIM,
+                              centroids + indices[i] * AV1_K_MEANS_DIM);
+
+  return dist;
+}
+
+void RENAME(av1_k_means)(const float *data, float *centroids, uint8_t *indices,
+                         int n, int k, int max_itr) {
+  int i;
+  float this_dist;
+  float pre_centroids[2 * PALETTE_MAX_SIZE];
+  uint8_t pre_indices[MAX_SB_SQUARE];
+
+  RENAME(av1_calc_indices)(data, centroids, indices, n, k);
+  this_dist = RENAME(calc_total_dist)(data, centroids, indices, n, k);
+
+  for (i = 0; i < max_itr; ++i) {
+    const float pre_dist = this_dist;
+    memcpy(pre_centroids, centroids,
+           sizeof(pre_centroids[0]) * k * AV1_K_MEANS_DIM);
+    memcpy(pre_indices, indices, sizeof(pre_indices[0]) * n);
+
+    RENAME(calc_centroids)(data, centroids, indices, n, k);
+    RENAME(av1_calc_indices)(data, centroids, indices, n, k);
+    this_dist = RENAME(calc_total_dist)(data, centroids, indices, n, k);
+
+    if (this_dist > pre_dist) {
+      memcpy(centroids, pre_centroids,
+             sizeof(pre_centroids[0]) * k * AV1_K_MEANS_DIM);
+      memcpy(indices, pre_indices, sizeof(pre_indices[0]) * n);
+      break;
+    }
+    if (!memcmp(centroids, pre_centroids,
+                sizeof(pre_centroids[0]) * k * AV1_K_MEANS_DIM))
+      break;
+  }
+}
+
+#undef RENAME_
+#undef RENAME