Add libaom ML framework

av1/encoder/ml.c

+/*
+ * 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 "av1/encoder/ml.h"
+
+void av1_nn_predict(const float *features, const NN_CONFIG *nn_config,
+                    float *output) {
+  int num_input_nodes = nn_config->num_inputs;
+  int buf_index = 0;
+  float buf[2][NN_MAX_NODES_PER_LAYER];
+  const float *input_nodes = features;
+
+  // Propagate hidden layers.
+  const int num_layers = nn_config->num_hidden_layers;
+  assert(num_layers <= NN_MAX_HIDDEN_LAYERS);
+  for (int layer = 0; layer < num_layers; ++layer) {
+    const float *weights = nn_config->weights[layer];
+    const float *bias = nn_config->bias[layer];
+    float *output_nodes = buf[buf_index];
+    const int num_output_nodes = nn_config->num_hidden_nodes[layer];
+    assert(num_output_nodes < NN_MAX_NODES_PER_LAYER);
+    for (int node = 0; node < num_output_nodes; ++node) {
+      float val = 0.0f;
+      for (int i = 0; i < num_input_nodes; ++i)
+        val += weights[i] * input_nodes[i];
+      val += bias[node];
+      // ReLU as activation function.
+      val = val > 0.0f ? val : 0.0f;  // Could use AOMMAX().
+      output_nodes[node] = val;
+      weights += num_input_nodes;
+    }
+    num_input_nodes = num_output_nodes;
+    input_nodes = output_nodes;
+    buf_index = 1 - buf_index;
+  }
+
+  // Final output layer.
+  const float *weights = nn_config->weights[num_layers];
+  for (int node = 0; node < nn_config->num_outputs; ++node) {
+    const float *bias = nn_config->bias[num_layers];
+    float val = 0.0f;
+    for (int i = 0; i < num_input_nodes; ++i)
+      val += weights[i] * input_nodes[i];
+    output[node] = val + bias[node];
+    weights += num_input_nodes;
+  }
+}

av1/encoder/ml.h

+/*
+ * 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.
+ */
+
+#ifndef AV1_ENCODER_ML_H_
+#define AV1_ENCODER_ML_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define NN_MAX_HIDDEN_LAYERS 10
+#define NN_MAX_NODES_PER_LAYER 128
+
+typedef struct {
+  int num_inputs;         // Number of input nodes, i.e. features.
+  int num_outputs;        // Number of output nodes.
+  int num_hidden_layers;  // Number of hidden layers, maximum 10.
+  // Number of nodes for each hidden layer.
+  int num_hidden_nodes[NN_MAX_HIDDEN_LAYERS];
+  // Weight parameters, indexed by layer.
+  const float *weights[NN_MAX_HIDDEN_LAYERS + 1];
+  // Bias parameters, indexed by layer.
+  const float *bias[NN_MAX_HIDDEN_LAYERS + 1];
+} NN_CONFIG;
+
+// Calculate prediction based on the given input features and neural net config.
+// Assume there are no more than NN_MAX_NODES_PER_LAYER nodes in each hidden
+// layer.
+void av1_nn_predict(const float *features, const NN_CONFIG *nn_config,
+                    float *output);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // AV1_ENCODER_RD_H_