Adding part of the rnnoise library in 3rd party

This CL adds part of the rnnoise library in 3rd party.
What is retained are pretrained parameters and a few
functions implementing a recurrent neural network.

Change-Id: I66c55958d13b7f120aa508f6d7afd7f13f59f659
Reviewed-on: https://chromium-review.googlesource.com/931553Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Ale Bzk <alessiob@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539174}

third_party/rnnoise/COPYING

+Copyright (c) 2017, Mozilla
+Copyright (c) 2007-2017, Jean-Marc Valin
+Copyright (c) 2005-2017, Xiph.Org Foundation
+Copyright (c) 2003-2004, Mark Borgerding
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+- Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+- Neither the name of the Xiph.Org Foundation nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION
+OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

third_party/rnnoise/OWNERS

+alessiob@chromium.org
+aleloi@chromium.org

third_party/rnnoise/README.chromium

+Name: Recurrent neural network for audio noise reduction
+Short Name: rnnoise
+URL: https://github.com/xiph/rnnoise
+Version: 91ef401
+Date: Oct 10, 2017
+Revision:
+License: BSD 3-Clause
+License File: COPYING
+Security Critical: no
+License Android Compatible:
+
+Description:
+RNNoise is a noise suppression library based on a recurrent neural network.
+The library is used for speech processing in WebRTC.
+
+Local Modifications:
+Only retaining rnn.c, rnn_data.c, tansig_table.h from src/ and COPYING.

third_party/rnnoise/src/rnn.c

+/* Copyright (c) 2008-2011 Octasic Inc.
+                 2012-2017 Jean-Marc Valin */
+/*
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <math.h>
+#include "opus_types.h"
+#include "common.h"
+#include "arch.h"
+#include "tansig_table.h"
+#include "rnn.h"
+#include "rnn_data.h"
+#include <stdio.h>
+
+static OPUS_INLINE float tansig_approx(float x)
+{
+    int i;
+    float y, dy;
+    float sign=1;
+    /* Tests are reversed to catch NaNs */
+    if (!(x<8))
+        return 1;
+    if (!(x>-8))
+        return -1;
+#ifndef FIXED_POINT
+    /* Another check in case of -ffast-math */
+    if (celt_isnan(x))
+       return 0;
+#endif
+    if (x<0)
+    {
+       x=-x;
+       sign=-1;
+    }
+    i = (int)floor(.5f+25*x);
+    x -= .04f*i;
+    y = tansig_table[i];
+    dy = 1-y*y;
+    y = y + x*dy*(1 - y*x);
+    return sign*y;
+}
+
+static OPUS_INLINE float sigmoid_approx(float x)
+{
+   return .5 + .5*tansig_approx(.5*x);
+}
+
+static OPUS_INLINE float relu(float x)
+{
+   return x < 0 ? 0 : x;
+}
+
+void compute_dense(const DenseLayer *layer, float *output, const float *input)
+{
+   int i, j;
+   int N, M;
+   int stride;
+   M = layer->nb_inputs;
+   N = layer->nb_neurons;
+   stride = N;
+   for (i=0;i<N;i++)
+   {
+      /* Compute update gate. */
+      float sum = layer->bias[i];
+      for (j=0;j<M;j++)
+         sum += layer->input_weights[j*stride + i]*input[j];
+      output[i] = WEIGHTS_SCALE*sum;
+   }
+   if (layer->activation == ACTIVATION_SIGMOID) {
+      for (i=0;i<N;i++)
+         output[i] = sigmoid_approx(output[i]);
+   } else if (layer->activation == ACTIVATION_TANH) {
+      for (i=0;i<N;i++)
+         output[i] = tansig_approx(output[i]);
+   } else if (layer->activation == ACTIVATION_RELU) {
+      for (i=0;i<N;i++)
+         output[i] = relu(output[i]);
+   } else {
+     *(int*)0=0;
+   }
+}
+
+void compute_gru(const GRULayer *gru, float *state, const float *input)
+{
+   int i, j;
+   int N, M;
+   int stride;
+   float z[MAX_NEURONS];
+   float r[MAX_NEURONS];
+   float h[MAX_NEURONS];
+   M = gru->nb_inputs;
+   N = gru->nb_neurons;
+   stride = 3*N;
+   for (i=0;i<N;i++)
+   {
+      /* Compute update gate. */
+      float sum = gru->bias[i];
+      for (j=0;j<M;j++)
+         sum += gru->input_weights[j*stride + i]*input[j];
+      for (j=0;j<N;j++)
+         sum += gru->recurrent_weights[j*stride + i]*state[j];
+      z[i] = sigmoid_approx(WEIGHTS_SCALE*sum);
+   }
+   for (i=0;i<N;i++)
+   {
+      /* Compute reset gate. */
+      float sum = gru->bias[N + i];
+      for (j=0;j<M;j++)
+         sum += gru->input_weights[N + j*stride + i]*input[j];
+      for (j=0;j<N;j++)
+         sum += gru->recurrent_weights[N + j*stride + i]*state[j];
+      r[i] = sigmoid_approx(WEIGHTS_SCALE*sum);
+   }
+   for (i=0;i<N;i++)
+   {
+      /* Compute output. */
+      float sum = gru->bias[2*N + i];
+      for (j=0;j<M;j++)
+         sum += gru->input_weights[2*N + j*stride + i]*input[j];
+      for (j=0;j<N;j++)
+         sum += gru->recurrent_weights[2*N + j*stride + i]*state[j]*r[j];
+      if (gru->activation == ACTIVATION_SIGMOID) sum = sigmoid_approx(WEIGHTS_SCALE*sum);
+      else if (gru->activation == ACTIVATION_TANH) sum = tansig_approx(WEIGHTS_SCALE*sum);
+      else if (gru->activation == ACTIVATION_RELU) sum = relu(WEIGHTS_SCALE*sum);
+      else *(int*)0=0;
+      h[i] = z[i]*state[i] + (1-z[i])*sum;
+   }
+   for (i=0;i<N;i++)
+      state[i] = h[i];
+}
+
+#define INPUT_SIZE 42
+
+void compute_rnn(RNNState *rnn, float *gains, float *vad, const float *input) {
+  int i;
+  float dense_out[MAX_NEURONS];
+  float noise_input[MAX_NEURONS*3];
+  float denoise_input[MAX_NEURONS*3];
+  compute_dense(&input_dense, dense_out, input);
+  compute_gru(&vad_gru, rnn->vad_gru_state, dense_out);
+  compute_dense(&vad_output, vad, rnn->vad_gru_state);
+  for (i=0;i<INPUT_DENSE_SIZE;i++) noise_input[i] = dense_out[i];
+  for (i=0;i<VAD_GRU_SIZE;i++) noise_input[i+INPUT_DENSE_SIZE] = rnn->vad_gru_state[i];
+  for (i=0;i<INPUT_SIZE;i++) noise_input[i+INPUT_DENSE_SIZE+VAD_GRU_SIZE] = input[i];
+  compute_gru(&noise_gru, rnn->noise_gru_state, noise_input);
+
+  for (i=0;i<VAD_GRU_SIZE;i++) denoise_input[i] = rnn->vad_gru_state[i];
+  for (i=0;i<NOISE_GRU_SIZE;i++) denoise_input[i+VAD_GRU_SIZE] = rnn->noise_gru_state[i];
+  for (i=0;i<INPUT_SIZE;i++) denoise_input[i+VAD_GRU_SIZE+NOISE_GRU_SIZE] = input[i];
+  compute_gru(&denoise_gru, rnn->denoise_gru_state, denoise_input);
+  compute_dense(&denoise_output, gains, rnn->denoise_gru_state);
+}

third_party/rnnoise/src/tansig_table.h

+/* This file is auto-generated by gen_tables */
+
+static const float tansig_table[201] = {
+0.000000f, 0.039979f, 0.079830f, 0.119427f, 0.158649f,
+0.197375f, 0.235496f, 0.272905f, 0.309507f, 0.345214f,
+0.379949f, 0.413644f, 0.446244f, 0.477700f, 0.507977f,
+0.537050f, 0.564900f, 0.591519f, 0.616909f, 0.641077f,
+0.664037f, 0.685809f, 0.706419f, 0.725897f, 0.744277f,
+0.761594f, 0.777888f, 0.793199f, 0.807569f, 0.821040f,
+0.833655f, 0.845456f, 0.856485f, 0.866784f, 0.876393f,
+0.885352f, 0.893698f, 0.901468f, 0.908698f, 0.915420f,
+0.921669f, 0.927473f, 0.932862f, 0.937863f, 0.942503f,
+0.946806f, 0.950795f, 0.954492f, 0.957917f, 0.961090f,
+0.964028f, 0.966747f, 0.969265f, 0.971594f, 0.973749f,
+0.975743f, 0.977587f, 0.979293f, 0.980869f, 0.982327f,
+0.983675f, 0.984921f, 0.986072f, 0.987136f, 0.988119f,
+0.989027f, 0.989867f, 0.990642f, 0.991359f, 0.992020f,
+0.992631f, 0.993196f, 0.993718f, 0.994199f, 0.994644f,
+0.995055f, 0.995434f, 0.995784f, 0.996108f, 0.996407f,
+0.996682f, 0.996937f, 0.997172f, 0.997389f, 0.997590f,
+0.997775f, 0.997946f, 0.998104f, 0.998249f, 0.998384f,
+0.998508f, 0.998623f, 0.998728f, 0.998826f, 0.998916f,
+0.999000f, 0.999076f, 0.999147f, 0.999213f, 0.999273f,
+0.999329f, 0.999381f, 0.999428f, 0.999472f, 0.999513f,
+0.999550f, 0.999585f, 0.999617f, 0.999646f, 0.999673f,
+0.999699f, 0.999722f, 0.999743f, 0.999763f, 0.999781f,
+0.999798f, 0.999813f, 0.999828f, 0.999841f, 0.999853f,
+0.999865f, 0.999875f, 0.999885f, 0.999893f, 0.999902f,
+0.999909f, 0.999916f, 0.999923f, 0.999929f, 0.999934f,
+0.999939f, 0.999944f, 0.999948f, 0.999952f, 0.999956f,
+0.999959f, 0.999962f, 0.999965f, 0.999968f, 0.999970f,
+0.999973f, 0.999975f, 0.999977f, 0.999978f, 0.999980f,
+0.999982f, 0.999983f, 0.999984f, 0.999986f, 0.999987f,
+0.999988f, 0.999989f, 0.999990f, 0.999990f, 0.999991f,
+0.999992f, 0.999992f, 0.999993f, 0.999994f, 0.999994f,
+0.999994f, 0.999995f, 0.999995f, 0.999996f, 0.999996f,
+0.999996f, 0.999997f, 0.999997f, 0.999997f, 0.999997f,
+0.999997f, 0.999998f, 0.999998f, 0.999998f, 0.999998f,
+0.999998f, 0.999998f, 0.999999f, 0.999999f, 0.999999f,
+0.999999f, 0.999999f, 0.999999f, 0.999999f, 0.999999f,
+0.999999f, 0.999999f, 0.999999f, 0.999999f, 0.999999f,
+1.000000f, 1.000000f, 1.000000f, 1.000000f, 1.000000f,
+1.000000f, 1.000000f, 1.000000f, 1.000000f, 1.000000f,
+1.000000f,
+};