embdrv/lc3/Encoder/NoiseLevelEstimation.cpp

/*
 * NoiseLevelEstimation.cpp
 *
 * Copyright 2021 HIMSA II K/S - www.himsa.com. Represented by EHIMA -
 * www.ehima.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "NoiseLevelEstimation.hpp"

#include <algorithm>
#include <cmath>

namespace Lc3Enc {

NoiseLevelEstimation::NoiseLevelEstimation(const Lc3Config& lc3Config_)
    : lc3Config(lc3Config_), F_NF(0), datapoints(nullptr) {}

NoiseLevelEstimation::~NoiseLevelEstimation() {}

void NoiseLevelEstimation::run(const double* const X_f,
                               const int16_t* const X_q, uint8_t P_bw,
                               double gg) {
  const uint16_t bw_stop_table_10ms[5] = {80, 160, 240, 320, 400};
  const uint16_t bw_stop_table_7p5ms[5] = {60, 120, 180, 240, 300};
  const uint16_t bw_stop = (Lc3Config::FrameDuration::d10ms == lc3Config.N_ms)
                               ? bw_stop_table_10ms[P_bw]
                               : bw_stop_table_7p5ms[P_bw];
  uint16_t NF_start =
      (Lc3Config::FrameDuration::d10ms == lc3Config.N_ms) ? 24 : 18;
  uint16_t NF_width =
      (Lc3Config::FrameDuration::d10ms == lc3Config.N_ms) ? 3 : 2;

  double L_NF_numerator = 0;
  uint16_t L_NF_denominator = 0;
  for (uint16_t k = NF_start; (k < lc3Config.NE) && (k < bw_stop); k++) {
    bool I_NF_k = true;
    for (uint16_t i = k - NF_width; (i < bw_stop) && (i <= k + NF_width); i++) {
      if (X_q[i] != 0) {
        // -> I_NF[k] = 0;
        I_NF_k = false;
        break;
      }
    }
    if (I_NF_k) {
      // L_NF_numerator += fabs(X_f[k]);
      L_NF_numerator += (X_f[k] > 0) ? X_f[k] : -X_f[k];
      L_NF_denominator++;
    }
  }
  double L_NF = 0;
  if ((L_NF_denominator > 0) && (gg > 0)) {
    // L_NF_numerator /= gg;
    L_NF = L_NF_numerator / gg / L_NF_denominator;
  }

  double diff = 8 - 16 * L_NF;
  if (diff >= 0) {
    F_NF = std::min(static_cast<int>(diff + 0.5),
                    7);  // specification says rounding,
    // F_NF = std::min( static_cast<int>(ceil(diff)), 7 );  // but sometimes it
    // seems like the reference encoder computes ceil(.)
  } else {
    F_NF = 0;
  }

  if (nullptr != datapoints) {
    datapoints->log("L_NF", &L_NF, sizeof(L_NF));
    datapoints->log("L_NF_numerator", &L_NF_numerator, sizeof(L_NF_numerator));
    datapoints->log("L_NF_denominator", &L_NF_denominator,
                    sizeof(L_NF_denominator));
  }
}

void NoiseLevelEstimation::registerDatapoints(DatapointContainer* datapoints_) {
  datapoints = datapoints_;
  if (nullptr != datapoints) {
    datapoints->addDatapoint("F_NF", &F_NF, sizeof(F_NF));
  }
}

}  // namespace Lc3Enc