embdrv/lc3/Encoder/LongTermPostfilter.hpp

/*
 * LongTermPostfilter.hpp
 *
 * 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.
 */

#ifndef LONG_TERM_POSTFILER_H_
#define LONG_TERM_POSTFILER_H_

#include <cstdint>

#include "Datapoints.hpp"
#include "Lc3Config.hpp"

namespace Lc3Enc {

class LongTermPostfilter {
 public:
  LongTermPostfilter(const Lc3Config& lc3Config_, uint16_t nbits);
  virtual ~LongTermPostfilter();

  LongTermPostfilter& operator=(const LongTermPostfilter&);

  static uint8_t getP(uint16_t fs);
  static uint8_t getGainLtpfOn(uint16_t nbits, const Lc3Config& lc3Config);

  void registerDatapoints(DatapointContainer* datapoints_);

  void run(const int16_t* const x_s_, uint8_t near_nyquist_flag);

 private:
  void filterH50(double* xy);
  float compute_normvalue(const double* const x, uint8_t L, uint8_t T);
  uint8_t pitchDetection(float& normcorr);
  float interp(const float* R_12p8, uint8_t pitch_int_rel, int8_t d);
  void pitchLagParameter(uint8_t T_curr, uint8_t& pitch_int, int8_t& pitch_fr);
  float x_i_n_d(int16_t n, int8_t d);
  void activationBit(uint8_t pitch_int, uint8_t pitch_fr,
                     uint8_t near_nyquist_flag, float& nc, float& pitch);

 public:
  static const uint8_t Nmem12p8D = 232;
  static const uint8_t k_min = 17;
  static const uint8_t k_max = 114;

  const Lc3Config& lc3Config;
  const uint8_t len12p8;
  const uint8_t len6p4;
  const uint8_t D_LTPF;
  const uint8_t P;
  const uint8_t P_times_res_fac;
  const uint8_t gain_ltpf_on;

  uint16_t pitch_index;
  uint8_t pitch_present;
  uint8_t ltpf_active;
  uint8_t nbits_LTPF;

 private:
  uint8_t T_prev;
  float mem_pitch;
  uint8_t mem_ltpf_active;
  float mem_nc;
  float mem_mem_nc;
  double* x_s_extended;
  double* x_tilde_12p8D_extended;
  double h50_mem[2];
  double x_6p4_extended[64 + k_max];

  DatapointContainer* datapoints;
};

}  // namespace Lc3Enc

#endif  // LONG_TERM_POSTFILER_H_