kmeter_dsp.h

// SPDX-FileCopyrightText: © 2020-2021, 2024 Alexandros Theodotou <alex@zrythm.org>
// SPDX-License-Identifier: LicenseRef-ZrythmLicense OR GPL-2.0-or-later
/*
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 * ---
 *
 * Copyright (C) 2013 Robin Gareus <robin@gareus.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * ---
 */
 
#pragma once
 
#include <utility>
 
namespace zrythm::dsp
{

class KMeterDsp
{
public:
  void process (const float * p, int n);
 
  float read_f ();

  std::pair<float, float> read ();
 
  void reset ();

  void init (float samplerate);
 
private:
  float z1_{};   // filter state
  float z2_{};   // filter state
  float rms_{};  // max rms value since last read()
  float peak_{}; // max peak value since last read()
  int   cnt_{};  // digital peak hold counter
  int   fpp_{};  // frames per period
  float fall_{}; // peak fallback
  bool  flag_{}; // flag set by read(), resets _rms
 
  float omega_{}; // ballistics filter constant.
  int   hold_{};  // peak hold timeoute
  float fsamp_{}; // sample-rate
};
 
} // namespace zrythm::dsp