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sdrangel/sdrbase/audio/audiocompressor.h

51 lines
2.1 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2018 F4EXB //
// written by Edouard Griffiths //
// //
// 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 as version 3 of the License, 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 V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef SDRBASE_AUDIO_AUDIOCOMPRESSOR_H_
#define SDRBASE_AUDIO_AUDIOCOMPRESSOR_H_
#include <stdint.h>
#include "export.h"
class SDRBASE_API AudioCompressor
{
public:
AudioCompressor();
~AudioCompressor();
void fillLUT(); //!< 4 bands
void fillLUT2(); //!< 8 bands (default)
void fillALaw(); //!< A-law compression to 8 bits
void fillULaw(); //!< u-law compression to 8 bits
int16_t compress(int16_t sample);
int8_t compress8(int16_t sample);
private:
int8_t ALaw_Encode(int16_t number);
int8_t MuLaw_Encode(int16_t number);
int16_t m_lut[32768];
static const uint16_t ALAW_MAX;
static const uint16_t MULAW_MAX;
static const uint16_t MULAW_BIAS;
};
#endif /* SDRBASE_AUDIO_AUDIOCOMPRESSOR_H_ */