86 lines
2.8 KiB
C++
Executable File
86 lines
2.8 KiB
C++
Executable File
/*
|
|
AudioOutput
|
|
Base class of an audio output player
|
|
|
|
Copyright (C) 2017 Earle F. Philhower, III
|
|
|
|
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 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 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 _AUDIOOUTPUT_H
|
|
#define _AUDIOOUTPUT_H
|
|
|
|
#include <Arduino.h>
|
|
#include "AudioStatus.h"
|
|
|
|
class AudioOutput
|
|
{
|
|
public:
|
|
AudioOutput() { };
|
|
virtual ~AudioOutput() {};
|
|
virtual bool SetRate(int hz) { hertz = hz; return true; }
|
|
virtual bool SetBitsPerSample(int bits) { bps = bits; return true; }
|
|
virtual bool SetChannels(int chan) { channels = chan; return true; }
|
|
virtual bool SetGain(float f) { if (f>4.0) f = 4.0; if (f<0.0) f=0.0; gainF2P6 = (uint8_t)(f*(1<<6)); return true; }
|
|
virtual bool begin() { return false; };
|
|
typedef enum { LEFTCHANNEL=0, RIGHTCHANNEL=1 } SampleIndex;
|
|
virtual bool ConsumeSample(int16_t sample[2]) { (void)sample; return false; }
|
|
virtual uint16_t ConsumeSamples(int16_t *samples, uint16_t count)
|
|
{
|
|
for (uint16_t i=0; i<count; i++) {
|
|
if (!ConsumeSample(samples)) return i;
|
|
samples += 2;
|
|
}
|
|
return count;
|
|
}
|
|
virtual bool stop() { return false; }
|
|
virtual void flush() { return; }
|
|
virtual bool loop() { return true; }
|
|
|
|
public:
|
|
virtual bool RegisterMetadataCB(AudioStatus::metadataCBFn fn, void *data) { return cb.RegisterMetadataCB(fn, data); }
|
|
virtual bool RegisterStatusCB(AudioStatus::statusCBFn fn, void *data) { return cb.RegisterStatusCB(fn, data); }
|
|
|
|
protected:
|
|
void MakeSampleStereo16(int16_t sample[2]) {
|
|
// Mono to "stereo" conversion
|
|
if (channels == 1)
|
|
sample[RIGHTCHANNEL] = sample[LEFTCHANNEL];
|
|
if (bps == 8) {
|
|
// Upsample from unsigned 8 bits to signed 16 bits
|
|
sample[LEFTCHANNEL] = (((int16_t)(sample[LEFTCHANNEL]&0xff)) - 128) << 8;
|
|
sample[RIGHTCHANNEL] = (((int16_t)(sample[RIGHTCHANNEL]&0xff)) - 128) << 8;
|
|
}
|
|
};
|
|
|
|
inline int16_t Amplify(int16_t s) {
|
|
int32_t v = (s * gainF2P6)>>6;
|
|
if (v < -32767) return -32767;
|
|
else if (v > 32767) return 32767;
|
|
else return (int16_t)(v&0xffff);
|
|
}
|
|
|
|
protected:
|
|
uint16_t hertz;
|
|
uint8_t bps;
|
|
uint8_t channels;
|
|
uint8_t gainF2P6; // Fixed point 2.6
|
|
|
|
protected:
|
|
AudioStatus cb;
|
|
};
|
|
|
|
#endif
|
|
|