mirror of
https://github.com/earlephilhower/libmad-8266.git
synced 2026-03-13 09:31:41 +08:00
dfcbff04e4
LIBMAD needs lots of memory for constants and internal variables, with both heap and stack really tight. Move all constants I can into PROGMEM, disable Layer-I and Layer-II decoders, move some things from the stack to heap, change some structures from char/short to ints to allow for PROGMEM easy access, and finally add a simple testbed. Tested with Newcleus' Jam On It, has 3K heap free. Needs memory optimization as well.
93 lines
2.2 KiB
C++
93 lines
2.2 KiB
C++
/*
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AudioOutputI2SDAC
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Audio player for an I2S connected DAC, 16bps
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Copyright (C) 2017 Earle F. Philhower, III
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <Arduino.h>
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#include <i2s.h>
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#include "AudioOutputI2SDAC.h"
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bool AudioOutputI2SDAC::i2sOn = false;
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AudioOutputI2SDAC::AudioOutputI2SDAC()
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{
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if (!i2sOn) i2s_begin();
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i2sOn = true;
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}
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AudioOutputI2SDAC::~AudioOutputI2SDAC()
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{
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if (i2sOn) i2s_end();
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i2sOn = false;
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}
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bool AudioOutputI2SDAC::SetRate(int hz)
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{
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// TODO - have a list of allowable rates from constructor, check them
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this->hertz = hz;
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i2s_set_rate(hz);
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return true;
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}
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bool AudioOutputI2SDAC::SetBitsPerSample(int bits)
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{
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if ( (bits != 16) && (bits != 8) ) return false;
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this->bps = bits;
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return true;
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}
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bool AudioOutputI2SDAC::SetChannels(int channels)
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{
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if ( (channels < 1) || (channels > 2) ) return false;
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this->channels = channels;
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return true;
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}
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bool AudioOutputI2SDAC::SetOutputModeMono(bool mono)
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{
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this->mono = mono;
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return true;
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}
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bool AudioOutputI2SDAC::begin()
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{
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// Nothing to do here, i2s will start once data comes in
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return true;
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}
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bool AudioOutputI2SDAC::ConsumeSample(int16_t sample[2])
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{
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MakeSampleStereo16( sample );
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if (this->mono) {
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// Average the two samples and overwrite
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uint32_t ttl = sample[LEFTCHANNEL] + sample[RIGHTCHANNEL];
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sample[LEFTCHANNEL] = sample[RIGHTCHANNEL] = (ttl>>1) & 0xffff;
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}
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uint32_t s32 = ((sample[RIGHTCHANNEL])<<16) | (sample[LEFTCHANNEL] & 0xffff);
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return i2s_write_sample_nb(s32); // If we can't store it, return false. OTW true
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}
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bool AudioOutputI2SDAC::stop()
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{
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// Nothing to do here. Maybe mute control if DAC doesn't do it for you
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return true;
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}
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