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.
71 lines
2.2 KiB
C++
71 lines
2.2 KiB
C++
/*
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AudioOutputSerialWAV
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Writes a mostly correct WAV file to the serial port
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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 "AudioOutputSerialWAV.h"
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bool AudioOutputSerialWAV::begin()
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{
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static uint8_t wavHeader[] = { // Hardcoded simple WAV header with 0xffffffff lengths all around
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0x52, 0x49, 0x46, 0x46, 0xff, 0xff, 0xff, 0xff, 0x57, 0x41, 0x56, 0x45,
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0x66, 0x6d, 0x74, 0x20, 0x10, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02, 0x00, 0x22, 0x56, 0x00, 0x00, 0x88, 0x58, 0x01, 0x00, 0x04, 0x00, 0x10, 0x00,
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0x64, 0x61, 0x74, 0x61, 0xff, 0xff, 0xff, 0xff };
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wavHeader[22] = channels & 0xff;
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wavHeader[23] = 0;
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wavHeader[24] = hertz & 0xff;
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wavHeader[25] = (hertz >> 8) & 0xff;
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wavHeader[26] = (hertz >> 16) & 0xff;
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wavHeader[27] = (hertz >> 24) & 0xff;
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int byteRate = hertz * bps * channels / 8;
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wavHeader[28] = byteRate & 0xff;
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wavHeader[29] = (byteRate >> 8) & 0xff;
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wavHeader[30] = (byteRate >> 16) & 0xff;
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wavHeader[31] = (byteRate >> 24) & 0xff;
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wavHeader[32] = channels * bps / 8;
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wavHeader[33] = 0;
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wavHeader[34] = bps;
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wavHeader[35] = 0;
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Serial.write(wavHeader, sizeof(wavHeader));
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return true;
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}
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bool AudioOutputSerialWAV::ConsumeSample(int16_t sample[2])
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{
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for (int i=0; i<channels; i++) {
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if (bps == 8) {
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uint8_t l = sample[i] & 0xff;
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Serial.write(l);
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} else {
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uint8_t l = sample[i] & 0xff;
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uint8_t h = (sample[i] >> 8) & 0xff;
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Serial.write(l);
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Serial.write(h);
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}
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}
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return true;
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}
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bool AudioOutputSerialWAV::stop()
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{
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Serial.print("\n\n\nEOF\n\n\n");
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return true;
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}
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