ft8_lib/common/wave.cpp

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2018-11-02 20:03:28 +08:00
#include "wave.h"
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <stdint.h>
// Save signal in floating point format (-1 .. +1) as a WAVE file using 16-bit signed integers.
void save_wav(const float *signal, int num_samples, int sample_rate, const char *path) {
char subChunk1ID[4] = {'f', 'm', 't', ' '};
uint32_t subChunk1Size = 16; // 16 for PCM
uint16_t audioFormat = 1; // PCM = 1
uint16_t numChannels = 1;
uint16_t bitsPerSample = 16;
uint32_t sampleRate = sample_rate;
uint16_t blockAlign = numChannels * bitsPerSample / 8;
uint32_t byteRate = sampleRate * blockAlign;
char subChunk2ID[4] = {'d', 'a', 't', 'a'};
uint32_t subChunk2Size = num_samples * blockAlign;
char chunkID[4] = {'R', 'I', 'F', 'F'};
uint32_t chunkSize = 4 + (8 + subChunk1Size) + (8 + subChunk2Size);
char format[4] = {'W', 'A', 'V', 'E'};
int16_t *raw_data = (int16_t *)malloc(num_samples * blockAlign);
for (int i = 0; i < num_samples; i++) {
float x = signal[i];
if (x > 1.0) x = 1.0;
else if (x < -1.0) x = -1.0;
raw_data[i] = int(0.5 + (x * 32767.0));
}
FILE *f = fopen(path, "wb");
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// NOTE: works only on little-endian architecture
fwrite(chunkID, sizeof(chunkID), 1, f);
fwrite(&chunkSize, sizeof(chunkSize), 1, f);
fwrite(format, sizeof(format), 1, f);
fwrite(subChunk1ID, sizeof(subChunk1ID), 1, f);
fwrite(&subChunk1Size, sizeof(subChunk1Size), 1, f);
fwrite(&audioFormat, sizeof(audioFormat), 1, f);
fwrite(&numChannels, sizeof(numChannels), 1, f);
fwrite(&sampleRate, sizeof(sampleRate), 1, f);
fwrite(&byteRate, sizeof(byteRate), 1, f);
fwrite(&blockAlign, sizeof(blockAlign), 1, f);
fwrite(&bitsPerSample, sizeof(bitsPerSample), 1, f);
fwrite(subChunk2ID, sizeof(subChunk2ID), 1, f);
fwrite(&subChunk2Size, sizeof(subChunk2Size), 1, f);
fwrite(raw_data, blockAlign, num_samples, f);
fclose(f);
free(raw_data);
}
// Load signal in floating point format (-1 .. +1) as a WAVE file using 16-bit signed integers.
int load_wav(float *signal, int &num_samples, int &sample_rate, const char *path) {
char subChunk1ID[4]; // = {'f', 'm', 't', ' '};
uint32_t subChunk1Size; // = 16; // 16 for PCM
uint16_t audioFormat; // = 1; // PCM = 1
uint16_t numChannels; // = 1;
uint16_t bitsPerSample; // = 16;
uint32_t sampleRate;
uint16_t blockAlign; // = numChannels * bitsPerSample / 8;
uint32_t byteRate; // = sampleRate * blockAlign;
char subChunk2ID[4]; // = {'d', 'a', 't', 'a'};
uint32_t subChunk2Size; // = num_samples * blockAlign;
char chunkID[4]; // = {'R', 'I', 'F', 'F'};
uint32_t chunkSize; // = 4 + (8 + subChunk1Size) + (8 + subChunk2Size);
char format[4]; // = {'W', 'A', 'V', 'E'};
FILE *f = fopen(path, "rb");
// NOTE: works only on little-endian architecture
fread((void *)chunkID, sizeof(chunkID), 1, f);
fread((void *)&chunkSize, sizeof(chunkSize), 1, f);
fread((void *)format, sizeof(format), 1, f);
fread((void *)subChunk1ID, sizeof(subChunk1ID), 1, f);
fread((void *)&subChunk1Size, sizeof(subChunk1Size), 1, f);
if (subChunk1Size != 16) return -1;
fread((void *)&audioFormat, sizeof(audioFormat), 1, f);
fread((void *)&numChannels, sizeof(numChannels), 1, f);
fread((void *)&sampleRate, sizeof(sampleRate), 1, f);
fread((void *)&byteRate, sizeof(byteRate), 1, f);
fread((void *)&blockAlign, sizeof(blockAlign), 1, f);
fread((void *)&bitsPerSample, sizeof(bitsPerSample), 1, f);
if (audioFormat != 1 || numChannels != 1 || bitsPerSample != 16) return -1;
fread((void *)subChunk2ID, sizeof(subChunk2ID), 1, f);
fread((void *)&subChunk2Size, sizeof(subChunk2Size), 1, f);
if (subChunk2Size / blockAlign > num_samples) return -2;
num_samples = subChunk2Size / blockAlign;
sample_rate = sampleRate;
int16_t *raw_data = (int16_t *)malloc(num_samples * blockAlign);
fread((void *)raw_data, blockAlign, num_samples, f);
for (int i = 0; i < num_samples; i++) {
signal[i] = raw_data[i] / 32768.0f;
}
free(raw_data);
fclose(f);
return 0;
}