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