wave-writer.cc
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// sherpa-onnx/csrc/wave-writer.cc
//
// Copyright (c) 2023 Xiaomi Corporation
#include "sherpa-onnx/csrc/wave-writer.h"
#include <fstream>
#include <string>
#include <vector>
#include "sherpa-onnx/csrc/macros.h"
namespace sherpa_onnx {
namespace {
// see http://soundfile.sapp.org/doc/WaveFormat/
//
// Note: We assume little endian here
// TODO(fangjun): Support big endian
struct WaveHeader {
int32_t chunk_id;
int32_t chunk_size;
int32_t format;
int32_t subchunk1_id;
int32_t subchunk1_size;
int16_t audio_format;
int16_t num_channels;
int32_t sample_rate;
int32_t byte_rate;
int16_t block_align;
int16_t bits_per_sample;
int32_t subchunk2_id; // a tag of this chunk
int32_t subchunk2_size; // size of subchunk2
};
} // namespace
bool WriteWave(const std::string &filename, int32_t sampling_rate,
const float *samples, int32_t n) {
WaveHeader header{};
header.chunk_id = 0x46464952; // FFIR
header.format = 0x45564157; // EVAW
header.subchunk1_id = 0x20746d66; // "fmt "
header.subchunk1_size = 16; // 16 for PCM
header.audio_format = 1; // PCM =1
int32_t num_channels = 1;
int32_t bits_per_sample = 16; // int16_t
header.num_channels = num_channels;
header.sample_rate = sampling_rate;
header.byte_rate = sampling_rate * num_channels * bits_per_sample / 8;
header.block_align = num_channels * bits_per_sample / 8;
header.bits_per_sample = bits_per_sample;
header.subchunk2_id = 0x61746164; // atad
header.subchunk2_size = n * num_channels * bits_per_sample / 8;
header.chunk_size = 36 + header.subchunk2_size;
std::vector<int16_t> samples_int16(n);
for (int32_t i = 0; i != n; ++i) {
samples_int16[i] = samples[i] * 32676;
}
std::ofstream os(filename, std::ios::binary);
if (!os) {
SHERPA_ONNX_LOGE("Failed to create %s", filename.c_str());
return false;
}
os.write(reinterpret_cast<const char *>(&header), sizeof(header));
os.write(reinterpret_cast<const char *>(samples_int16.data()),
samples_int16.size() * sizeof(int16_t));
if (!os) {
SHERPA_ONNX_LOGE("Write %s failed", filename.c_str());
return false;
}
return true;
}
} // namespace sherpa_onnx