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examples : move wav_writer from stream.cpp to common.h (#1317)
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* Allocate class on the stack instead of on the heap

* Add class wav_writer

* fix some minor issues

* fix some minor issues

* remove potential misleading API
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@bobqianic
bobqianic committed Oct 3, 2023
1 parent 4037705 commit 08fa348
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Showing 2 changed files with 105 additions and 57 deletions.
100 changes: 100 additions & 0 deletions examples/common.h
View file
Expand Up @@ -7,6 +7,8 @@
#include <vector>
#include <random>
#include <thread>
#include <ctime>
#include <fstream>

#define COMMON_SAMPLE_RATE 16000

Expand Down Expand Up @@ -139,6 +141,104 @@ bool read_wav(
std::vector<std::vector<float>> & pcmf32s,
bool stereo);

// Write PCM data into WAV audio file
class wav_writer {
private:
std::ofstream file;
uint32_t dataSize = 0;
std::string wav_filename;

bool write_header(const uint32_t sample_rate,
const uint16_t bits_per_sample,
const uint16_t channels) {

file.write("RIFF", 4);
file.write("\0\0\0\0", 4); // Placeholder for file size
file.write("WAVE", 4);
file.write("fmt ", 4);

const uint32_t sub_chunk_size = 16;
const uint16_t audio_format = 1; // PCM format
const uint32_t byte_rate = sample_rate * channels * bits_per_sample / 8;
const uint16_t block_align = channels * bits_per_sample / 8;

file.write(reinterpret_cast<const char *>(&sub_chunk_size), 4);
file.write(reinterpret_cast<const char *>(&audio_format), 2);
file.write(reinterpret_cast<const char *>(&channels), 2);
file.write(reinterpret_cast<const char *>(&sample_rate), 4);
file.write(reinterpret_cast<const char *>(&byte_rate), 4);
file.write(reinterpret_cast<const char *>(&block_align), 2);
file.write(reinterpret_cast<const char *>(&bits_per_sample), 2);
file.write("data", 4);
file.write("\0\0\0\0", 4); // Placeholder for data size

return true;
}

// It is assumed that PCM data is normalized to a range from -1 to 1
bool write_audio(const float * data, size_t length) {
for (size_t i = 0; i < length; ++i) {
const auto intSample = static_cast<const int16_t>(data[i] * 32767);
file.write(reinterpret_cast<const char *>(&intSample), sizeof(int16_t));
dataSize += sizeof(int16_t);
}
if (file.is_open()) {
file.seekp(4, std::ios::beg);
uint32_t fileSize = 36 + dataSize;
file.write(reinterpret_cast<char *>(&fileSize), 4);
file.seekp(40, std::ios::beg);
file.write(reinterpret_cast<char *>(&dataSize), 4);
file.seekp(0, std::ios::end);
}
return true;
}

bool open_wav(const std::string & filename) {
if (filename != wav_filename) {
if (file.is_open()) {
file.close();
}
}
if (!file.is_open()) {
file.open(filename, std::ios::binary);
wav_filename = filename;
dataSize = 0;
}
return file.is_open();
}

public:
bool open(const std::string & filename,
const uint32_t sample_rate,
const uint16_t bits_per_sample,
const uint16_t channels) {

if (open_wav(filename)) {
write_header(sample_rate, bits_per_sample, channels);
} else {
return false;
}

return true;
}

bool close() {
file.close();
return true;
}

bool write(const float * data, size_t length) {
return write_audio(data, length);
}

~wav_writer() {
if (file.is_open()) {
file.close();
}
}
};


// Apply a high-pass frequency filter to PCM audio
// Suppresses frequencies below cutoff Hz
void high_pass_filter(
Expand Down
62 changes: 5 additions & 57 deletions examples/stream/stream.cpp
View file
Expand Up @@ -2,7 +2,6 @@
//
// A very quick-n-dirty implementation serving mainly as a proof of concept.
//
#include <fstream>
#include "common-sdl.h"
#include "common.h"
#include "whisper.h"
Expand All @@ -13,60 +12,8 @@
#include <thread>
#include <vector>
#include <fstream>
#include <ctime>

class SimpleWavWriter {
private:
std::ofstream file;
int32_t dataSize = 0;

public:
SimpleWavWriter(const std::string &filename, int sampleRate, int bitsPerSample, int channels) {
file.open(filename, std::ios::binary);

file.write("RIFF", 4);
file.write("\0\0\0\0", 4); // Placeholder for file size
file.write("WAVE", 4);
file.write("fmt ", 4);

int32_t subChunkSize = 16;
int16_t audioFormat = 1; // PCM format
int32_t byteRate = sampleRate * channels * bitsPerSample / 8;
int16_t blockAlign = channels * bitsPerSample / 8;

file.write(reinterpret_cast<char *>(&subChunkSize), 4);
file.write(reinterpret_cast<char *>(&audioFormat), 2);
file.write(reinterpret_cast<char *>(&channels), 2);
file.write(reinterpret_cast<char *>(&sampleRate), 4);
file.write(reinterpret_cast<char *>(&byteRate), 4);
file.write(reinterpret_cast<char *>(&blockAlign), 2);
file.write(reinterpret_cast<char *>(&bitsPerSample), 2);
file.write("data", 4);
file.write("\0\0\0\0", 4); // Placeholder for data size
}

void writeData(const float *data, size_t length) {
for (size_t i = 0; i < length; ++i) {
int16_t intSample = static_cast<int16_t>(data[i] * 32767);
file.write(reinterpret_cast<char *>(&intSample), sizeof(int16_t));
dataSize += sizeof(int16_t);
}
if (file.is_open()) {
file.seekp(4, std::ios::beg);
int32_t fileSize = 36 + dataSize;
file.write(reinterpret_cast<char *>(&fileSize), 4);
file.seekp(40, std::ios::beg);
file.write(reinterpret_cast<char *>(&dataSize), 4);
file.seekp(0, std::ios::end);
}
}

~SimpleWavWriter() {
if (file.is_open()) {
file.close();
}
}
};
// 500 -> 00:05.000
// 6000 -> 01:00.000
std::string to_timestamp(int64_t t) {
Expand Down Expand Up @@ -266,16 +213,17 @@ int main(int argc, char ** argv) {
return 1;
}
}

wav_writer wavWriter;
// save wav file
SimpleWavWriter *wavWriter = nullptr;
if (params.save_audio) {
// Get current date/time for filename
time_t now = time(0);
char buffer[80];
strftime(buffer, sizeof(buffer), "%Y%m%d%H%M%S", localtime(&now));
std::string filename = std::string(buffer) + ".wav";

wavWriter = new SimpleWavWriter(filename, WHISPER_SAMPLE_RATE, 16, 1);
wavWriter.open(filename, WHISPER_SAMPLE_RATE, 16, 1);
}
printf("[Start speaking]\n");
fflush(stdout);
Expand All @@ -285,8 +233,8 @@ int main(int argc, char ** argv) {

// main audio loop
while (is_running) {
if (params.save_audio && wavWriter) {
wavWriter->writeData(pcmf32_new.data(), pcmf32_new.size());
if (params.save_audio) {
wavWriter.write(pcmf32_new.data(), pcmf32_new.size());
}
// handle Ctrl + C
is_running = sdl_poll_events();
Expand Down

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