Files
jack-looper/wav_io.c
2026-05-04 12:14:15 +00:00

256 lines
8.2 KiB
C

#include "wav_io.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <pthread.h>
static pthread_mutex_t wav_io_mutex = PTHREAD_MUTEX_INITIALIZER;
// WAV file header structures (little-endian)
typedef struct {
char chunkID[4]; // "RIFF"
uint32_t chunkSize; // file size - 8
char format[4]; // "WAVE"
} WAVHeader;
typedef struct {
char subchunk1ID[4]; // "fmt "
uint32_t subchunk1Size; // 16 for PCM
uint16_t audioFormat; // 1 = PCM, 3 = IEEE float
uint16_t numChannels;
uint32_t sampleRate;
uint32_t byteRate;
uint16_t blockAlign;
uint16_t bitsPerSample;
} FMTSubchunk;
typedef struct {
char subchunk2ID[4]; // "data"
uint32_t subchunk2Size;
} DataSubchunk;
static void write_le16(FILE *f, uint16_t v) {
unsigned char buf[2];
buf[0] = v & 0xFF;
buf[1] = (v >> 8) & 0xFF;
fwrite(buf, 1, 2, f);
}
static void write_le32(FILE *f, uint32_t v) {
unsigned char buf[4];
buf[0] = v & 0xFF;
buf[1] = (v >> 8) & 0xFF;
buf[2] = (v >> 16) & 0xFF;
buf[3] = (v >> 24) & 0xFF;
fwrite(buf, 1, 4, f);
}
static uint16_t read_le16(const unsigned char *buf) {
return (uint16_t)buf[0] | ((uint16_t)buf[1] << 8);
}
static uint32_t read_le32(const unsigned char *buf) {
return (uint32_t)buf[0] | ((uint32_t)buf[1] << 8) |
((uint32_t)buf[2] << 16) | ((uint32_t)buf[3] << 24);
}
int save_wav_float(const char *filename, const float *buffer, size_t num_samples, unsigned int sample_rate) {
if (!filename || !buffer || num_samples == 0) return -1;
pthread_mutex_lock(&wav_io_mutex);
FILE *f = fopen(filename, "wb");
if (!f) {
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
// Calculate sizes
uint32_t data_size = (uint32_t)(num_samples * sizeof(float));
uint32_t chunk_size = 36 + data_size;
// Write RIFF header
fwrite("RIFF", 1, 4, f);
write_le32(f, chunk_size);
fwrite("WAVE", 1, 4, f);
// Write fmt subchunk
fwrite("fmt ", 1, 4, f);
write_le32(f, 16); // subchunk1Size
write_le16(f, 3); // audioFormat = IEEE float
write_le16(f, 1); // numChannels = mono
write_le32(f, sample_rate);
write_le32(f, sample_rate * sizeof(float)); // byteRate
write_le16(f, sizeof(float)); // blockAlign
write_le16(f, 32); // bitsPerSample
// Write data subchunk
fwrite("data", 1, 4, f);
write_le32(f, data_size);
// Write samples
fwrite(buffer, sizeof(float), num_samples, f);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return 0;
}
int load_wav_float(const char *filename, float **buffer, size_t *num_samples, unsigned int *sample_rate) {
if (!filename || !buffer || !num_samples || !sample_rate) return -1;
pthread_mutex_lock(&wav_io_mutex);
FILE *f = fopen(filename, "rb");
if (!f) {
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
// Read RIFF header
unsigned char header[12];
if (fread(header, 1, 12, f) != 12) {
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
if (memcmp(header, "RIFF", 4) != 0 || memcmp(header + 8, "WAVE", 4) != 0) {
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
// Read chunks until we find fmt and data
uint16_t audio_format = 0;
uint16_t num_channels = 0;
uint32_t sample_rate_val = 0;
uint16_t bits_per_sample = 0;
uint32_t data_size = 0;
float *data_buffer = NULL;
while (1) {
unsigned char chunk_header[8];
if (fread(chunk_header, 1, 8, f) != 8) break;
uint32_t chunk_size = read_le32(chunk_header + 4);
if (memcmp(chunk_header, "fmt ", 4) == 0) {
unsigned char fmt_data[16];
if (chunk_size < 16) {
fseek(f, chunk_size, SEEK_CUR);
continue;
}
if (fread(fmt_data, 1, 16, f) != 16) break;
audio_format = read_le16(fmt_data);
num_channels = read_le16(fmt_data + 2);
sample_rate_val = read_le32(fmt_data + 4);
bits_per_sample = read_le16(fmt_data + 14);
// Skip any extra fmt data
if (chunk_size > 16) fseek(f, chunk_size - 16, SEEK_CUR);
} else if (memcmp(chunk_header, "data", 4) == 0) {
data_size = chunk_size;
// Allocate buffer
size_t num_frames = data_size / (bits_per_sample / 8) / num_channels;
data_buffer = (float *)calloc(num_frames, sizeof(float));
if (!data_buffer) {
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
if (audio_format == 3 && bits_per_sample == 32) {
// IEEE float
size_t read_size = num_frames * num_channels * sizeof(float);
if (read_size > data_size) read_size = data_size;
float *temp = (float *)malloc(read_size);
if (!temp) {
free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
if (fread(temp, 1, read_size, f) != read_size) {
free(temp);
free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
// Mix to mono if stereo
if (num_channels == 1) {
memcpy(data_buffer, temp, num_frames * sizeof(float));
} else {
for (size_t i = 0; i < num_frames; i++) {
float sum = 0.0f;
for (uint16_t ch = 0; ch < num_channels; ch++) {
sum += temp[i * num_channels + ch];
}
data_buffer[i] = sum / num_channels;
}
}
free(temp);
} else if (audio_format == 1 && bits_per_sample == 16) {
// 16-bit PCM
size_t read_size = num_frames * num_channels * sizeof(int16_t);
if (read_size > data_size) read_size = data_size;
int16_t *temp = (int16_t *)malloc(read_size);
if (!temp) {
free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
if (fread(temp, 1, read_size, f) != read_size) {
free(temp);
free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
// Convert to float and mix to mono
if (num_channels == 1) {
for (size_t i = 0; i < num_frames; i++) {
data_buffer[i] = (float)temp[i] / 32768.0f;
}
} else {
for (size_t i = 0; i < num_frames; i++) {
float sum = 0.0f;
for (uint16_t ch = 0; ch < num_channels; ch++) {
sum += (float)temp[i * num_channels + ch] / 32768.0f;
}
data_buffer[i] = sum / num_channels;
}
}
free(temp);
} else {
// Unsupported format
free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}
*buffer = data_buffer;
*num_samples = num_frames;
*sample_rate = sample_rate_val;
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return 0;
} else {
// Skip unknown chunk
fseek(f, chunk_size, SEEK_CUR);
}
}
// If we get here, we didn't find data
if (data_buffer) free(data_buffer);
fclose(f);
pthread_mutex_unlock(&wav_io_mutex);
return -1;
}