ax630c_alsa_fix_samplerate.c

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#pragma pack(push, 1)
typedef struct {
    char riff[4];            // "RIFF"
    uint32_t chunkSize;      // File size
    char wave[4];            // "WAVE"
    char fmt[4];             // "fmt "
    uint32_t subchunk1Size;  // PCM = 16
    uint16_t audioFormat;    // PCM = 1
    uint16_t numChannels;    // Number of channels
    uint32_t sampleRate;     // Sample rate
    uint32_t byteRate;       // Byte rate
    uint16_t blockAlign;     // Block alignment
    uint16_t bitsPerSample;  // Bits per sample
} WavHeader;
#pragma pack(pop)

int main() {
    FILE *inputFile = fopen("input.wav", "rb");
    if (!inputFile) {
        perror("Unable to open input file");
        return 1;
    }

    WavHeader header;
    fread(&header, sizeof(WavHeader), 1, inputFile);

    if (strncmp(header.riff, "RIFF", 4) != 0 || strncmp(header.wave, "WAVE", 4) != 0) {
        fprintf(stderr, "Not a valid WAV file\n");
        fclose(inputFile);
        return 1;
    }

    // Modify sample rate to 32000
    header.sampleRate = 32000;
    header.byteRate = header.sampleRate * header.numChannels * header.bitsPerSample / 8;

    FILE *outputFile = fopen("output.wav", "wb");
    if (!outputFile) {
        perror("Unable to open output file");
        fclose(inputFile);
        return 1;
    }

    // Write modified header
    fwrite(&header, sizeof(WavHeader), 1, outputFile);

    // Copy the remaining data from input file to output file
    char buffer[4096];
    size_t bytesRead;
    while ((bytesRead = fread(buffer, 1, sizeof(buffer), inputFile)) > 0) {
        fwrite(buffer, 1, bytesRead, outputFile);
    }

    fclose(inputFile);
    fclose(outputFile);

    // Print completion messages in English and Japanese
    printf("Sample rate modification completed, output saved to output.wav\n");

    return 0;
}