//

// Created by xu fulong on 2022/8/5.

//

#include <cstdio>

#include <cerrno>

#include <cstdlib>

#include <cstring>

void pcm_raise_speed(char *input_path, char *output_path)

{

FILE *input = fopen(input_path, "rb+");

FILE *output = fopen(output_path, "wb+");

if (!input && !output) {

printf("open file fail, msg=%s\n", strerror(errno));

return;

}

int count = 0;

char *buf = (char*) malloc(sizeof(char) * 4);

while(!feof(input)) {

fread(buf, sizeof(char), 4, input);

if (count % 2 == 0) {

// L

fwrite(buf, sizeof(char), 2, output);

// R

fwrite(buf + 2, sizeof(char), 2, output);

}

count++;

}

free(buf);

fclose(output);

fclose(input);

}

void pcm_change_volume(char *input_path, char *output_path)

{

FILE *input = fopen(input_path, "rb+");

FILE *output = fopen(output_path, "wb+");

if (!input && !output) {

printf("open file fail, msg=%s\n", strerror(errno));

return;

}

int count = 0;

char *buf = (char*) malloc(sizeof(char) * 4);

while(!feof(input)) {

fread(buf, sizeof(char), 4, input);

short *left = (short*) buf;

*left /= 2;

short *right = (short*) (buf + 2);

*right /= 2;

// L

fwrite(left, sizeof(short), 1, output);

// R

fwrite(right, sizeof(short), 1, output);

count++;

}

printf("resample count=%d\n", count);

free(buf);

fclose(output);

fclose(input);

}

void pcm_split_channel(char *input_path, char *left_path, char *right_path)

{

FILE *input = fopen(input_path, "rb+");

FILE *left = fopen(left_path, "wb+");

FILE *right = fopen(right_path, "wb+");

if (!input && !left && !right) {

printf("open file fail, msg=%s\n", strerror(errno));

return;

}

int count = 0;

char *buf = (char*) malloc(sizeof(char) * 4);

while(!feof(input)) {

fread(buf, sizeof(char), 4, input);

// L

fwrite(buf, sizeof(char), 2, left);

// R

fwrite(buf+2, sizeof(char), 2, right);

count++;

}

printf("resample count=%d\n", count);

free(buf);

fclose(left);

fclose(right);

fclose(input);

}