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FFmpegAndroid/app/src/main/cpp/pcm/pcm_process.cpp

93 lines
2.2 KiB

//
// 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);
}