63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
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//
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//本程序中的函数可以将PCM16LE双声道数据中左声道的音量降低一半。
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//
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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int pcm16le_halfvolumeleft(const char *file)
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{
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if (file == NULL) {
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printf("原始文件为空！\n");
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return 0;
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}
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FILE *fp = fopen(file, "rb+");
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if (fp == NULL) {
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printf("原始文件打开失败！\n");
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return 0;
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}
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FILE *fp1 = fopen("./output/output_halfleft.pcm", "wb+");
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if (fp1 == NULL) {
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printf("文件打开或创建失败！\n");
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return 0;
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}
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unsigned char buf[4] = {0};
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while(!feof(fp)) {
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//从文件中读取一次采样值，因为是16位的，所以需读取4个字节
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//左右声道采样值间隔存储
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//前两个字节为左声道采样值，后两个字节为右声道采样值
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fread(buf, 1, 4, fp);
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//将前两个字节(左声道采样值)强制转换为 short类型
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short *sample = (short *)buf;
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//将左声道采样值减半
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*sample = *sample / 2;
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//将减半的左声道采样值写入文件
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fwrite(sample, 1, 2, fp1);
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//将原始的右声道采样值写入文件
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fwrite(buf+2, 1, 2, fp1);
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}
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fclose(fp);
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fclose(fp1);
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return 1;
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}
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int main()
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{
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char file[] = "./mediadata/NocturneNo2inEflat_44.1k_s16le.pcm";
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if (pcm16le_halfvolumeleft(file)) {
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printf("操作成功！！！\n");
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} else {
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printf("操作失败！！！\n");
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}
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}
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