[Video and Audio Data Processing] 截取部分PCM16LE单声道音频采样数据

0. 代码

extern "C"
{
#ifdef __cplusplus
#define __STDC_CONSTANT_MACROS

#endif

}
extern "C" {

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
}






/**
 * Cut a 16LE PCM single channel file.
 * @param url        Location of PCM file.
 * @param start_num  start point
 * @param dur_num    how much point to cut
 */
int simplest_pcm16le_cut_singlechannel(const char* url, int start_num, int dur_num) {
	FILE* fp = fopen(url, "rb+");
	FILE* fp1 = fopen("output_cut.pcm", "wb+");
	FILE* fp_stat = fopen("output_cut.txt", "wb+");

	unsigned char* sample = (unsigned char*)malloc(2);

	int cnt = 0;
	while (!feof(fp)) {
		fread(sample, 1, 2, fp);
		if (cnt > start_num && cnt <= (start_num + dur_num)) {
			fwrite(sample, 1, 2, fp1);

			short samplenum = sample[1];
			samplenum = samplenum * 256;
			//获取高8位的采样值
			samplenum = samplenum + sample[0];
			//获取整体的采样值

			fprintf(fp_stat, "%6d,", samplenum);
			//以%6d的格式，向输出流fp_stat写入samplenum的数据
			if (cnt % 10 == 0)
				fprintf(fp_stat, "\n", samplenum);
			//以\n的格式-换行，向输出流fp_stat写入samplenum的数据
		}
		cnt++;
	}

	free(sample);
	fclose(fp);
	fclose(fp1);
	fclose(fp_stat);
	return 0;
}




int main()
{
	simplest_pcm16le_cut_singlechannel("drum.pcm", 2360, 120);
	return 0;
}

音源获取：https://github.com/leixiaohua1020/simplest_mediadata_test

1. 运行效果

原始音频文件：

处理之后的截取的音频文件：

输出的 采样数据：

参考链接：

https://blog.youkuaiyun.com/leixiaohua1020/article/details/50534316