工程中标查询网站营销心得体会感悟300字

目录

FFmpeg日志系统

FFmpeg文件与目录操作

FFmpeg文件的删除与重命名

FFmpeg操作目录及list的实现

操作目录重要函数

操作目录重要结构体

---

FFmpeg日志系统

下面看一个简单的 demo。

#include <stdio.h>
#include <libavutil/log.h>int main(int argc,char* argv[])
{av_log_set_level(AV_LOG_DEBUG);av_log(NULL,AV_LOG_INFO,"Hello World!,%s\n","aaa");return 0;
}

编译运行，结果如下：

wj@ubuntu:~/FFmpeg$ gcc -g -o ffmpeg_log ffmpeg_log.c -lavutil
wj@ubuntu:~/FFmpeg$ ./ffmpeg_log 
Hello World!,aaa

FFmpeg文件与目录操作

FFmpeg文件的删除与重命名

1. 文件删除函数：avpriv_io_delete()
2. 文件重命名：avpriv_io_move()

来看一个 demo

#include <stdio.h>
#include <libavformat/avformat.h>int main(int argc,char* argv[])
{int ret = 0;ret = avpriv_io_move("111.txt","222.txt");if(ret < 0){av_log(NULL,AV_LOG_ERROR,"Failed to rename\n");}av_log(NULL,AV_LOG_INFO,"Success to rename\n");//delete urlret = avpriv_io_delete("./mytestfile.txt");if(ret<0){av_log(NULL,AV_LOG_ERROR,"Failed to delete file mytestfile.txt\n");return -1;}av_log(NULL,"Success to delete mytestfile.txt");return 0;
}

sudo apt-get install libavformat-dev

wj@ubuntu:~/FFmpeg$ gcc -g -o ffmpeg_del ffmpeg_file.c -lavformat -lavutil
ffmpeg_file.c: In function ‘main’:
ffmpeg_file.c:8:11: warning: implicit declaration of function ‘avpriv_io_move’ [-Wimplicit-function-declaration]8 |     ret = avpriv_io_move("111.txt","222.txt");|           ^~~~~~~~~~~~~~
ffmpeg_file.c:18:11: warning: implicit declaration of function ‘avpriv_io_delete’ [-Wimplicit-function-declaration]18 |     ret = avpriv_io_delete("./mytestfile.txt");|           ^~~~~~~~~~~~~~~~
wj@ubuntu:~/FFmpeg$ ./ffmpeg_del 
Success to rename
Failed to delete file mytestfile.txt

FFmpeg操作目录及list的实现

操作目录重要函数

1. avio_open_dir()
2. avio_read_dir()
3. avio_close_dir()

操作目录重要结构体

1. AVIODirContext     操作目录的上下文
2. AVIODirEntry         目录项。用于存放文件名，文件大小等信息。

实战：实现一个简单的 ls 命令

#include <stdio.h>
#include <libavformat/avformat.h>int main(int argc,char* argv[])
{int ret = 0;AVIODirContext* ctx = NULL;AVIODirEntry* entry=NULL;av_log_set_level(AV_LOG_INFO);ret = avio_open_dir(&ctx,"./",NULL);if(ret < 0){av_log(NULL,AV_LOG_ERROR,"Can not open dir:%s\n",av_err2str(ret));return -1;}while(1){ret = avio_read_dir(ctx,&entry);if(ret < 0){av_log(NULL,AV_LOG_ERROR,"can not dir:%s\n",av_err2str(ret));//return -1;goto __fail; //avoid memleak}if(!entry){break;}av_log(NULL,AV_LOG_INFO,"%12"PRId64" %s \n",entry->size,entry->name);avio_free_directory_entry(&entry);}__fail:avio_close_dir(&ctx);return 0;
}

编译运行，如下所示：

wj@ubuntu:~/FFmpeg$ gcc -g -o ffmpeg_ls ffmpeg_ls.c -lavformat -lavutil
wj@ubuntu:~/FFmpeg$ ./ffmpeg_ls 190 ffmpeg_log.c 127296 ffmpeg_log 0 222.txt 579 ffmpeg_file.c 4096 .vscode 848 ffmpeg_ls.c 20800 ffmpeg_ls 19776 ffmpeg_del