嵌入式linux播放视频 mplayer,嵌入式linux中mplayer播放视频编程实践

用android或是QT来开发视频播放程序相对来说比较简单，如果是在linux用纯C语言来进行开发，就显得比较麻烦，好在现在有很多开源项目能够帮助我们做什么事情，mplayer就是音视频播放开源项目中典型的例子。

首先需要去mplayer官方网站mplayer下载地址下载源代码，然后使用你的交叉编译工具进行编译，编译完成后会生成一个mplayer执行程序，在命令行执行mplayer就可以进行播放了。

但是，用c语言编程来实现mplayer的播放功能怎么实现呢，本文就来讲讲一个简单的mplayer播放器的实现。

一 、 创建一个管道，进行进程间通信

int fd_fifo;

int g_sock_pair[2]; //全双工管道标识符

int sock_stop_mplay[2];

char video_list[VIDEO_MAX_NUM][30];

void mplayer_init(void)

{

int sockID;

sockID=socketpair(AF_UNIX, SOCK_STREAM, 0, g_sock_pair);//建立全双工管道

if(sockID)

{

printf("the pipe is not contructed

");

exit(0);

}

else

{

IfPlay = FALSE;//设置标识符初始状态

IfStop = TRUE;

IfPause = FALSE;

IfQuit = TRUE;

video_over = FALSE;

}

if(pipe(sock_stop_mplay)<0)

{

printf("stop mplay pipe create error

");

return ;

}

}

二 、 获得视频播放目录的文件个数

int mplayer_get_video_name(void)

{

int i;

int num;

int total_num;

struct dirent **namelist;

char *filepath = "usr/video/";

memset(&video_list,0,sizeof(video_list));

num = scandir(filepath,&namelist,0,alphasort);

printf("the video num is: %d

",num);

if(num < 0)return -1;

if(num > VIDEO_MAX_NUM)

{

num = VIDEO_MAX_NUM;

}

for(i=0;id_name);

}

total_num = num-2;

return total_num;

printf("video name:%s

",video_list[0]);

}

三 、 mplayer播放器的实现

void video_play(void)

{

pid_t pid;

pid_t pid1;

FILE * fp;

char buf[1024];

int mark = 0; //播放标志

printf("the pid is %d

",getpid());

mplayer_init();

unlink("/usr/my_fifo"); //如果管道存在，则先删除

mkfifo("/usr/my_fifo",O_CREAT|0666);

perror("mkfifo");

fd_fifo=open("/usr/my_fifo",O_RDWR);

int pipe_fd[2]; //用于进程ID通信

int r_num;

char pipe_buf[100];

memset(pipe_buf,0,100);

if(pipe(pipe_fd)<0)

{

printf("pipe create error

");

return ;

}

pid = fork();

if(pid == 0)

{

char temp[100];

memset(temp,0,sizeof(temp));

printf("pid xxx= %d

",getpid());

sprintf(temp,"%d",getpid());

close(pipe_fd[0]);

if(write(pipe_fd[1],temp,strlen(temp))!=-1)

printf("child write success!

");

if((pid1=fork())==0)

{

//close(g_sock_pair[0]);

//dup2(g_sock_pair[1],1); //将子进程的标准输出重定向到管道的写端

int video_num = 0;

char *videoname;

int total_num;

char stop_cmd[20];

total_num = mplayer_get_video_name();

while(1)

{

if(mark)

{

video_num++;

printf("video_num = %d

",video_num);

if(video_num >= total_num)

{

video_num = 0;

printf("video_num more than total_num

");

}

}

videoname = video_list[video_num];

char videopath[50] = "/storage/unit_app/video/";

char sPlay[100]="mplayer -ao alsa -vo fbdev -vc on28190 -fs -slave -quiet -input file=/storage/my_fifo ";

strcat(videopath,videoname);

strcat(sPlay,videopath);

mplayer_background_pic();

memset(stop_cmd,0,20);

printf("begin play the video!

");

fp = popen(sPlay, "r");

if(fp ==NULL)

{

perror("popen");

exit(-1);

}

else

{

while(fgets(buf, sizeof(buf), fp))

{

printf("%s", buf);

}

printf("one video end play

");

pclose(fp);

mark = 1;

}

usleep(30000);

fcntl(sock_stop_mplay[0], F_SETFL, O_NONBLOCK);

read(sock_stop_mplay[0],stop_cmd,20);

if(strcmp(stop_cmd,"stop")==0)

{

mark = 0;

printf("rev the stop cmd

");

break;

}

printf("end the play pthread

");

}

exit(0);

}

if (waitpid(pid1, NULL, 0) != pid1)

{

fprintf(stderr,"Waitpid error!

");

exit(-1);

}

exit(0);

}

else if(pid >0)

{

close(pipe_fd[1]);

usleep(30000);

if((r_num=read(pipe_fd[0],pipe_buf,100))>0)

{

printf("%d numbers read from be pipe is %s

",r_num,pipe_buf);

childs_pid = atoi(&pipe_buf);

}

}

}

四、 mplayer的结束程序

void video_stop(void)

{

pid_t pid;

char cmd[100];

memset(cmd,0,100);

sprintf(cmd,"kill -9 %d",childs_pid);

char stop_cmd[20];

memset(stop_cmd,0,20);

sprintf(stop_cmd,"stop");

mplayer_send_cmd("quit

");

if(write(sock_stop_mplay[1],stop_cmd,strlen(stop_cmd))!=-1)

printf("write stop cmd success!

");

//clear_fb();

printf("kill childs_pid %d

",childs_pid);

system(cmd);

mplayer_del();

}

void mplayer_send_cmd(char *cmd)

{

write(fd_fifo,cmd,strlen(cmd));

}

void mplayer_del(void)

{

close(g_sock_pair[0]);//关闭管道

close(g_sock_pair[1]);

close(sock_stop_mplay[0]);

close(sock_stop_mplay[2]);

wait(NULL);//收集子进程信息

}

OK，只要实现上述代码，基本的mplayer播放器就可以实现了。