李老师，您好，我在ubuntu 16.04下开发，代码如下：
int ret;
AVFormatContext *frmt_ctx;
char *devicename = “:0”; //[[video device]:[audio device]]
AVDictionary *options = NULL;

char errors[1024];

printf("start ffmpeg\n");

//register audio device
avdevice_register_all();
printf("register is success\n");

//get format
AVInputFormat *iformat = av_find_input_format("alsa");
printf("find alsa success\n");

//open device,第一个参数是双指针
if((ret = avformat_open_input(&frmt_ctx,devicename,iformat,&options)) < 0)
{
    av_strerror(ret,errors,1024);
    printf(stderr,"Failed to open audio device : [%d]%s\n",ret,errors);
    return -1;
}

程序执行到：avformat_open_input，出现：段错误（内存已转储）。不知道如何解决？