ftp AVOptions:

  -timeout           <int>        ED........ set timeout of socket I/O operations (from -1 to INT_MAX) (default -1)  超时

  -ftp-write-seekable <boolean>    E......... control seekability of connection during encoding (default false)

  -ftp-anonymous-password <string>     ED........ password for anonymous login. E-mail address should be used.匿名登陆的密码,一般是邮件。

  -ftp-user          <string>     ED........ user for FTP login. Overridden by whatever is in the URL.登陆用户名

  -ftp-password      <string>     ED........ password for FTP login. Overridden by whatever is in the URL.登陆密码