Video speed slow down in FMPEG

I am trying do bit slow video speed slow down which H264 format in fmpeg at android,When I run below code, it makes slowly and makes error.

String[] cmd3 = {"-i",h264_path,"-filter:v","setpts=1.25*PTS",h264_new_path};

     try {
         executeCommand(cmd3);
         } 
     catch(FFmpegCommandAlreadyRunningException e) {
         e.printStackTrace();
         }