What does the ORC SERDE do

[侯宗田]

Hello,everyone
   I know the json serde turn fields in a row to a json format, csv serde turn 
it to csv format with their serdeproperties. But I wonder what the orc serde 
does when I choose to stored as orc file format. And why is there still 
escaper, separator in orc serdeproperties. Also with RC Parquet. I think they 
are just about how to stored and compressed with their input and output format 
respectively, but I don’t know what their serde does, can anyone give some 
hint?