let f = File.file_open Sys.argv.(1);;
let s = File.to_stream f 0;;
let ps = Page.to_rawPageStream s;;

let id = Types.int64_to_oogg32 (Int64.of_string Sys.argv.(2));;

let g = File.file_open ~writable:true Sys.argv.(3);;
let ostream = File.to_output_stream g 0;;
Page.write_rawPageStream ostream (MediaStream.filter ps [id])