Uploading Files via the Aras RESTful API

Very Informative article, but at the moment I am trying to use the Restful  API to down load file which have been uploaded, most of the articles seem to be about uploading and not down loading. The documentation does not talk about transaction method for downloading only up loading. Some of the we are playing are very in the order of 500MB so I expect totake quite a while. The other question is about the encoding methods which are used you point to W3 page which talks about HTML URL Encode but it does not give it a name like base64 encoding. I have downloaded plain text file with no problems, but pdf file have binary character and these cause a problem. Any suggestion as to type of encoding/decoding I should be looking for, it would be nice  down loaded from the body test was a json { "encoded": "base64", "data" : "asdfghjk ..etc"