I've implemented the same thing in a Usenet/NZB streaming project a few years ago - it's actually trivial since the multi-part rars are uncompressed, so the raw

I've implemented the same thing in a Usenet/NZB streaming project a few years ago - it's actually trivial since the multi-part rars are uncompressed, so the raw bytes of inner-content are there ready to be read. Just have to handle RAR headers/trailers. Seeking worked too since Usenet posts were commonly made up of 700kb posts, so if a seek occurred, you prioritize retrieving the required posts where the user seeked to, to fill the media player buffer. Code has never been released for obvious reasons :)