He/she talks about open sourcing and porting ratDVD as can be seen below (I've slightly edited the quote):
How about Linux, Mac? Will you do a port?
I would be interested into doing a Linux port. However, since I am an ignorant Windows nerd I have no idea how it can be done. What I will do is releasing more and more components as open source over time and so people, who know what they are doing can work on it.
One thing I do know is that porting the UI is probably not hard since it is Delphi and can be recompiled with Kylix relatively simple. The bigger problem is that the underlying architecture is based on DirectShow filters and so probably needs a lot of changes.
Well, again I have to say it sounds intriguing but Mac is totally unknown to me. But hey, if there are people who are interested in it and I get a little more time, why not â€“ although I fear this will be more a rewrite than a port.
If he/she is wanting to open source rDVD then I'd suggest using the GPL and posting it as a project on SourceForge (http://sourceforge.net/); unfortunately Kylix is no longer supported -- by that I mean that Borland stopped Kylix a few years ago...yes I know it's basically the Linux version of Delphi which in itself is actually just Pascal) -- so for Linux it may or may not need a rewrite like he/she talks about doing for a Mac version.