sid,
i would suggest for a minute that you take a step back and listen to the advice that is being told by the users above as they are trying to help and what they have said is correct. otherwise, you may begin to frustrate the people trying to help here.
1. there is ZERO chance of using a headphone OUTPUT as an INPUT. generally all inputs can not be used as outputs and all outputs can not be used as inputs. the only exceptions are hdmi (arc) and on some soundcards which are wired to allow for port swapping.
2. a cd/dvd input sounds to me like an aux input. it sounds like either 3.5mm or rca red+white which would be what you are looking for.
3. splitters do not work that way. adding a splitter would only duplicate the headphone...