Following the path opened by FP6 IST PHOENIX project which was shown allowing an optimised allocation of resources for multimedia transmission over wired/wireless links in a joint source-channel coding approach for unicast transmissions, OPTIMIX project proposes to study innovative solutions enabling enhanced video streaming in a point to multi-point context for an IP based wireless heterogeneous system, based on cross layer adaptation of the whole transmission chain. Expected applications for such improvements are numerous in a time where users demand to have at their disposal on the move the same services they are already experiencing since a few years at home or in their offices. Typically, visiophony, video on demand on the move, access to streaming Internet websites, access to mobile personal television, location based services for educational, health, transport and environment purposes, virtual meetings or security professional applications are envisioned applications for the European end-user.