Complex sentence: Half of the stock of SMRTV at the time belonged to Radiotelevisione Italiana (RAI), the Italian broadcaster that withdrew from the contest in 1997, however San Marino RTV officially announced its participation at the Eurovision Song Contest 2008, held in Belgrade, Serbia.
Split into simpler sentences: Half of the stock of SMRTV at the time belonged to Radiotelevisione Italiana (RAI), the Italian broadcaster which withdrew from the contest in 1997. SMRTV, however, officially announced its participation at the Eurovision Song Contest 2008, held in Belgrade, Serbia.