This book constitutes the refereeed proceedings of the Third European Conference on Multimedia Applications, Services and Techniques, ECMAST '98, held in Berlin, Germany, in May 1998. The 40 revised full papers presented were carefully selected for inclusion in the book by the program committee. The topics covered include multimedia networks and protocols; coded representation of images, sound, and data; multimedia delivery on broadcast and telecom networks; servers and storage architechtures; advanced multimedia terminals and in house networks; multimedia services; Internet and multimedia scenario; and multimedia trials.