Wyner-Ziv video coding has become one of the hottest research topics in the video coding community due to the conceptual, theoretical and functional novelties it brings. Among the many practical architectures already available, feedback channel-based with channel coding, e.g. LDPC and turbo codes, solutions are rather popular. These solutions rely on decoder motion estimation based on periodic Intra coded key frames, setting the so-called GOP size, very much like in conventional video coding. This paper targets the ratedistortion and complexity performance study of this type of Wyner-Ziv coding solution as a function of the GOP size, considering both LPDC and turbo codes.