In order to enable real-time software-based video encoding, in this work we optimized the prediction stage of an H.264 video encoder, in the complexity sense. Thus, besides looking for the coding options which lead to the best coded representation in terms of rate and distortion (RD), we constrain to a complexity (C) budget. We present a complexity optimized framework (RDC-optimized) which allows for real-time video compression and that does not make use of frame-skipping to comply to the desired encoding speed. We developed our framework around an open source software implementation of the H.264/AVC, the the ×264 encoder. Results show that tight complexity control is attainable in practice, with very little loss in RD performance.