This letter proposes a reliable depth-image-based rendering (DIBR) technique, which can provide users with reliable 3D services even if contents contain unknown or inappropriate values in some parameters. For the reliable DIBR, this letter presents how to set rendering parameters such as far/near clipping plane, convergence distance, and scale factor by taking mobile display size into consideration. Various experiments show that the proposed method can be effectively employed for 3D services based on DIBR over terrestrial-digital multimedia broadcasting (T-DMB).