All-zero-AC block detection using energy preservation theorem for H.263 video coding

This paper present a technique used in H.263 video coding to detect all-zero-AC occurrence without performing the transformation and quantization process. It is developed based on the energy preservation theorem. When the total AC energy in the pre-transform domain is known, the occurrence of all-zero-AC is predictable by comparing the total AC energy with the quantization threshold Q². The evaluations indicate that its prediction efficiency and speed gain depends on motion activities, level of Q and also the relative overhead imposed by the shortcut itself. In conclusion, the proposed new algorithm is expected to be practical in all common environments (low bit rate) targeted by H.263 standards as no negative speed gain is observed during the evaluation for all range of QP (Q=2.5QP)