In this paper, we propose an improved adaptive interpolation filter method for improving coding efficiency in H.264/
AVC. Although the conventional cost functions have showed a good performance in terms of rate and distortion, it still
leaves room for improvement. To improve coding efficiency, we introduce a new cost function which considers the bit
rates and distortion for coding the macroblock. The best filter is adaptively selected to minimize the proposed cost
function. Experimental results show that the adaptive interpolation filter with the proposed cost function significantly
improves the coding efficiency compared to ones using conventional cost function. It leads to about a 5.62% (1 reference
frame) and 5.14% (5 reference frames) bit rate reduction on average compared to H.264/AVC, respectively.
We propose an advanced motion-compensated prediction method for improving the coding efficiency in H.264/AVC. Nine separable two-dimensional interpolation filters are applied to precise compensation for motion in various directions. A new optimal cost function, which considers the bit rate and distortion for coding the macroblock, is also proposed. The filter is adaptively selected per macroblock to minimize the proposed cost function. Also, an algorithm for reducing the overhead of transmitting the filter coefficients is described. In experimental results on the various standard QCIF/CIF test video sequences, the proposed method shows improvement in coding efficiency over conventional methods. This leads to approximately a 7.30% (for one reference frame) and 4.46% (for five reference frames) bit-rate reduction on average, compared to H.264/AVC.