Memory Optimization of Motion Compensation in MPEG-2 to H.264 Transcoder

Motion compensation and estimation are the computation intensive tools in MPEG-2 to H.264 transcoder. Both MPEG-2 and H.264 standards adapt block based motion estimation. The block sizes of both the standards differs. The motion vector derivation is an important step in motion compensation. Motion vectors are recovered during VLC decoding of MPEG-2 decoder are reused in H.264 encoder. The H.264/AVC standard uses different block sizes. Data correlation logic is used to decide the computation of motion vectors in H.264 encoder. A contributory work is done in reducing the number of computations in transcoder by using data correlation of blocks. In the present approach, motion vectors reuse and data correlation in transcoder minimizes the number of computations by 38%. The data correlation facilitates relative motion computation between neighbouring frames that significantly improves the computational complexity. The proposed algorithm is tested for test vectors in QCIF 4:2:0 chroma format.