New scalable three-stage motion estimation technique for mobile MPEG encoding
The paper presents a new scalable three-stage motion estimation technique, which includes processing of frames in display order and approximating motion vector fields using multiple references. Quality refinement is added as an optional stage. The complete system provides a flexible framework with a large scalability range in computational effort, resulting in different picture-quality levels or bitrates. Experiments show a scalable computational effort with a factor of 14, resulting in a global variation of 7 dB SNR in picture quality (with the "Stefan" sequence). In high-quality operation, the new method is comparable to a full-search motion estimation with a search window of 32/spl times/32 pixels (or even outperforms it). The innovation provides an excellent starting point for scalability in resource-constrained mobile system design (see Mietens, S. et al., IEEE Int. Conf. on Image Proc., ICIP 2001, vol.3, p.462-5, 2001).