Abstract
A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264 with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. First, an early-stop technique is introduced to determine the 16×16-mode blocks, which take up about 70% of all the macroblocks; then, a bottom-up merging process is performed to determine the mode of rest non-early-stopped blocks; and then, we adopt half-pixel motion estimation to further refine the acquired predictive motion vectors. In order to obtain the predictive motion vectors for early-stop and merging processes, we propose a motion vector composition scheme, which can reuse the information in the input pre-encoded videos to handle the spatial resolution down-scaling. Experimental results showed that our algorithm is about four times faster than the Cascaded-Decoder-Encoder method and has negligible PSNR drop and little bit rate increase.
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Project supported by the National Natural Science Foundation of China (No. 60573176), the Key Technologies R & D Program of Zhejiang Province (Nos. 2005C23047 and 2004C11052), China
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Bu, Jj., Mo, Lj., Chen, C. et al. Fast mode decision algorithm for spatial resolutions down-scaling transcoding to H.264. J. Zhejiang Univ. - Sci. A 7 (Suppl 1), 70–75 (2006). https://doi.org/10.1631/jzus.2006.AS0070
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DOI: https://doi.org/10.1631/jzus.2006.AS0070