| Digital video service has gained people's attention greatly, with the prevalence of broadband, and the development of multimedia processing technology. There are many real-time multimedia applications, such as videoconference systems, video monitor systems, HDTV etc. Although network environment has been progressing a lot, the bandwidth resource is still limited as far as the fast growth of multimedia applications is concerned. In March 2003, the Joint Video Team (JVT) composed by two expert teams published the final draft of this compressed auto video standard, which is called H.264 agreement of ITU-T, or the advanced part of auto video coding of MPEG-4 of ISO/IEC. H.264/AVC becomes the new standard of video-compression which can provide higher compressibility and more friendly net interface.For the enhancement of the coding effciencies, the new standard adopts new tools such as multiple reference pictures, variable block-size in motion prediction, quarter-pixel accuracy for motion vector, short word-length integer transform, context-adaptive entropy coding and loop filter deblocking. Motion estimation & compensation is critical but computationally expensive for H.264/AVC if full search is used, so it is proposed fast motion estimation algorithm.We propose an improved and simplified fast motion estimation scheme to further speed up the encoding process, by studying the existing rapid motion estimation algorithms. We also analyze the scheme how to choice the reference frames and mode and the threshold of early termination, etc. in order to make good use of our fast motion estimation scheme. It puts forward the hardware structure in the chapter 4. The result shows that the proposed accelerator could reduce much motion estimation time. |
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