| Author: | Chiu, Man-yau |
| Title: | Fast motion estimation techniques and algorithms for H.264/AVC video compression |
| Degree: | Eng.D. |
| Year: | 2011 |
| Subject: | Video compression Digital video Algorithms Hong Kong Polytechnic University -- Dissertations |
| Department: | Faculty of Engineering |
| Pages: | xiv, 152 p. : ill. ; 30 cm. |
| Language: | English |
| Abstract: | Motion estimation is one of the most computational-intensive tasks in video compression. In order to reduce the amount of computation, various fast motion estimation algorithms have been developed. These fast algorithms can be classified into two groups. One is the lossy motion-estimation approach, which may have some degradation of predicted images, and the other is lossless, which means that the quality of the predicted images is exactly the same as those obtained by the conventional full search algorithm. The partial distortion search and successive elimination algorithm are two well-known techniques belonging to the second kind of approach. These two algorithms use different checking criteria to eliminate as much redundant computations as possible. Actually, the working principles of these methods are independent to each others and it is possible to apply them sequentially in order to achieve larger saving in computation. Hence, we propose a new fast full-search motion estimation algorithm which can exploit fully the advantages of adaptive partial distortion search and successive elimination algorithm. Experimental results show that this proposed algorithm has an average speed-up of 21.59 as compared with the full search algorithm in terms of computational efficiency. This result is much better than the method simply combining both partial distortion search and successive elimination algorithm, which has an average computational speed-up of only 10.60. For a practical realization using a PC, the average execution time speed-up for our algorithm is 10.33, which is also the best performance among all algorithms tested. H.264/AVC is the latest video coding standard, which is able to achieve higher compression efficiency compared to MPEG-2 at the expense of higher computational requirement. In this thesis, we describe initially how to adapt the conventional successive elimination algorithm (SEA) and multi-level SEA (MSEA) for variable block size multiple reference frames motion estimation. We then propose some new techniques, including the reuse of SEA/MSEA boundary values, to further speed up these motion estimation algorithms. Lastly, we propose a new fast full search algorithm which can effectively combine the SEA and partial distortion search for variable block size multiple reference frames motion estimation. Experimental results show that this proposed algorithm is faster than all fast full-search algorithms available in the literature; in particular, it can achieve an average operational speed-up of 2.28 and 1.91 faster than that of SAD reuse and an average execution time speed-up of 1.72 and 1.50 faster than that of SAD reuse, for QCIF and CIF video sequences respectively. Lastly, we propose a computationally-scalable motion estimation algorithm in which the number of operations required to code a video frame can be dynamically controlled. Unlike fast lossy search algorithms, the proposed algorithm can adaptively adjust its search strategy according to the imposed computational constraint and this algorithm can be used by consumer devices to realize real-time computational budget control for video compression. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b24453304.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 1.68 MB | Adobe PDF | View/Open |
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