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Design And Implementation Of Discrete Cosine Transform

Posted on:2007-01-17Degree:MasterType:Thesis
Country:ChinaCandidate:C X ZhangFull Text:PDF
GTID:2178360182990410Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
Transform plays an essential role in conventional video coding standards based on hybrid coding technology. The highly correlated spatial signals are converted to much less correlated signals in transform domain by transform, thus facilitating further compression. The discrete cosine transform (DCT) is widely used in video coding standards because the DCT exhibits compression ability similar to the optimal Karhunen-Loeve transform (KLT) and at the same time the computational complexity is moderate.The fundamental and characteristic of the DCT is first analyzed and some commonly used fast alagorithms are introduced. Then the mismatch problem of the Inverse Discrete Cosine Transform (IDCT) and the fixed point 8x8 IDCT and DCT standard, which is being developed by MPEG working group with the purpose of reducing the drift, are described. Some existing IDCT implementation methods, such as lifting structure based and AAN structure based, and their respective merits and drawbacks, are also studied.Based on the understanding of the existing methods, two kinds of the IDCT implementation methods using the LLM structure are proposed and specifc implementation schemes on different platforms are also examined. The performance and complexity of the proposed methods are analyzed in detail. Comparison with other existing methods is also made.Further, the drift test conditions and schemes are discussed. On the basis of extensive experimental results, the statistical characteristics of the drift phenomenon are obtained and a method to reduce the drift is proposed. Experiments show that the proposed method is effective and results in up to 1 dB gain in the objective quality of the reconstructed pictures.
Keywords/Search Tags:Discrete Cosine Transform, drift, mismatch, MPEG, video coding
PDF Full Text Request
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