Complexity-Scalable Transform Coding Using Variable Complexity Algorithms
DCC '00 Proceedings of the Conference on Data Compression
Modeling DCT coefficients for fast video encoding
IEEE Transactions on Circuits and Systems for Video Technology
Variable complexity DCT approximations driven by an HVQ-based analyzer
IEEE Transactions on Circuits and Systems for Video Technology
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Variable complexity algorithms (VCAs) (i.e. algorithms which take a variable, input-dependent amount of time to complete a task) have been proposed to reduce the average computational complexity of compression algorithms for images and videos. In this paper we introduce a new 2-D variable-complexity DCT that can be used to replace the regular discrete cosine transform (DCT), if only a part of DCT coefficients need to be computed. Consequently, the computational complexity of the DCT can be reduced at the cost in degradation of the reconstructed image quality. We investigate fine-grained complexity-distortion tradeoffs for the proposed variable-complexity, separable DCT (VS-DCT). The evaluation includes a theoretical computational complexity analysis of the VS-DCT in terms of the number of additions and multiplications (note in this paper computational complexity does not refer to the polynomial order of operations) and empirical complexity-distortion curves of the VS-DCT running on two distinct platforms, including a desktop personal computer and an embedded system. The results of evaluation show that our VS-DCT can reduce the computational complexity of a regular DCT by up to 10% for every 3dB decrease in the PSNR (peak signal-to-noise ratio) of the reconstructed images.