An adaptive preprocessing algorithm for low bitrate video coding
- 55 Downloads
At low bitrate, all block discrete cosine transform (BDCT) based video coding algorithms suffer from visible blocking and ringing artifacts in the reconstructed images because the quantization is too coarse and high frequency DCT coefficients are inclined to be quantized to zeros. Preprocessing algorithms can enhance coding efficiency and thus reduce the likelihood of blocking artifacts and ringing artifacts generated in the video coding process by applying a low-pass filter before video encoding to remove some relatively insignificant high frequent components. In this paper, we introduce a new adaptive preprocessing algorithm, which employs an improved bilateral filter to provide adaptive edge-preserving low-pass filtering which is adjusted according to the quantization parameters. Whether at low or high bit rate, the preprocessing can provide proper filtering to make the video encoder more efficient and have better reconstructed image quality. Experimental results demonstrate that our proposed preprocessing algorithm can significantly improve both subjective and objective quality.
Key wordsBlocking artifact Quantization parameter Video preprocessing Bilateral filtering
Unable to display preview. Download preview PDF.
- Huang, S.J., 1997. Adaptive Noise Reduction and Image Sharpening for Digital Video Compression. Proc. IEEE Int. Conf. Computational Cybernetics Simulation, 4:3142–3147. [doi:10.1109/ICSMC.1997.633077]Google Scholar
- ITU-T, 1998. Video Coding for Low Bitrate Communication. ITU-T Recommendation H.263, Version 2.Google Scholar
- Kimata, H., Yashima, Y., Kobayashi, N., 2001. Edge Preserving Pre-post Filtering for Low Bitrate Video Coding. Proc. of IEEE ICIP 2001, Thessaloniki, Greece, 3:554–557.Google Scholar
- Pham, T.Q., van Vliet, L.J., 2005. Separable Bilateral Filtering for Fast Video Preprocessing. Proc. of IEEE ICME 2005, Amsterdam, the Netherlands, p.454–457.Google Scholar
- Richardson, I.E.G., 2002. Video Codec Design. John Wiley & Sons, Ltd., p.136–137.Google Scholar
- Shen, K., 1999. Video Preprocessing Techniques for Real-time Video Compression-noise Level Estimation Techniques. Proc. of IEEE Int. Symposium on Circuits and Systems (ISCAS), 2:778–781.Google Scholar
- Tomasi, C., Manduchi, R., 1998. Bilateral Filtering for Gray and Color Images. Sixth International Conference on Computer Vision, p.839–846. [doi:10.1109/ICCV.1998.710815]Google Scholar
- Webb, J.L.H., 1996. Postprocessing to Reduce Blocking Artifacts for Low Bit-rate Video Coding Using Chrominance Information. Proc. of IEEE ICIP 1996, Lausanne, Switzerland, 2:9–12.Google Scholar