Fast Rate-Distortion Optimization in H.264/AVC Video Coding
One of the new features in the H.264/AVC encoder is the use of Lagrangian Rate-Distortion Optimised (RDO) mode decision at the macroblock (MB) level. This brute-force algorithm searches through the 10 different MB coding modes to obtain the best one for encoding that MB, and is hence computationally expensive. This paper proposes a novel algorithm where the RDO can be reorganized in a better order such that the most likely MB modes will be tried first, and an early termination of the RDO process will be used once the calculated rate-distortion cost (RDcost) is below a preset threshold. The preset threshold is dependent on the RDcost of previous and neighbouring MBs that have been coded. This is based on the observation that the RDcost of an MB in the current frame is highly correlated to a co-located MB in the previous frame. Experimental results have shown that the new algorithm has dramatically reduced the encoding times of up to 61.8%, with negligible increases in bit-rates or PSNR.
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- 1.Information technology - Coding of audio-visual objects - Part 10: Advanced video coding, Final Draft International Standard, ISO/IEC FDIS 14496-10 (December 2003)Google Scholar
- 2.Report of The Formal Verification Tests on AVC (ISO/IEC 14496-10 | ITU-T Rec. H.264), MPEG/N6231, Waikoloa, USA (December 2003)Google Scholar
- 3.Sullivan, G., Wiegand, T., Lim, K.-P.: Joint Model Reference Encoding Methods and Decoding Concealment Methods, JVT-I049d0, 9th JVT Meeting, San Diego, United States (September 2003)Google Scholar
- 4.Richardson, I.E.G.: H.264/MPEG-4 Part 10 White Paper. Prediction of Macroblocks in P-Slices, http://www.vcodex.fsnet.co.uk/h264_interpred.pdf
- 5.Richardson, I.E.G.: H.264/MPEG-4 Part 10 White Paper. Prediction of Intra Macroblocks, http://www.vcodex.fsnet.co.uk/h264_intrapred.pdf
- 6.Chen, Z., Zhou, P., He, Y.: Fast Integer Pel and Fractional Pel Motion Estimation for JVT, JVT-F017, 6th Meeting, Awaji Island, Japan, December 5-13 (2002)Google Scholar
- 8.Pan, F., Lin, X., Rahardja, S., Lim, K.P., Li, Z.G., Feng, G.N., Wu, D.J., Wu, S.: Fast Mode Decision Algorithm for JVT Intra Prediction. JVT-G013, 7th JVT Meeting, Pattaya II, Thailand (March 2003)Google Scholar
- 9.Lim, K.P., Wu, S., Wu, D.J., Rahardja, S., Lin, X., Pan, F., Li, Z.G.: Fast Inter Mode Decision. JVT-I020, 9th JVT Meeting, San Diego, United States (September 2003)Google Scholar
- 11.Ghanbari, M.: Standard Codecs: Image Compression to Advanced Video Coding. In: Institute of Electrical Engineers, London, UK (2003)Google Scholar
- 12.Sullivan, G.: Recommended Simulation Common Conditions for H.26L Coding Efficiency Experiments on Low Resolution Progressive Scan Source Material. In: VCEG-N81, 14th meeting, Santa Barbara, CA, USA, September 24-27 (2001)Google Scholar
- 13.JVT Test Model Ad Hoc Group, Evaluation Sheet for Motion Estimation, Draft version 4, February 19 (2003)Google Scholar
- 14.Bjontegaard, G.: Calculation of Average PSNR Differences between RD-curves. In: VCEG-M33, 13th meeting, Austin, Texas, USA, April 2-4 (2001)Google Scholar