Fast Bit Rate Estimation for Mode Decision of H.264/AVC

• Published in: IEEE transactions on circuits and systems for video technology Vol. 17; no. 10; pp. 1402 - 1407
• Main Authors: Sarwer, M.G., Lai-Man Po
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Automatic voltage control; Bit rate; Circuit properties; Coding; Coding, codes; Complexity; Computation; Computational efficiency; Context-based variable length coding (CAVLC); Degradation; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Encoding; Entropy; Entropy coding; Exact sciences and technology; H.264/AVC; Image processing; Information, signal and communications theory; Mathematical models; mode decision; Motion estimation; Predictive models; rate estimation; Rate-distortion; rate-distortion (RD) optimization; Signal and communications theory; Signal convertors; Signal processing; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Video coding; Video coding; Performance evaluation; rate-distortion (RD) optimization; Motion estimation; Image processing; Coding circuit; Rate distortion theory; Entropy codes; Information rate; H.264/AVC; Information transmission; Optimization; Video signal processing; rate estimation; Search algorithm; Context-based variable length coding (CAVLC); Degradation; Signal processing; Fast algorithm; mode decision; Variable length code; Damaging
• ISSN: 1051-8215; 1558-2205
• DOI: 10.1109/TCSVT.2007.903787

To achieve the highest coding efficiency, H.264/AVC uses rate-distortion optimization technique. This means that the encoder has to code the video by exhaustively trying all the mode combinations including the different intra- and inter-prediction modes. Therefore, the complexity and computation load of video coding in H.264/AVC increase drastically compared to any previous standards. To reduce the complexity of rate-distortion cost computation, we propose a fast bit rate estimation technique to avoid the entropy coding method during intra- and inter-mode decision of H.264/AVC. The estimation method is based on the properties of context-based variable length coding (CAVLC). The proposed rate model predicts the rate of a 4 times 4 quantized residual block using five different tokens of CAVLC. Experimental results demonstrate that the proposed estimation method reduces about 47% of total encoding time on using intra-modes only and saves about 34% of total encoding time on using both inter- and intra-modes with ignorable degradation of coding performance when the fast motion search algorithm is used. When full search motion estimation algorithm is used, the proposed algorithm reduces about 17% of total encoding time.