Effective subblock-based and pixel-based fast direction detections for H.264 intra prediction

An Chao Tsai, Jhing Fa Wang, Jar-Ferr Yang, Wei Guang Lin

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)


In H.264/AVC intra-frame coding, the rate-distortion optimization (RDO) is employed to select the optimal coding mode to achieve the minimum rate-distortion cost. Due to a large number of combinations of coding modes, the computational burden becomes extremely high in intra-prediction. In this paper, we propose two fast, efficient but reliable direction detection algorithms by computing subblock and pixel direction differences. Both proposed methods effectively estimate the edge direction inside the block to narrow down the predictive modes to reduce the RDO computation. Experimental results show that the proposed methods can reduce the encoding time by about 60% with negligible loss of coding performance. For hardware realization, a fast mode decision VLSI circuit for intra-prediction with the silicon core size of 0.12 × 0.12 mm2 at 0.18-μm CMOS technology is implemented. The fast mode decision VLSI in three-stage pipelined architecture operated at 173 MHz can encode 30 fps real-time videos up to Level 5.

Original languageEnglish
Article number4472179
Pages (from-to)975-982
Number of pages8
JournalIEEE Transactions on Circuits and Systems for Video Technology
Issue number7
Publication statusPublished - 2008 Jul 1

All Science Journal Classification (ASJC) codes

  • Media Technology
  • Electrical and Electronic Engineering


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