Highly Efficient Video Codec for Entertainment Quality Seyoon Jeong Sung Chang Lim Hahyun Lee Jongho Kim Jin Soo Choi and Haechul Choi We present a novel video codec for supporting entertainment quality video It has new coding tools such as an intra prediction with offset integer sine transform and enhanced block based adaptive loop filter These tools are used adaptively in the processing of intra prediction transform and loop filtering In our experiments the proposed codec achieved an average reduction of 13 35 in BD rate relative to H 264 AVC for 720p sequences Keywords Video coding H 264 AVC coding efficiency Manuscript received Mar 6 2010 revised Oct 11 2010 accepted Oct 25 2010 The work was supported by the IT R D program KI001932 Development of Next Generation DTV Core Technology of KEIT KCC MKE Rep of Korea Seyoon Jeong phone 82 42 860 5724 email jsy etri re kr Sung Chang Lim email sclim etri re kr Hahyun Lee email hanilee etri re kr Jongho Kim email pooney etri re kr and Jin Soo Choi email jschoi etri re kr are with the Broadcasting Telecommunications Convergence Research Laboratory ETRI Daejeon Rep of Korea Haechul Choi corresponding author email choihc hanbat ac kr is with the Division of Information Communication and Computer Engineering Hanbat National University Daejeon Rep of Korea doi 10 4218 etrij 11 0110 0126 ETRI Journal Volume 33 Number 2 April 2011 2011 I Introduction A large quantity of video material is already being distributed digitally over broadcast channels digital networks and packaged media More and more of this material will be distributed with increased resolution and quality Recently 4k 2k video 3840 2160 digital cameras have already shown up in the market and display devices supporting 4k 2k spatial resolution are also appearing on the horizon In addition digital cinema is now capturing 4k 2k video to provide a captivating entertainment quality experience Evolution in technology will soon make possible the capture and display of video material with a quantum leap in quality whereas networks are already finding it difficult to carry a large number of data rates for HDTV resolution to the end user Moreover further data rate increases resulting from 4k 2k video will put additional pressure on the networks Therefore a new video compression technology that has sufficiently higher compression capability than the existing H 264 Advanced Video Coding AVC 1 standard is needed The ISO IEC JTC1 SC29 WG11 Moving Picture Experts Group MPEG and ITU T Q 6 16 Video Coding Experts Group VCEG have jointly started a new video coding standard that is tentatively named high efficiency video coding HEVC and they publically issued a call for proposals on HEVC in January 2010 2 3 These standard groups urgently encourage new video coding algorithms for their new video coding standards In accordance with the status of such a new standard we propose an enhanced video codec for entertainment quality applications such as DVD video systems HDTV and 4k 2k video systems In such applications video sequences have Seyoon Jeong et al 145 720 480 resolution and beyond and those bitrates are larger Transform Entropy cosine than 3 Mb s For high coding efficiency delay can be allowed Bitstream Quantization coding The proposed codec has novel video coding tools including an IST intra prediction with offset IPO integer sine transform IST Dequantization and enhanced block based adaptive loop filter E BALF These tools are used adaptively in the processing of intra Inverse Inverse transform prediction transforms and loop filtering Moreover by IST cosine Intra prediction combining these tools on the top of H 264 AVC we Intra offset accomplish a video codec that can provide high performance coding efficiency for entertainment quality video Motion Deblocking compensation This paper is structured as follows Section II describes the E BALF filter proposed video codec including new coding tools Section III Motion estimation shows experimental results followed by a conclusion in section IV Fig 1 Encoder block diagram of proposed video codec Gray II High Coding Efficient Video Codec 1 Codec Overview The encoder structure of H 264 AVC is illustrated in Fig 1 It also includes our proposed coding tools which are presented with gray boxes As shown in Fig 1 a typical block based hybrid video codec is composed of many processes including intra prediction and interprediction transforms quantization entropy coding and filtering Video coding technologies have been maturing through intensive research and development for a long time To achieve significantly higher coding efficiency than current mature video codecs various coding tools covering many processes must be developed in an efficiently combined way We have thoroughly studied H 264 AVC which is the stateof the art video coding standard to improve its coding performance To obtain more attractive quality than the best one supported by H 264 AVC at the same bitrate we have developed various normative algorithms that change both the decoding and encoding processes The proposed video codec has three novel coding tools including the IPO IST and EBALF These proposed tools are switchable and thus each of them is selectively used in the sense of rate distortion optimization RDO An IPO is an intra predictive coding tool that estimates an original signal by referring to reconstructed signals within a current slice An accurate prediction can reduce the quantity of the signal to be coded This is because only a residual signal which is the difference between the original and predictive signals is transmitted An IPO compensates for the DC difference between the original and reference signals and can produce a more accurate prediction signal particularly in cases where there is an illumination change across spatial regions An IST is a sine transform that can compact a low correlated 146 Seyoon Jeong et al boxes are the proposed tools and white boxes are H 264 AVC tools signal more highly than the integer transform of H 264 based on the cosine transform 4 The higher compaction can lead to higher compression with the help of an appropriate quantization method such as a nonlinear quantizer arranging larger step sizes at higher frequency An IST can be applied to all signals regardless of the prediction method whether it be the intra prediction inter prediction or differential pulse code modulation An E BALF is an adaptive loop filter used to enhance the subjective
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