I. IntroductionII. High Coding Efficient Video CodecIII. ExperimentsIV. ConclusionReferencesETRI Journal, Volume 33, Number 2, April 2011 © 2011 Seyoon Jeong et al. 145 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: [email protected]), Sung-Chang Lim (email: [email protected]), Hahyun Lee (email: [email protected]), Jongho Kim (email: [email protected]), and Jin Soo Choi (email: [email protected]) are with the Broadcasting & Telecommunications Convergence Research Laboratory, ETRI, Daejeon, Rep. of Korea. Haechul Choi (corresponding author, email: [email protected]) is with the Division of Information Communication and Computer Engineering, Hanbat National University, Daejeon, Rep. of Korea. doi:10.4218/etrij.11.0110.0126 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 Highly Efficient Video Codec for Entertainment-Quality Seyoon Jeong, Sung-Chang Lim, Hahyun Lee, Jongho Kim, Jin Soo Choi, and Haechul Choi146 Seyoon Jeong et al. ETRI Journal, Volume 33, Number 2, April 2011 720×480 resolution and beyond, and those bitrates are larger than 3 Mb/s. For high coding efficiency, delay can be allowed. The proposed codec has novel video coding tools, including an intra prediction with offset (IPO), integer sine transform (IST), and enhanced block-based adaptive loop filter (E-BALF). These tools are used adaptively in the processing of intra prediction, transforms, and loop filtering. Moreover, by combining these tools on the top of H.264/AVC, we accomplish a video codec that can provide high-performance coding efficiency for entertainment-quality video. This paper is structured as follows. Section II describes the proposed video codec including new coding tools. Section III shows experimental results, followed by a conclusion in section IV. 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 state-of-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 E-BALF. 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 Fig. 1. Encoder block diagram of proposed video codec. Gray boxes are the proposed tools, and white boxes are H.264/AVC tools. Transform (cosine)Entropy coding DequantizationInverse transform (cosine) Intra predictionDeblocking filter Motion compensationMotion estimation– BitstreamIntra offsetISTInverse IST E-BALF + Quantization 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
View Full Document
Unlocking...