My varied experience has expanded my knowledge of digital data compression and enriched my skill sets in designing software and debugging that one for embedded systems. One of the most significant of these was the ‘High Efficiency of Audio/Video Codec Research’ with Electronics and Telecommunications Research Institute. Through this project, I gained invaluable product development experience from conception and design to enhance the coding efficiency of H.264/AVC. What’s more, after graduation I was working as a software engineer in a set-top box company, which is one of the world’s largest manufactures of digital set-top boxes over 2 years. I would like to describe myself as self-motivated, quick-learner, single-minded, team player that possesses communication skills so I could take part in developing and designing one of a quite important part of software modules as a staff.
A New Inter Coding Scheme for Improving Video Coding Efficiency
As the inter coding scheme in H.264/AVC, P_Skip coding mode is effective as well as P_16×16 mode especially. As the result of macroblock basis coding mode decision based on R-D optimization criteria, those two modes are frequently selected because the R-D optimal point locates between those two candidates on the approximated R-D curve. However, the R-D optimal point is far from points corresponding to those two candidates, and this problem becomes significant under low bit-rate. Therefore, a new coding mode that can provide the intermediate R-D performance between P_Skip and P_16×16, is expected to improve the coding efficiency. In this paper, we propose a new coding mode for P-picture based on extending conventional P_16×16 mode in order to improve coding performance. In this coding mode, MV information is coded by a scheme similar to P_16×16, and only the average value of the residual signal is coded. Simulation results reveal a performance increase up to 11.38% overall rate savings and 0.34 dB in peak signal-to-noise ratio.
New Intra Coding Scheme for Improving Video Coding Efficiency
J.E. Kim, D.Y. Noh, S.Y. Jeoung, J.H. Lee, and S.J. Oh
H.264/AVC significantly outperforms the previous video coding standards with many new coding tools. Among these tools, several intra-block coding tools can particularly improve coding efficiency. For intra prediction, H.264/AVC supports most probable mode in the entropy coding process to reduce syntax elements indicating intra prediction modes and most probable mode selection ratio is very high. Also, in general, natural images and videos have many homogeneous regions whose high correlation with neighbouring blocks. In this paper, we propose intra prediction mode SKIP mode using decoder-side prediction to improve the coding efficiency. The proposed method is determined the optimal prediction mode using only neighbouring block's information and coded on the basis of the conventional prediction/transform coding. And the prediction modes are not send to decoder at all. Skipped intra prediction mode is determined by decoder. Experimental results show that the proposed method achieves coding gains of 1.40% for common intermediate format(CIF), 3.24% for 720p sequences against the H.264/AVC JM 17.0 reference software.
A New Method for Thumbnail Extraction in H.264/AVC Bitstream
S.H. Hong, J.E. Kim, Y.M. Jin, J.C. Kwan, and S.J. Oh
Recently, thumbnail techniques are required to index a high-performance video at digital convergence-based multimedia service like IPTV and DMB. Therefore a thumbnail extraction method in H.264/AVC bitstreams has been proposed. However, thumbnail quality deterioration problem at converting the general equation of spatial domain to frequency domain which is generated by not considering about H.264/AVC transform and quantization processing and rounding-off operation in intra prediction. In this paper, we propose a new thumbnail extraction method in H.264/AVC bitstreams. The proposed scheme is based on H.264/AVC core-transform for a thumbnail extraction in frequency domain, and probability theory, intra rounding-off error compensation. Through the implementation and performance evaluation, the subjective quality difference between the output of our scheme and the output of reference decoder is negligible and better than the conventional method, and moreover PSNR gain by up to 8.66 dB.
Voting-based Intra Mode Bit Skip Using Pixel Information in Neighbor Blocks
J.E. Kim, H.J. Cho, S.Y. Jeong, J.H. Lee, and S.J. Oh
Intra coding is an indispensable coding tool since it can provide random accessibility as well as error resiliency. However, it is the problem that intra coding has relatively low coding efficiency compared with inter coding in the area of video coding. Even though H.264/AVC has significantly improved the intra coding performance compared with previous video standards, H.264/AVC encoder complexity is significantly increased, which is not suitable for low bit rate interactive services. In this paper, a Voting-based Intra Mode Bit Skip (V-IMBS) scheme is proposed to improve coding efficiency as well as to reduce encoding time complexity using decoder-side prediction. In case that the decoder can determine the same prediction mode as what is chosen by the encoder, the encoder does not send that intra prediction mode; otherwise, the conventional H.264/AVC intra coding is performed. Simulation results reveal a performance increase up to 4.44% overall rate savings and 0.24 dB in peak signal-to-noise ratio while the frame encoding speed of proposed method is about 42.8% better than that of H.264/AVC.
Developer, LTE Test Automation
Software Engineer, IP-STB Middleware / Application
Video/Image Signal Processing
Embedded System, Microcontroller(8051, AVR, ARM, DSP)
Queen Mary, University of London,
School of Electronic Engineering and Computer Science, UK
E-mail : email@example.com