Efficient hierarchical inter picture coding for H.264/AVC baseline profile (original) (raw)

H.264 hierarchical P coding in the context of ultra-low delay, low complexity applications

28th Picture Coding Symposium, 2010

Despite the attention that hierarchical B picture coding has received, little attention has been given to a related technique called hierarchical P picture coding. P picture only coding without reverse prediction is necessary in constrained bit rate applications that require ultra-low delay and/or low complexity, such as videoconferencing. Such systems, however, have been using the traditional IPPP picture coding structure almost exclusively. In this paper, we investigate the use of hierarchical P coding vs. traditional IPPP coding and demonstrate that it has significant advantages which have not yet been well documented or understood. From a pure coding efficiency point of view, we show that for encoders configured to use ultra-low delay and low complexity coding tools, hierarchical P coding achieves an average advantage of 7.86% BD-rate and 0.34 dB BD-SNR.

Multiple Description Coding Scheme for H. 264/AVC Intra Slices

This paper proposes a Multiple Description Scalar Quantisation (MDSQ) coding scheme for H.264/AVC intra slices which is based on a multi-loop structure to prevent distortion accumulation at the decoder due to drift in intra predicted blocks. The drift distortion is reduced by sending a controlled amount of redundant information to be used whenever any of the descriptions fails to reach the decoder. The experimental results show that the quality of intra coded slices is significantly improved (e.g., 6-8 dB) at reduced redundancy cost, (e.g., 0.2-0.25), in comparison with the open loop MDSQ implementation.

Joint Optimization of Transform Coefficients for Hierarchical B Picture Coding in H.264/AVC

2007 IEEE International Conference on Image Processing, 2007

Coding of video sequences using hierarchical B pictures in the Joint Scalable Video Model (JSVM) for the scalability amendment of H.264/AVC has the benefit of improved rate distortion efficiency relative to other known temporal decomposition structures, besides providing temporal scalability. In the operational encoder control of the JSVM, the inter-picture dependencies within a hierarchical B picture structure are considered using a heuristic, where pictures that are more frequently used for motion compensation are coded with higher fidelity compared to pictures that are less often used for motion compensation. In this paper, we describe an approach where the dependencies introduced by motion compensation are also considered when selecting transform coefficient values.

Rate control algorithm based on intra-picture complexity for H.264/AVC

IET Image Processing, 2009

An efficient rate control algorithm based on the content-adaptive initial quantisation parameter (QP) setting scheme and the peak signal-to-noise ratio (PSNR) variation-limited bit-allocation strategy for lowcomplexity mobile applications is presented. This algorithm can efficiently measure the residual complexity of intra-pictures without performing the computation-intensive intra-prediction and mode decision in H.264/AVC, based on the structural and statistical features of local textures. This can adaptively set proper initial QP values for versatile video contents. In addition, this bit-allocation strategy can effectively distribute bit-rate budgets based on the monotonic property to enhance overall coding efficiency while maintaining the consistency of visual quality by limiting the variation of quantisation distortion. The experimental results reveal that the proposed algorithm surpasses the conventional rate control approaches in terms of the average PSNR from 0.34 to 0.95 dB. Moreover, this algorithm provides more impressive visual quality and more robust buffer controllability when compared with other algorithms.

An efficient algorithm for H.264/AVC high definition video coding

IEEE Transactions on Consumer Electronics, 2008

Quality consistency has been an important issue in video applications. However, the quality fluctuation cannot be avoided in single pass video coding due to the variation of the video content, flexible coding structure, different frame types, etc. In this paper, we propose an efficient method to reduce the quality fluctuation for H.264/AVC high definition (HD) video coding. We aim to reduce the distortion variation among frames at different types. A single-pass distributed control algorithm is introduced which provides different control mechanism for different frame type. For P frame, the quantization parameter is decided by the relationship between the quantization step and the given target bit rate and the buffer status to satisfy the bit rate constraints. For B frame, the quantization parameter is determined by the relationship between the quantization step and the given target distortion to reduce the quality fluctuation between P and B frames. Extensive simulation results are provided to demonstrate the efficiency of the proposed method. When compared to the traditional method used in current H.264/AVC video coding, the quality fluctuations are significantly reduced. Moreover, the bit rate constraints of the high definition video coding are satisfied 1 .

Adaptive Quantization Parameter Selection For H.265/HEVC by Employing Inter-Frame Dependency

IEEE Transactions on Circuits and Systems for Video Technology, 2017

Rate-distortion optimization (RDO) is widely applied in video coding, which aims at minimizing the coding distortion at a target bitrate. Conventionally, RDO is performed independently on each individual frame to avoid high computational complexity. However, extensive use of temporal/spatial predictions result in strong coding dependencies among neighboring frames, which make the current RDO be non-optimally used. To further improve video coding performance, it would be desirable to perform global RDO among a group of neighboring frames while maintaining approximately the same coding complexity. In this paper, the problem of global RDO is studied by jointly determining the quantization parameters (QPs) for a group of neighboring frames. Specifically, an adaptive frame-level QP selection algorithm is proposed for the H.265/HEVC random access (RA) coding by taking into account the inter-frame dependency. To measure the inter-frame dependency, a model based on the energy of prediction residuals is first established. With the help of the model, the problem of global RDO is then analyzed for the hierarchical coding structure in H.265/HEVC. Finally, the QP and the corresponding Lagrangian multiplier for each coding frame are determined adaptively by considering the total impact of its coding distortion on that of future frames in the encoding order. Experimental results show that in comparison with HM-16.0, the proposed algorithm reduces, on average, the BD-rate by 3.49% with negligible increase of encoding time. In addition, the quality fluctuation of the coded video by the proposed algorithm is lower than that by HM-16.0.

Multi-scale, Perceptual and Vector Quanitzation Based Video Codec

2007 Second International Conference on Digital Telecommunications (ICDT'07), 2007

This paper presents a novel hybrid Multi-scale, perceptual and vector quantization based video coding scheme. In intra mode of operation, a wavelet transform is applied to the input frame and decorrelate it into a number of subbands. The lowest frequency subband is losslessly coded. The coefficient of the high frequency subbands are pixel quantized using perceptual weights, which specifically designed for each high frequency subband. The quantized coefficients are then coded using quadtree-coding scheme. In the inter mode of operation, displaced frame difference is generated using overlapped block motion estimation / compensation to exploit the interframe redundancy. A wavelet transform is then applied to the displaced frame difference to decorrelate it into a number of subbands. The coefficients in the resulting subbands are coded using an adaptive vector quantization scheme.

Multiresolution, perceptual and vector quantization based video codec

Multimedia Tools and Applications, 2012

This paper presents a novel Multiresolution, Perceptual and Vector Quantization (MPVQ) based video coding scheme. In the intra-frame mode of operation, a wavelet transform is applied to the input frame and decorrelates it into its frequency subbands. The coefficients in each detail subband are pixel quantized using a uniform quantization factor divided by the perceptual weighting factor of that subband. The quantized coefficients are finally coded using a quadtree-coding algorithm. Perceptual weights are specifically calculated for the centre of each detail subband. In the inter-frame mode of operation, a Displaced Frame Difference (DFD) is first generated using an overlapped block motion estimation/compensation technique. A wavelet transform is then applied on the DFD and converts it into its frequency subbands. The detail subbands are finally vector quantized using an Adaptive Vector Quantization (AVQ) scheme. To evaluate the performance of the proposed codec, the proposed codec and the adaptive subband vector quantization coding scheme (ASVQ), which has been shown to outperform H.263 at all bitrates, were applied to six test sequences. Experimental results indicate that the proposed codec outperforms the ASVQ subjectively and objectively at all bit rates.

Improving the quality of H.264/AVC by using a new rate-quantization model

Image Quality and System Performance VIII, 2011

Rate control plays a key role in video coding standards. Its goal is to achieve a good quality at a given target bit-rate. In H.264/AVC, rate control algorithm for both Intra and Inter-frames suffers from some defects. In the Intra-frame rate control, the initial quantization parameter (QP) is mainly adjusted according to a global target bit-rate and length of GOP. This determination is inappropriate and generates errors in the whole of video sequence. For Inter coding unit (Frame or Macroblock), the use of MAD (Mean Average Differences) as a complexity measure, remains inefficient, resulting in improper QP values because the MAD handles locally images characteristics. QP miscalculations may also result from the linear prediction model which assumes similar complexity from coding unit to another. To overcome these defects, we propose in this paper, a new Rate-Quantization (R-Q) model resulting from extensive experiments. This latter is divided into two models. The first one is an Intra R-Q model used to determine an optimal initial quantization parameter for Intraframes. The second one is an Inter R-Q model that aims at determining the QP of Inter coding unit according to the statistics of the previous coded ones. It does not use any complexity measure and substitutes both linear and quadratic models used in H.264/AVC rate controller. Objective and subjective simulations have been carried out using JM15.0 reference software. Compared to this latter, the global R-Q model (Intra and Inter models combined) improves the coding efficiency in terms of PSNR, objectively (up to +2.01dB), subjectively (by psychophysical experiments) and in terms of computational complexity.

Evaluation of H.264/AVC Coding Elements and New Improved Scalability/Adaptation Algorithm/Methods

IOSR Journal of Electronics and Communication Engineering, 2014

In this paper, we evaluated the major coding elements/parameters of H.264/AVC and their significant differences with the prior standards. The design parameters of H.264/AVC codec are experimented with and analysed. The influences of the parameters and other coding elements on scalable bitstream and their level of adaptation over multi-channel networks are also evaluated. Objective and real-time analysis are employed in the evaluation. To enhance the flexibility and robustness of codec adaptation over heterogeneous networks, Qp Constraint Algorithm is developed that reveals bits reduction up to 100kbits depending on the current bitrates. The usage of slice groups is implemented and the result shows that, the implementation of slice groups can support flexible adaptation and data protection. We also propose and experimentally evaluate methods for multi-channels adaptation.