A low-complexity parallel-friendly rate control algorithm for ultra-low delay high definition video coding

Ultra-low delay high definition (HD) video coding applications such as video conferencing demand, first, low-complexity video encoders able to support multi-core framework for parallel processing and, second, rate control algorithms (RCAs) for successful video content delivering under delay constraints. In this paper a low-complexity parallel-friendly RCA is proposed for HD video conferencing. Specifically, it has been implemented on an optimized H.264/Scalable Video Coding (SVC) encoder, providing excellent performance in terms of buffer control, while achieving acceptable quality of compressed video under the imposed delay constraints

New Fast Search Algorithm for Base Layer of H.264 Scalable Video Coding Extension

In this contribution, a fast search motion estimation algorithm for H.264/AVC SVC (scalable video coding) [2] base layer with hierarchical B-frame structure for temporal decomposition is presented and compared with fast search motion estimation algorithm in JSVM software [1], that is the reference software for H.264/AVC SVC. The proposed technique is a block-matching based motion estimation algorithm working in two steps, called Coarse search and Fine search. The Coarse search is performed for each frame in display order, and for each 16x16 macroblock chooses the best motion vector at half pel accuracy. Fine search is performed for each frame in encoding order and finds the best prediction for each block type, reference frame and direction, choosing the best motion vector at quarter pel accuracy using R-D optimization. Both Coarse and Fine Search test 3 spatial and 3 temporal predictors, and add to the best one a set of updates. The spatial predictors for the fine search are the result of the Fine search already performed for the previous blocks, while the temporal predictors are the results of Coarse Search scaled by an appropriate coefficient. This scaling is performed since in the Coarse search each picture is always estimated with respect to the previous one, while in the Fine Search the temporal distance between the current picture and its references depend on the temporaldecomposition level. Moreover in Fine search the number and the value of the updates tested depend on the distance between the current picture and its references. These sets of updates are the result of a huge number of simulations on test sequences with different motion features. The proposed algorithm has been tested on the set of test sequences proposed by JVT group, using different resolutions and temporal decomposition structures. The proposed method can reduce the average coding complexity in terms of motion vector tested from 70 to 90 percent with respect to the Fast-ME JVT method, while the quality loss depends on the GOP dimension, that is the most critical parameter for the performance of the algorithm. In fact for small GOP dimensions (4 or 8) the algorithm has the same quality at equal bit-rate respect to the Fast-ME JVT method for almost all the sequences and better quality for some sequences. For medium and long GOP dimensions (16-32) the algorithm has a quality loss lower than 0.5 dB for all the tested sequences

A parallel H.264/SVC encoder for high definition video conferencing

In this paper we present a video encoder specially developed and configured for high definition (HD) video conferencing. This video encoder brings together the following three requirements: H.264/Scalable Video Coding (SVC), parallel encoding on multicore platforms, and parallel-friendly rate control. With the first requirement, a minimum quality of service to every end-user receiver over Internet Protocol networks is guaranteed. With the second one, real-time execution is accomplished and, for this purpose, slice-level parallelism, for the main encoding loop, and block-level parallelism, for the upsampling and interpolation filtering processes, are combined. With the third one, a proper HD video content delivery under certain bit rate and end-to-end delay constraints is ensured. The experimental results prove that the proposed H.264/SVC video encoder is able to operate in real time over a wide range of target bit rates at the expense of reasonable losses in rate-distortion efficiency due to the frame partitioning into slices

Cross-layer H.264 scalable video downstream delivery over WLANs

Thanks to its in-network drop-based adaptation capabilities, H.264 Scalable Video Coding is perceived as an effective approach for delivering video over networks characterized by sudden large bandwidth fluctuations, such as Wireless LANs. Performance may be boosted by the adoption of application-aware/cross-layer schedulers devised to intelligently drop video data units (NALUs), so that i) decoding dependencies are preserved, and ii) the quality perceived by the end users is maximized. In this paper, we provide a theoretical formulation of a QoE utility-optimal cross-layer scheduling problem for H.264 SVC downlink delivery over WLANs. We show that, because of the unique characteristics of the WLAN MAC operation, this problem significantly differs from related approaches proposed for scheduled wireless technologies, especially when the WLAN carries background traffic in the uplink direction. From these theoretical insights, we derive, design, implement and experimentally assess a simple practical scheduling algorithm, whose performance is very close to the optimal solution

Streaming H.264 scalable video over data distribution service in a wireless environment

The Data Distribution Service (DDS) middleware is enjoying a rapid adoption in high-performance, mission-critical networks. At the same time, the H.264 Scalable Video Coding (SVC) has been recently standardized and it is deemed to be an effective solution for video streaming over a channel with time-varying bandwidth, like the wireless one. In these conditions, it is critical to adapt the video bit-rate to the actual wireless capacity, and bit-rate adaptation is extremely simple for a H.264 SVC video. In this paper we devise, evaluate and demonstrate a technique for streaming H.264 SVC video over a DDS middleware. The contribution is threefold: i) we design a structure of the DDS data-unit able to carry H.264 SVC video-units; ii) we devise a receiver-driven rate-control mechanism based on our DDS data-unit and exploiting specific DDS functionality; iii) we implement and show the effectiveness of our mechanism in an 802.11 wireless scenario, comparing our proposal with other solution

Rate Control Initialization Algorithm for Scalable Video Coding

Proceeding of: 18th IEEE International Conference on Image Processing (ICIP), 2011.In this paper we propose a novel rate control initialization algorithm for real-time H.264/scalable video coding. In particular, a two-step approach is proposed. First, the initial quantization parameter (QP) for each layer is determined by means of a parametric rate-quantization (R-Q) modeling that depends on the layer identifier (base or enhancement) and on the type of scalability (spatial or quality). Second, an intra-frame QP refinement method that allows for adapting the initial QP value when needed is carried out over the three first coded frames in order to take into consideration both the buffer control and the spatio-temporal complexity of the scene. The experimental results show that the proposed R-Q modeling for initial QP estimation, in combination with the intra-frame QP refinement method, provide a good performance in terms of visual quality and buffer control, achieving remarkably similar results to those achieved by using ideal initial QP values.The Spanish National grant TSI-020110-2009-103 (AFICUS) and the Regional grant CCG10-UC3M/TIC-5570 (AMASSACA).Publicad

RBF-Based QP Estimation Model for VBR Control in H.264/SVC

In this paper we propose a novel variable bit rate (VBR) controller for real-time H.264/scalable video coding (SVC) applications. The proposed VBR controller relies on the fact that consecutive pictures within the same scene often exhibit similar degrees of complexity, and consequently should be encoded using similar quantization parameter (QP) values for the sake of quality consistency. In oder to prevent unnecessary QP fluctuations, the proposed VBR controller allows for just an incremental variation of QP with respect to that of the previous picture, focusing on the design of an effective method for estimating this QP variation. The implementation in H.264/SVC requires to locate a rate controller at each dependency layer (spatial or coarse grain scalability). In particular, the QP increment estimation at each layer is computed by means of a radial basis function (RBF) network that is specially designed for this purpose. Furthermore, the RBF network design process was conceived to provide an effective solution for a wide range of practical real-time VBR applications for scalable video content delivery. In order to assess the proposed VBR controller, two real-time application scenarios were simulated: mobile live streaming and IPTV broadcast. It was compared to constant QP encoding and a recently proposed constant bit rate (CBR) controller for H.264/SVC. The experimental results show that the proposed method achieves remarkably consistent quality, outperforming the reference CBR controller in the two scenarios for all the spatio-temporal resolutions considered.Proyecto CCG10-UC3M/TIC-5570 de la Comunidad Autónoma de Madrid y Universidad Carlos III de MadridPublicad

No tradeoff between confidentiality and performance: An analysis on H.264/SVC partial encryption

Agency for Science, Technology and Research (A*STAR

Advanced solutions for quality-oriented multimedia broadcasting

Multimedia content is increasingly being delivered via different types of networks to viewers in a variety of locations and contexts using a variety of devices. The ubiquitous nature of multimedia services comes at a cost, however. The successful delivery of multimedia services will require overcoming numerous technological challenges many of which have a direct effect on the quality of the multimedia experience. For example, due to dynamically changing requirements and networking conditions, the delivery of multimedia content has traditionally adopted a best effort approach. However, this approach has often led to the end-user perceived quality of multimedia-based services being negatively affected. Yet the quality of multimedia content is a vital issue for the continued acceptance and proliferation of these services. Indeed, end-users are becoming increasingly quality-aware in their expectations of multimedia experience and demand an ever-widening spectrum of rich multimedia-based services. As a consequence, there is a continuous and extensive research effort, by both industry and academia, to find solutions for improving the quality of multimedia content delivered to the users; as well, international standards bodies, such as the International Telecommunication Union (ITU), are renewing their effort on the standardization of multimedia technologies. There are very different directions in which research has attempted to find solutions in order to improve the quality of the rich media content delivered over various network types. It is in this context that this special issue on broadcast multimedia quality of the IEEE Transactions on Broadcasting illustrates some of these avenues and presents some of the most significant research results obtained by various teams of researchers from many countries. This special issue provides an example, albeit inevitably limited, of the richness and breath of the current research on multimedia broadcasting services. The research i- - ssues addressed in this special issue include, among others, factors that influence user perceived quality, encoding-related quality assessment and control, transmission and coverage-based solutions and objective quality measurements