Bitstream Extraction Research Articles

Multi Look-up Table FPGA Reverse Engineering with Bitstream Extraction and Multiple PIP/PLP Matching

Multi Look-up Table FPGA Reverse Engineering with Bitstream Extraction and Multiple PIP/PLP Matching

Real-time selective video encryption based on the chaos system in scalable HEVC extension

In this paper we propose a real-time selective video encryption solution in the scalable extension of High Efficiency Video Coding (HEVC) standard, referred to as SHVC. The proposed scheme encrypts a set of sensitive SHVC parameters with a minimum delay and complexity overheads. The encryption process is performed at the CABAC binstring level and fulfills both constant bitrate and format compliant video encryption requirements. In addition, it preserves all SHVC functionalities, including bitstream extraction for mid-network adaptation and error resilience.We compare the performance of three selective SHVC encryption schemes: the first scheme encrypts only the lowest SHVC layer, the second encrypts all layers and the last scheme encrypts only the highest layer. The performance of the proposed schemes is assessed over different video encryption criteria, at different scalability configurations and various High Definition (HD) video sequences. Experimental results showed that encrypt only the lowest layer or all layers enables a high security level, while encrypting only the highest layer leads to a perceptual encryption solution, by slightly decreasing the highest layer quality. Moreover, the processing complexity of the proposed solution is assessed in the context of a real-time SHVC decoder. The complexity overhead remains low and does not exceed 6% of the real-time decoding of SHVC video sequences.

Adaptive Video Streaming With Optimized Bitstream Extraction and PID-Based Quality Control

To cope with the challenges brought about by bandwidth fluctuation and improve the experience of watching online videos, an adaptive video streaming system that can adjust video quality according to actual network conditions is proposed based on the scalable video coding (SVC) extension of H.264/AVC. First, a simple and effective linear error model is proposed and verified for quality scalability of SVC. The model exploits the linear feature of pixel value errors and can be used to accurately estimate the distortion caused by discarding any combination of enhancement data packets in an SVC bitstream. On that basis, a greedy-like algorithm is designed to assign each data packet a priority value according to its rate-distortion (R-D) impact, thus enabling R-D optimized bitstream extraction under certain bitrate constraints. Finally, the proportional-integral-derivative (PID) method is utilized to control the video quality adjustment and determine a suitable bitrate for transmission. By monitoring and predicting the past, current, and future bandwidth information, the PID-based quality control algorithm is able to reduce quality fluctuation, while still preserving a high quality level. Experimental results show that compared with the baseline software, the proposed system that integrates the above algorithms can achieve much lower video quality fluctuation, with PSNR variance reduced from 1.24 to 0.69, and at the same time deliver higher video quality, with the PSNR average increased by 0.83 dB.

Joint Rate Allocation of Stereoscopic 3D Videos in Next-Generation Broadcast Applications

3D video is foreseen to be the next natural step in the evolution of digital media. Among various representation formats available for 3D videos, stereoscopic is considered the most mature technology so far. This paper proposes a joint rate allocation scheme for next-generation broadcast applications, in which multiple stereoscopic 3D videos are encoded and transmitted simultaneously. We first propose a scalable stereoscopic video coding scheme that inherits features from scalable video coding. The scalable format makes the rate control of each video as easy as bit-stream extraction. For the two views in stereo videos, the reference view is independently coded to provide backward compatibility, while the auxiliary view is coded using the reference view as a base layer to remove inter-view redundancy. Based on the well-known fact that the human visual system can compensate and conceal the degraded fidelity in one of the two views, provided the other view is encoded at a high quality, the proposed joint rate allocation scheme does adaptive bit allocation between views to obtain high compression efficiency and better quality. Experimental results show that the proposed framework achieves smaller quality fluctuation among videos and higher perceived quality in each video as compared with the existing system.

A fast algorithm of bitstream extraction using distortion prediction based on simulated annealing

Scalable video streams can be extracted to meet the bandwidth limitation of different networks and end-users. Bitstream extraction is usually performed at the network proxy or gateway during transmission, where a low computational complexity is always preferred. How to quickly and accurately select the best resolution combination for a video to meet different bandwidth requirements by each user is crucial in bitstream extraction. In this paper a fast algorithm of bitstream extraction for scalable video is proposed. The interlayer dependency between the base quality layer and the first quality layer was used to predict the distortion of higher quality layers. When quality of every layer is available, the proposed method searches for the optimized combination of quality layers based on simulated annealing. Experimental results show that the proposed method provides an optimized performance, which is significantly higher than that can be achieved by the basic extraction method. Compared to the quality layer based extraction method in the reference software model of H.264/SVC (i.e., JSVM), the proposed algorithm can greatly decrease the decoding times from 2NT to only 2 without losing rate-distortion performance. Furthermore, the proposed method obtains a more smoothed video quality which is always favorable to the observer.

Optimal Frame Rate Allocation and Quantizer Selection for Unicast and Multicast Wireless Scalable Video Communication

In this paper, we present novel schemes for video quality maximization in the context of H.264 scalable video coding-based 4G wireless broadcast and multicast video transmission to heterogeneous multimedia wireless clients. In the first part, we address the issue of optimal frame rate allocation when the multimedia server is constrained by the processing overheads required for tasks such as video encoding, bit-stream extraction, packetization, etc. We demonstrate that the above problem of perceptual quality maximization is well represented by a constrained optimization framework. Based on the system model, we present a closed-form solution for frame rate allocation and a comprehensive algorithm for sum quality maximization. In the second part, we propose a novel rate partitioning-based optimal scalable video (RPSV) transmission framework. A typical wireless multicast group comprises of multimedia clients with varying wireless link qualities. Conventional multicast video transmission is constrained by the broadcast/ multicast group (BMG) subscriber with the worst link capacity. Hence, we propose the RPSV scheme for optimal partitioning of the multicast group for transmission of the H.264-coded base and enhancement scalable video layers. We demonstrate that the optimal wireless link quality-based BMG partition and the associated quantization, time-fraction parameters can be computed by solving a series of convex objective minimization problems and derive a closed-form solution for the convex problem at each step. We compare the results obtained using the above mentioned optimal frame rate allocation and quantization parameter selection schemes with the results obtained using conventional schemes and demonstrate the superiority of the proposed algorithms in both unicast and multicast scenarios.

Efficient bitstream extraction for scalable video based on simulated annealing

SUMMARYThis paper presents an efficient method for bitstream extraction for scalable video based on simulated annealing. Following the same spirit as annealing, the proposed method searches for the optimized combination of quality layers for extraction through slowly reducing the simulated temperature according to the characteristics of frames in different temporal levels. Experimental results show that the proposed method provides an optimized performance, which is significantly higher than that of the basic extraction method. When compared with the quality layer‐based extraction method in the reference software model of H.264/SVC (Joint Scalable Video Model), the proposed method can achieve a similar rate‐distortion performance with a significantly reduced computational complexity. Furthermore, the proposed method can obtain a more smoothed video quality, which is always preferable by the end user. Copyright © 2011 John Wiley & Sons, Ltd.

A Framework for Scalable Summarization of Video

Video summaries provide compact representations of video sequences, with the length of the summary playing an important role, trading off the amount of information conveyed and how fast it can be visualized. This letter proposes scalable summarization as a method to easily adapt the summary to a suitable length, according to the requirements in each case, along with a suitable framework. The analysis algorithm uses a novel iterative ranking procedure in which each summary is the result of the extension of the previous one, balancing information coverage and visual pleasantness. The result of the algorithm is a ranked list, a scalable representation of the sequence useful for summarization. The summary is then efficiently generated from the bitstream of the sequence using bitstream extraction.

An integrated approach to summarization and adaptation using H.264/MPEG-4 SVC

The huge amount of multimedia content and the variety of terminals and networks make video summarization and video adaptation two key technologies to provide effective access and browsing. With scalable video coding, the adaptation of video to heterogeneous terminals and networks can be efficiently achieved using together a layered coding hierarchy and bitstream extraction. On the other hand, many video summarization techniques can be seen as a special case of structural adaptation. This paper describes how some of them can be modified and included in the adaptation framework of the scalable extension of H.264/AVC. The advantage of this approach is that summarization and adaptation are integrated into the same efficient framework. The utility of this approach is demonstrated with experimental results for the generation of storyboards and video skims, showing that the proposed framework can generate the adapted bitstream of the summary faster than a conventional transcoding approach.

A rate-distortion optimization model for SVC inter-layer encoding and bitstream extraction

The Scalable Video Coding (SVC) standard enables viewing devices to adapt their video reception using bitstream extraction. Since SVC offers spatial, temporal, and quality combined scalability, extracting proper bitstreams for different viewing devices can be a non-trivial task, and naive choices usually produce poor playback quality. In this paper, we propose a two-prong approach to achieve rate-distortion (R-D) optimal extraction of SVC bitstreams. For SVC encoding, we developed a set of adaptation rules for setting the quantization parameters and the inter-layer dependencies among the SVC coding layers. A well-adapted SVC bitstream thus produced manifests good R-D trade-offs when its scalable layers are extracted along extraction paths consisting of successive refinement steps. For extracting R-D optimized bitstreams for different viewing devices, we formalized the notion of optimal and near-optimal extraction paths and devised computationally efficient strategies to search for the extraction paths. Experiment results demonstrated that our R-D optimized adaptation schemes and extraction strategies offer significant improvement in playback picture quality among heterogeneous viewing devices. Particularly, our adaptation rules promise R-D convexity along optimal extraction paths and permit the use of steepest-descent strategy to discover the optimal/near-optimal paths. This simple search strategy performs only half of the computation necessary for an exhaustive search.

Design options and comparison of in-network H.264/SVC adaptation

This paper explores design options and evaluates implementations of in-network, RTP/RTSP based adaptation MANEs (Media Aware Network Elements) for H.264/SVC content streaming. The obvious technique to be employed by such an adaptation MANE is to perform SVC specific bitstream extraction or truncation. Another mechanism that can be used is description (metadata) driven, coding format independent adaptation based on generic Bitstream Syntax Descriptions (gBSD), as specified within MPEG-21 Digital Item Adaptation (DIA). Adaptation MANE architectures for both approaches are developed and presented, implemented in end-to-end streaming/adaptation prototype systems, and experimentally evaluated and compared. For the gBSD based solution, open issues like the granularity of bitstream descriptions and of bitstream adaptation, metadata overhead, metadata packetization and transport options, and error resilience in case of metadata losses, are addressed. The experimental results indicate that a simple SVC specific adaptation MANE does clearly outperform the gBSD based adaptation variants. Yet, the conceptual advantages of the description driven approach, like coding format independence and flexibility, may outweigh the performance drawbacks in specific applications.

A comparison between SVC and transcoding

This paper presents a comparison between the scalable extension of H.264/AVC (SVC) and transcoding, in terms of rate-distortion (RD) performance and computational complexity. Both bitrate and spatial resolution reduction cases are included. Simulation results show that, in the aspect of RD performance, SVC performs significantly better in bitrate reduction and slightly better in spatial resolution reduction. Meanwhile, SVC adaptation through bitstream extraction has negligible complexity compared with transcoding.