The Experts below are selected from a list of 30897 Experts worldwide ranked by ideXlab platform
Ebroul Izquierdo - One of the best experts on this subject based on the ideXlab platform.
-
lagrange multiplier selection in wavelet based scalable video coding for Quality Scalability
Signal Processing-image Communication, 2009Co-Authors: Shuai Wan, Fuzheng Yang, Ebroul IzquierdoAbstract:In this paper, a method for Lagrange multiplier selection is proposed in the context of rate-distortion optimisation for wavelet-based scalable video coding targeting Quality Scalability. Despite the prevalence of the conventional method for Lagrange multiplier selection in hybrid video coding, the underlying formulation is not applicable to wavelet-based scalable video coding. To address the inherent challenges, a thorough analysis of the rate-distortion models for transform video coding is provided with regard to low and middle-to-high bit-rates, respectively. Based on the analysis, the models are consolidated according to experimental observations and the consolidated rate-distortion models serve as the basis for the derivation of the Lagrange multiplier. Considering the influence of the open-loop prediction structure on the rate-distortion performance, the Lagrange multiplier is initially derived for a single-targeted bit-rate. Moreover, the method for Lagrange multiplier selection in scalable video coding aiming at multiple-targeted bit-rates is proposed in a general sense of bit-rate range, varying from low to high bit-rates, building on the initially derived Lagrange multiplier for a single-targeted bit-rate. The proposed Lagrange multiplier is content adaptive and well suited for wavelet-based scalable video coding where quantisation steps are unavailable. Detailed performance evaluation of the proposed method for wavelet-based scalable video coding is provided with regard to a given targeted bit-rate and multiple-targeted bit-rates, respectively. The experimental results have demonstrated the effectiveness of the proposed Lagrange multiplier for rate-distortion optimisation considering Quality Scalability in wavelet-based scalable video coding.
Lina J Karam - One of the best experts on this subject based on the ideXlab platform.
-
h 264 coarse grain scalable cgs and medium grain scalable mgs encoded video a trace based traffic and Quality evaluation
IEEE Transactions on Broadcasting, 2012Co-Authors: Rohan Gupta, Akshay Pulipaka, Patrick Seeling, Lina J Karam, Martin ReissleinAbstract:The scalable video coding (SVC) extension of the H.264/AVC video coding standard provides two mechanisms, namely coarse grain Scalability (CGS) and medium grain Scalability (MGS), for Quality scalable video encoding, which varies the fidelity (signal-to-noise ratio) of the encoded video stream. As H.264/AVC and its SVC extension are expected to become widely adopted for the network transport of video, it is important to thoroughly study their network traffic characteristics, including the bit rate variability. In this paper, we report on a large-scale study of the rate-distortion (RD) and rate variability-distortion (VD) characteristics of CGS and MGS. We found that CGS achieves low bit rate overheads in the 10–30% range compared to H.264 SVC single-layer encodings only for encodings with a total of up to three Quality levels; more Quality levels result in substantially higher overheads. The traffic variabilities of CGS are generally lower than for single-layer streams. We found that in the low to mid range of the MGS Quality Scalability, MGS can achieve the same or even slightly higher RD efficiency than corresponding single-layer encoding; toward the upper end of the MGS Quality Scalability range the RD efficiency drops off significantly. MGS layer extraction following the hierarchical B frame structure gives nearly as high RD performance as RD-optimized extraction. In the range of high RD efficiency, MGS streams have significantly higher traffic variabilities than single-layer streams at the frame time scale. At the group-of-pictures (GoP) time scale, MGS has similar or lower levels of traffic variability compared to single-layer streams. Generally, MGS layer extraction over the time horizon of individual GoPs gives significantly lower traffic variability than extraction over the time horizon of the full video sequence.
-
Overview and Traffic Characterization of Coarse-Grain Quality Scalable (CGS) H.264 SVC Encoded Video
2010 7th IEEE Consumer Communications and Networking Conference, 2010Co-Authors: Akshay Pulipaka, Patrick Seeling, Martin Reisslein, Lina J KaramAbstract:The scalable video coding extension (SVC) of the H.264/AVC standard is widely considered for IPTV. SVC supports a variety of Scalability modes, including temporal, spatial as well as coarse-grain and medium-grain Quality scalabilities. In this paper, we first give an overview of coarse-grain Quality Scalability (CGS). We generate traces of CGS encodings of long CIF resolution video sequences; the traces provide a simple yet effective characterization of CGS encoded video for performance evaluation of video transport systems, including IPTV systems. We conduct a detailed statistical analysis of the CGS video traces. We compare the bit rate-distortion (RD) and the bit rate variability-distortion (VD) performances of scalable CGS encodings with those of non-scalable SVC single layer encodings. We thus quantify the tradeoff between the rate adaptability afforded by CGS encoding and the cost in terms of RD efficiency compared to non-scalable single-layer video.
-
traffic and Quality characterization of the h 264 avc scalable video coding extension
Advances in Multimedia, 2008Co-Authors: Geert Van Der Auwera, Martin Reisslein, Prasanth T David, Lina J KaramAbstract:The recent scalable video coding (SVC) extension to the H.264/AVC video coding standard has unprecedented compression efficiency while supporting a wide range of Scalability modes, including temporal, spatial, and Quality (SNR) Scalability, as well as combined spatiotemporal SNR Scalability. The traffic characteristics, especially the bit rate variabilities, of the individual layer streams critically affect their network transport. We study the SVC traffic statistics, including the bit rate distortion and bit rate variability distortion, with long CIF resolution video sequences and compare them with the corresponding MPEG-4 Part 2 traffic statistics. We consider (i) temporal Scalability with three temporal layers, (ii) spatial Scalability with a QCIF base layer and a CIF enhancement layer, as well as (iii) Quality Scalability modes FGS and MGS. We find that the significant improvement in RD efficiency of SVC is accompanied by substantially higher traffic variabilities as compared to the equivalent MPEG-4 Part 2 streams. We find that separately analyzing the traffic of temporal-Scalability only encodings gives reasonable estimates of the traffic statistics of the temporal layers embedded in combined spatiotemporal encodings and in the base layer of combined FGS-temporal encodings. Overall, we find that SVC achieves significantly higher compression ratios than MPEG-4 Part 2, but produces unprecedented levels of traffic variability, thus presenting new challenges for the network transport of scalable video.
Hsuehming Hang - One of the best experts on this subject based on the ideXlab platform.
-
Fast Context-Adaptive Mode Decision Algorithm for Scalable Video Coding With Combined Coarse-Grain Quality Scalability (CGS) and Temporal Scalability
IEEE Transactions on Circuits and Systems for Video Technology, 2010Co-Authors: Wenhsiao Peng, Hsuehming HangAbstract:To speed up the H.264/MPEG scalable video coding (SVC) encoder, we propose a layer-adaptive intra/inter mode decision algorithm and a motion search scheme for the hierarchical B-frames in SVC with combined coarse-grain Quality Scalability (CGS) and temporal Scalability. To reduce computation but maintain the same level of coding efficiency, we examine the rate-distortion (R-D) performance contributed by different coding modes at the enhancement layers (EL) and the mode conditional probabilities at different temporal layers. For the intra prediction on inter frames, we can reduce the number of Intra4×4/Intra 8×8 prediction modes by 50% or more, based on the reference/base layer intra prediction directions. For the EL inter prediction, the look-up tables containing inter prediction candidate modes are designed to use the macroblock (MB) coding mode dependence and the reference/base layer quantization parameters (Qp). In addition, to avoid checking all motion estimation (ME) reference frames, the base layer (BL) reference frame index is selectively reused. And according to the EL MB partition, the BL motion vector can be used as the initial search point for the EL ME. Compared with Joint Scalable Video Model 9.11, our proposed algorithm provides a 20× speedup on encoding the EL and an 85% time saving on the entire encoding process with negligible loss in coding efficiency. Moreover, compared with other fast mode decision algorithms, our scheme can demonstrate a 7-41% complexity reduction on the overall encoding process.
-
fast context adaptive mode decision algorithm for scalable video coding with combined coarse grain Quality Scalability cgs
2010Co-Authors: Hungchih Lin, Wenhsiao Peng, Hsuehming HangAbstract:To speed up the H.264/MPEG scalable video coding (SVC) encoder, we propose a layer-adaptive intra/inter mode de- cision algorithm and a motion search scheme for the hierarchical B-frames in SVC with combined coarse-grain Quality Scalability (CGS) and temporal Scalability. To reduce computation but maintain the same level of coding efficiency, we examine the rate- distortion (R-D) performance contributed by different coding modes at the enhancement layers (EL) and the mode conditional probabilities at different temporal layers. For the intra prediction on inter frames, we can reduce the number of Intra4×4/Intra8×8 prediction modes by 50% or more, based on the reference/base layer intra prediction directions. For the EL inter prediction, the look-up tables containing inter prediction candidate modes are designed to use the macroblock (MB) coding mode de- pendence and the reference/base layer quantization parameters (Qp). In addition, to avoid checking all motion estimation (ME) reference frames, the base layer (BL) reference frame index is selectively reused. And according to the EL MB partition, the BL motion vector can be used as the initial search point for the EL ME. Compared with Joint Scalable Video Model 9.11, our proposed algorithm provides a 20× speedup on encoding the EL and an 85% time saving on the entire encoding process with negligible loss in coding efficiency. Moreover, compared with other fast mode decision algorithms, our scheme can demonstrate a 7-41% complexity reduction on the overall encoding process. Index Terms—Coarse-grain Quality Scalability, encoder opti- mization, fast mode decision, scalable video coding (SVC).
Shuai Wan - One of the best experts on this subject based on the ideXlab platform.
-
lagrange multiplier selection in wavelet based scalable video coding for Quality Scalability
Signal Processing-image Communication, 2009Co-Authors: Shuai Wan, Fuzheng Yang, Ebroul IzquierdoAbstract:In this paper, a method for Lagrange multiplier selection is proposed in the context of rate-distortion optimisation for wavelet-based scalable video coding targeting Quality Scalability. Despite the prevalence of the conventional method for Lagrange multiplier selection in hybrid video coding, the underlying formulation is not applicable to wavelet-based scalable video coding. To address the inherent challenges, a thorough analysis of the rate-distortion models for transform video coding is provided with regard to low and middle-to-high bit-rates, respectively. Based on the analysis, the models are consolidated according to experimental observations and the consolidated rate-distortion models serve as the basis for the derivation of the Lagrange multiplier. Considering the influence of the open-loop prediction structure on the rate-distortion performance, the Lagrange multiplier is initially derived for a single-targeted bit-rate. Moreover, the method for Lagrange multiplier selection in scalable video coding aiming at multiple-targeted bit-rates is proposed in a general sense of bit-rate range, varying from low to high bit-rates, building on the initially derived Lagrange multiplier for a single-targeted bit-rate. The proposed Lagrange multiplier is content adaptive and well suited for wavelet-based scalable video coding where quantisation steps are unavailable. Detailed performance evaluation of the proposed method for wavelet-based scalable video coding is provided with regard to a given targeted bit-rate and multiple-targeted bit-rates, respectively. The experimental results have demonstrated the effectiveness of the proposed Lagrange multiplier for rate-distortion optimisation considering Quality Scalability in wavelet-based scalable video coding.
Thomas Wiegand - One of the best experts on this subject based on the ideXlab platform.
-
hd video broadcasting using scalable video coding combined with dvb s2 variable coding and modulation
2010 5th Advanced Satellite Multimedia Systems Conference and the 11th Signal Processing for Space Communications Workshop, 2010Co-Authors: S Mirta, Pablo Iñigo, C Leguern, L. Guarnieri, Thomas Schierl, Thomas Wiegand, Jérôme TroncAbstract:The Scalable Video Coding (SVC) is an extension of H.264/AVC offering temporal, spatial, and Quality Scalability. Compared to the non-scalable profile of H.264/AVC, SVC allows layered transmission of video data. Variable Coding and Modulation (VCM) based DVB-S2 Video Broadcasting Systems enables effective selection of modulation modes and FEC coderates offering differentiated error protection. In this work the usage of SVC with the DVB-S2 VCM mode has been investigated.
-
mobile video transmission using scalable video coding
IEEE Transactions on Circuits and Systems for Video Technology, 2007Co-Authors: Thomas Schierl, Thomas Stockhammer, Thomas WiegandAbstract:The scalable video coding (SVC) standard as an extension of H.264/AVC allows efficient, standard-based temporal, spatial, and Quality Scalability of video bit streams. Scalability of a video bit stream allows for media bit rate as well as for device capability adaptation. Moreover, adaptation of the bit rate of a video signal is a desirable key feature, if limitation in network resources, mostly characterized by throughput variations, varying delay or transmission errors, need to be considered. Typically, in mobile networks the throughput, delay and errors of a connection (link) depend on the current reception conditions, which are largely influenced by a number of physical factors. In order to cope with the typically varying characteristics of mobile communication channels in unicast, multicast, or broadcast services, different methods for increasing robustness and achieving Quality of service are desirable. We will give an overview of SVC and its relation to mobile delivery methods. Furthermore, innovative use cases are introduced which apply SVC in mobile networks.
-
overview of the scalable video coding extension of the h 264 avc standard
IEEE Transactions on Circuits and Systems for Video Technology, 2007Co-Authors: Heiko Schwarz, Detlev Marpe, Thomas WiegandAbstract:With the introduction of the H.264/AVC video coding standard, significant improvements have recently been demonstrated in video compression capability. The Joint Video Team of the ITU-T VCEG and the ISO/IEC MPEG has now also standardized a Scalable Video Coding (SVC) extension of the H.264/AVC standard. SVC enables the transmission and decoding of partial bit streams to provide video services with lower temporal or spatial resolutions or reduced fidelity while retaining a reconstruction Quality that is high relative to the rate of the partial bit streams. Hence, SVC provides functionalities such as graceful degradation in lossy transmission environments as well as bit rate, format, and power adaptation. These functionalities provide enhancements to transmission and storage applications. SVC has achieved significant improvements in coding efficiency with an increased degree of supported Scalability relative to the scalable profiles of prior video coding standards. This paper provides an overview of the basic concepts for extending H.264/AVC towards SVC. Moreover, the basic tools for providing temporal, spatial, and Quality Scalability are described in detail and experimentally analyzed regarding their efficiency and complexity.
