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ICIP'13 (Melbourne, Australia, 2013), Proc., to appear.; 01/2013
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ABSTRACT: Quadtree-based block partitioning together with motion-compensated prediction has proven to be an efficient approach in video compression. However, when dealing with spatially neighboring blocks in uniformly displaced regions, quadtree-based partitioning may lead to redundant sets of transmitted motion parameters. This paper proposes and describes a simple but efficient block merging algorithm that aims at removing those redundancies by using only a single parameter set for a whole motion-compensated region of contiguous blocks. Simulation results show that our proposed merging technique works more efficiently than the conceptually similar direct mode as, e.g., specified in H.264/AVC. Due its efficiency and simplicity, our proposed merging approach has been adopted into the first test model of the high efficiency video coding (HEVC) standardization project, as currently pursued by ITU-T VCEG and ISO/IEC MPEG.
Multimedia and Expo (ICME), 2011 IEEE International Conference on; 08/2011
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D. Marpe,
H. Schwarz,
S. Bosse,
B. Bross,
P. Helle,
T. Hinz,
H. Kirchhoffer,
H. Lakshman,
Tung Nguyen,
S. Oudin,
M. Siekmann,
K. Sühring,
M. Winken,
T. Wiegand
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ABSTRACT: This paper describes a novel video coding scheme that can be considered as a generalization of the block-based hybrid video coding approach of H.264/AVC. While the individual building blocks of our approach are kept simple similarly as in H.264/AVC, the flexibility of the block partitioning for prediction and transform coding has been substantially increased. This is achieved by the use of nested and pre-configurable quadtree structures, such that the block partitioning for temporal and spatial prediction as well as the space-frequency resolution of the corresponding prediction residual can be adapted to the given video signal in a highly flexible way. In addition, techniques for an improved motion representation as well as a novel entropy coding concept are included. The presented video codec was submitted to a Call for Proposals of ITU-T VCEG and ISO/IEC MPEG and was ranked among the five best performing proposals, both in terms of subjective and objective quality.
Picture Coding Symposium (PCS), 2010; 01/2011
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ABSTRACT: It is a well-known fact that, in order to overcome annoying blocking artifacts, transforms with block-overlapping basis functions have been proposed for image coding. Typically in transform coding, the encoder determines the transform coefficient values by applying the forward transform followed by scalar quantization. In this paper we present an approach, how rate-distortion optimized Lapped Biorthogonal Transform (LBT) coefficient values can be determined by solving ℓ<sub>1</sub>-regularized least squares problems. We compare a global version, where all the transform coefficients are obtained in one single optimization step, and a local version, where the optimization is done separately for each block, which results in losing optimality, but achieving highly reduced complexity. Our simulation results show gains of about 0.5 dB PSNR compared to ordinary forward transform and scalar quantization with only small losses (<; 0.1 dB) for the local variant.
Image Processing (ICIP), 2010 17th IEEE International Conference on; 10/2010
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ABSTRACT: In this paper, we describe and analyze a low complexity scalable video codec that extends our H.264-implementation DAVC. We can show that DSVC, our temporally scaled codec, attains an RD performance identical to the non-scaled version at comparable configuration. We achieve this by QP cascading, a method of assigning gradual refining quantization parameters to the declining temporal layers. The different quantization of frames does not lead to visual distinguishable quality fluctuations. This video codec is the core component of a software-based multipoint videoconference system, which works without MCU on a hybrid P2P network structure.
Consumer Electronics (ISCE), 2010 IEEE 14th International Symposium on; 07/2010
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ABSTRACT: In this paper we present a multipoint media conference software with extended network capabilities. Its core components combine an advanced, highly efficient H.264/AVC video coding system. Session signaling follows the SIP standard and simultaneously supports IPv4 and IPv6. Built upon an underlying peer-to-peer communication scheme, it further supports advanced integration with legacy MCUs and thereby enables hybrid sessions that extend into the H.323 world. We demonstrate how our software can span fully functional conferences across these worlds by deploying a passive gateway peer. Finally, we address security issues arising in distributed conferencing systems. It is shown, how the use of cryptographically generated identifiers enables the application to authenticate data on a packet level, thereby preventing abuse and impersonation of the conference overlay network.
Consumer Electronics, 2009. ISCE '09. IEEE 13th International Symposium on; 06/2009
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ABSTRACT: For compression of 3-D dynamic meshes, the novel framework of so-called frame-based animated mesh compression (FAMC) has been introduced recently. In this context, we propose an efficient scheme for representation and statistical coding which is conceptually based on our previous work on context-based adaptive binary arithmetic coding (CABAC). After reviewing the basic principles of both CABAC and FAMC, we present suitable modifications and adaptations of both concepts in order to build an integrated solution with a high degree of coding efficiency. To this end, particular focus of our study has been put on the design of appropriate binarization and context modeling schemes. In our experiments, we obtained average bit-rate savings of more than 30% for a typical test set of dynamic meshes, when comparing the final design of our CABAC enriched FAMC scheme to the original version of FAMC using a conventional N-ary arithmetic coder. Our integrated approach has been adopted recently as part of the MPEG-4 Animated Framework extension (AFX).
Image Processing, 2008. ICIP 2008. 15th IEEE International Conference on; 11/2008
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ABSTRACT: A rapidly growing number of carriers offer wireless video services to their customers, taking advantage of high quality video codecs implemented in dedicated hardware of selected mobile devices. In this paper we introduce a video conferencing software, which seamlessly integrates mobile with stationary users in a provider and device independent fashion. Innovations of this work are twofold. At first we report on a mobile realization of an H.264 video codec and its performance on a standard consumer Smartphone. Operating within the tight bounds of real-time compliance on mobiles, this software is an adapted version of a highly optimized H.264 codec. This DAVC codec, which we introduce along the line, significantly out-performs compatible H.264 realizations and allows for a scalable adaptation of its frame rate. In the second part we present a barrier-resistant peer-to-peer group communication scheme, which scales well for medium-size conferences and accounts for the heterogeneous nature of mobile and stationary participants. An outlook on mobility related group communication issues and future optimizations based on structured communication layers concludes the work.
World of Wireless, Mobile and Multimedia Networks, 2008. WoWMoM 2008. 2008 International Symposium on a; 07/2008
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ABSTRACT: This paper presents a new compression technique for 3D dynamic meshes, referred to as FAMC - Frame-based Animated Mesh Compression, recently promoted within the MPEG-4 standard as Amen-dement 2 of part 16 (AFX -Animation Framework extension). The FAMC approach combines a model-based motion-compensation strategy with transform/predictive coding of residual errors. First, a skinning motion-compensation model is automatically derived from a frame-based representation. Subsequently, either 1) DCT/lifting wavelets or 2) layer-based predictive coding is employed to exploit remaining spatio-temporal correlations in the residual signal. Both motion model parameters and residual signal components are finally encoded by using context-based adaptive binary arithmetic coding (CABAC). The proposed FAMC encoder offers high compression performance with gains of 60% in terms of bit-rate savings relative to previous MPEG-4 technology and of 20% to 40% relative to state-of-the-art techniques. FAMC is well suited for compressing both geometric and photometric (normal vectors, colors...) attributes. In addition, FAMC also supports a rich set of functionalities including streaming, scalability (spatial, temporal and quality) and progressive transmission.
3DTV Conference: The True Vision - Capture, Transmission and Display of 3D Video, 2008; 06/2008
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ABSTRACT: 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.
IEEE Transactions on Circuits and Systems for Video Technology 10/2007; · 1.65 Impact Factor
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ABSTRACT: Block-based video-coding for 4:4:4 color sampling is extended by an adaptive color space transform. The presented technique enables an encoder to switch between several given color space representations in order to optimize rate-distortion performance. Simulations based on the current draft of the H.264/MPEG4-AVC 4:4:4 extensions demonstrate that our technique provides a rate-distortion performance equal or better than that obtained when using any of the individual color spaces only
Image Processing, 2006 IEEE International Conference on; 11/2006
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ABSTRACT: The scalable extension of H.264/MPEG4-AVC is a current standardization project of the joint video team of the ITU-T Video Coding Experts Group and the ISO/IEC moving picture experts group. This paper gives an overview of the design of the scalable H.264/MPEG4-AVC extension and describes the basic concepts for supporting temporal, spatial, and SNR scalability. The efficiency of the described concepts for providing spatial and SNR scalability is analyzed by means of simulation results and compared to H.264/MPEG4-AVC compliant single layer coding
Image Processing, 2006 IEEE International Conference on; 11/2006
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ABSTRACT: H.264/MPEG4-AVC is the latest video coding standard of the ITU-T video coding experts group (VCEG) and the ISO/IEC moving picture experts group (MPEG). H.264/MPEG4-AVC has recently become the most widely accepted video coding standard since the deployment of MPEG2 at the dawn of digital television, and it may soon overtake MPEG2 in common use. It covers all common video applications ranging from mobile services and videoconferencing to IPTV, HDTV, and HD video storage. This article discusses the technology behind the new H.264/MPEG4-AVC standard, focusing on the main distinct features of its core coding technology and its first set of extensions, known as the fidelity range extensions (FRExt). In addition, this article also discusses the current status of adoption and deployment of the new standard in various application areas
IEEE Communications Magazine 09/2006; · 3.79 Impact Factor
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ABSTRACT: The scalability extension of H.264/AVC uses an oversampled pyramid representation for spatial scalability, where for each spatial resolution a separate motion compensation or MCTF loop is deployed. When the reconstructed signal at a lower resolution is used to predict the next higher resolution, the motion compensation or MCTF loops including the deblocking filter operations of both resolutions have to be executed. This imposes a large complexity burden on the decoding of the higher resolution signals, especially when multiple spatial layers are utilized. In this paper, we investigate the approach to only allow prediction between spatial layers for parts of the lower resolution pictures that are intra-coded in order to avoid decoding that requires multiple motion compensation or MCTF loops. Experimental results evaluate the effectiveness of the proposed approach.
Image Processing, 2005. ICIP 2005. IEEE International Conference on; 10/2005
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ABSTRACT: The technical work on the first amendment of the H.264/MPEG4-AVC video coding standard has recently been completed. In these so-called fidelity range extensions (FRExt) a set of new coding tools is specified which is primarily targeted at providing significant improvements in coding efficiency for higher-fidelity video material. This paper presents an overview of the corresponding methods, briefly discusses some important aspects regarding profiles and applications, and finally provides experimental results for a performance comparison with existing coding technology.
Image Processing, 2005. ICIP 2005. IEEE International Conference on; 10/2005
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ABSTRACT: The scalability extension of H.264/AVC (H. Schwarz, et al., 2004) uses a layered approach for providing spatial, temporal, and SNR scalability. Due to this concept, only a restricted set of spatio-temporal-SNR points can be extracted and decoded from a global scalable bit-stream, and this set of points is defined by the chosen encoder configuration. In this paper, we present a new approach for providing flexible combined spatial, temporal, and SNR scalability. The increased flexibility is achieved by introducing NAL units that represent a refinement signal for a picture in a coarse-to-fine-description and can be truncated at any arbitrary point. The simulation results show that this approach is capable of providing flexible combined scalability while the coding efficiency is only slightly worse than that of the layered approach.
Multimedia and Expo, 2005. ICME 2005. IEEE International Conference on; 08/2005
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ABSTRACT: We present an SNR-scalable extension of the H.264/AVC video coding standard. To achieve an efficient SNR-scalable bit-stream representation of a video sequence, the temporal dependencies between pictures are exploited by using an open-loop subband approach. The related temporal analysis-synthesis filter bank structure is generalized to facilitate an adaptive block-based choice between the motion-compensated lifting representations of the Haar filter (uni-directional prediction) and the 5/3 filter (bi-directional prediction), both coupled with multiple-reference frame capabilities. As a remarkable feature of our approach, most components of H.264/AVC are used as specified in the standard, while only a few have been adjusted to the motion-compensated temporal filtering structure. Our proposed SNR-scalable extension was tested for a set of CIF sequences, and the results indicate that a coding efficiency comparable to that of the state-of-the-art H.264/AVC standard can be achieved.
Image Processing, 2004. ICIP '04. 2004 International Conference on; 11/2004
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ABSTRACT: H.264/AVC, the result of the collaboration between the ISO/IEC Moving Picture Experts Group and the ITU-T Video Coding Experts Group, is the latest standard for video coding. The goals of this standardization effort were enhanced compression efficiency, network friendly video representation for interactive (video telephony) and non-interactive applications (broadcast, streaming, storage, video on demand). H.264/AVC provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards. Compared to previous standards, the decoder complexity is about four times that of MPEG-2 and two times that of MPEG-4 Visual Simple Profile. This paper provides an overview of the new tools, features and complexity of H.264/AVC.
IEEE Circuits and Systems Magazine 09/2004; · 1.44 Impact Factor
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ABSTRACT: A new algorithm for context modeling of binary sources with application to video compression is presented. Our proposed method is based on a tree rearrangement and tree selection process for an optimized modeling of binary context trees. We demonstrate its use for adaptive context-based coding of selected syntax elements in a video coder. For that purpose we apply our proposed technique to the H.264/AVC standard and evaluate its performance for different sources and different quantization parameters. Experimental results show that by using our proposed algorithm coding gains similar or superior to those obtained with the H.264/AVC CABAC algorithm is achieved.
Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on; 10/2003
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ABSTRACT: A novel and highly efficient algorithm of multiplication-free binary arithmetic coding is proposed. Our proposed method relies on simple table lookups for performing the computationally critical operations of interval subdivision and probability estimation. Moreover, the underlying design principle provides a great flexibility for serving the different needs of all kind of coding applications where binary or binarized data have to be processed. A binary arithmetic coder of the type described in this paper has become part of the CABAC entropy coding scheme of the emerging H.264/AVC video coding standard. Experiments using this binary arithmetic coder in its native video coding environment demonstrate a superior coding efficiency as well as a significantly higher throughput rate in comparison to the MQ coder, which is currently being considered state-of-the-art in fast binary arithmetic coding.
Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on; 10/2003
