102,512 research outputs found
Load Balancing Strategies for Slice-Based Parallel Versions of JEM Video Encoder
The proportion of video traffic on the internet is expected to reach 82% by 2022, mainly
due to the increasing number of consumers and the emergence of new video formats with more
demanding features (depth, resolution, multiview, 360, etc.). Efforts are therefore being made to
constantly improve video compression standards to minimize the necessary bandwidth while retaining high video quality levels. In this context, the Joint Collaborative Team on Video Coding has
been analyzing new video coding technologies to improve the compression efficiency with respect to
the HEVC video coding standard. A software package known as the Joint Exploration Test Model
has been proposed to implement and evaluate new video coding tools. In this work, we present
parallel versions of the JEM encoder that are particularly suited for shared memory platforms, and
can significantly reduce its huge computational complexity. The proposed parallel algorithms are
shown to achieve high levels of parallel efficiency. In particular, in the All Intra coding mode, the
best of our proposed parallel versions achieves an average efficiency value of 93.4%. They als
Median Trilateral Loop Filter for Depth Map Video Coding
Abstract-Emerging extensions to conventional stereo video technologies like 3D Video require to add depth information to 2D video data. This supplementary data needs to be coded efficiently and transmitted to the receiver where arbitrary viewpoints are generated by using this additional information. The depth maps are characterized by piecewise smooth regions, which are bounded by sharp edges describing depth discontinuities along object boundaries. Preserving these characteristics and especially depth discontinuities is a crucial requirement for depth map coding. When coding depth maps by means of a conventional hybrid video coder, ringing artifacts are introduced along the sharp edges and result in quality degradation when using the reconstructed depth maps for view synthesis. To reduce these ringing artifacts and also to better align object boundaries in video and depth data, a new in-loop filter is proposed, which reconstructs the described characteristics of depth maps
3D video coding and transmission
The capture, transmission, and display of
3D content has gained a lot of attention in the last few
years. 3D multimedia content is no longer con fined to
cinema theatres but is being transmitted using stereoscopic
video over satellite, shared on Blu-RayTMdisks,
or sent over Internet technologies. Stereoscopic displays
are needed at the receiving end and the viewer needs to
wear special glasses to present the two versions of the
video to the human vision system that then generates
the 3D illusion. To be more e ffective and improve the
immersive experience, more views are acquired from a
larger number of cameras and presented on di fferent displays,
such as autostereoscopic and light field displays.
These multiple views, combined with depth data, also
allow enhanced user experiences and new forms of interaction
with the 3D content from virtual viewpoints.
This type of audiovisual information is represented by a
huge amount of data that needs to be compressed and
transmitted over bandwidth-limited channels. Part of
the COST Action IC1105 \3D Content Creation, Coding
and Transmission over Future Media Networks" (3DConTourNet)
focuses on this research challenge.peer-reviewe
Three-dimensional video coding on mobile platforms
Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2009.Thesis (Master's) -- Bilkent University, 2009.Includes bibliographical references leaves 83-87.With the evolution of the wireless communication technologies and the multimedia
capabilities of the mobile phones, it is expected that three-dimensional
(3D) video technologies will soon get adapted to the mobile phones. This raises
the problem of choosing the best 3D video representation and the most efficient
coding method for the selected representation for mobile platforms. Since the
latest 2D video coding standard, H.264/MPEG-4 AVC, provides better coding
efficiency over its predecessors, coding methods of the most common 3D video
representations are based on this standard. Among the most common 3D video
representations, there are multi-view video, video plus depth, multi-view video
plus depth and layered depth video. For using on mobile platforms, we selected
the conventional stereo video (CSV), which is a special case of multi-view video,
since it is the simplest among the available representations. To determine the
best coding method for CSV, we compared the simulcast coding, multi-view coding
(MVC) and mixed-resolution stereoscopic coding (MRSC) without inter-view
prediction, with subjective tests using simple coding schemes. From these tests,
MVC is found to provide the best visual quality for the testbed we used, but
MRSC without inter-view prediction still came out to be promising for some of the test sequences and especially for low bit rates. Then we adapted the Joint
Video Team’s reference multi-view decoder to run on ZOOMTM OMAP34xTM
Mobile Development Kit (MDK). The first decoding performance tests on the
MDK resulted with around four stereo frames per second with frame resolutions
of 640×352. To further improve the performance, the decoder software is profiled
and the most demanding algorithms are ported to run on the embedded DSP
core. Tests resulted with performance gains ranging from 25% to 60% on the
DSP core. However, due to the design of the hardware platform and the structure
of the reference decoder, the time spent for the communication link between
the main processing unit and the DSP core is found to be high, leaving the performance
gains insignificant. For this reason, it is concluded that the reference
decoder should be restructured to use this communication link as infrequently
as possible in order to achieve overall performance gains by using the DSP core.Bal, CanM.S
Multiple description video coding for stereoscopic 3D
In this paper, we propose an MDC schemes for stereoscopic 3D video. In the literature, MDC has previously been applied in 2D video but not so much in 3D video. The proposed algorithm enhances the error resilience of the 3D video using the combination of even and odd frame based MDC while retaining good temporal prediction efficiency for video over error-prone networks. Improvements are made to the original even and odd frame MDC scheme by adding a controllable amount of side information to improve frame interpolation at the decoder. The side information is also sent according to the video sequence motion for further improvement. The performance of the proposed algorithms is evaluated in error free and error prone environments especially for wireless channels. Simulation results show improved performance using the proposed MDC at high error rates compared to the single description coding (SDC) and the original even and odd frame MDC
Depth map compression via 3D region-based representation
In 3D video, view synthesis is used to create new virtual views between
encoded camera views. Errors in the coding of the depth maps introduce
geometry inconsistencies in synthesized views. In this paper, a new 3D plane
representation of the scene is presented which improves the performance of
current standard video codecs in the view synthesis domain. Two image segmentation
algorithms are proposed for generating a color and depth segmentation.
Using both partitions, depth maps are segmented into regions without
sharp discontinuities without having to explicitly signal all depth edges. The
resulting regions are represented using a planar model in the 3D world scene.
This 3D representation allows an efficient encoding while preserving the 3D
characteristics of the scene. The 3D planes open up the possibility to code
multiview images with a unique representation.Postprint (author's final draft
Three-dimensional media for mobile devices
Cataloged from PDF version of article.This paper aims at providing an overview of the core technologies enabling the delivery of 3-D Media to next-generation mobile devices. To succeed in the design of the corresponding system, a profound knowledge about the human visual system and the visual cues that form the perception of depth, combined with understanding of the user requirements for designing user experience for mobile 3-D media, are required. These aspects are addressed first and related with the critical parts of the generic system within a novel user-centered research framework. Next-generation mobile devices are characterized through their portable 3-D displays, as those are considered critical for enabling a genuine 3-D experience on mobiles. Quality of 3-D content is emphasized as the most important factor for the adoption of the new technology. Quality is characterized through the most typical, 3-D-specific visual artifacts on portable 3-D displays and through subjective tests addressing the acceptance and satisfaction of different 3-D video representation, coding, and transmission methods. An emphasis is put on 3-D video broadcast over digital video broadcasting-handheld (DVB-H) in order to illustrate the importance of the joint source-channel optimization of 3-D video for its efficient compression and robust transmission over error-prone channels. The comparative results obtained identify the best coding and transmission approaches and enlighten the interaction between video quality and depth perception along with the influence of the context of media use. Finally, the paper speculates on the role and place of 3-D multimedia mobile devices in the future internet continuum involving the users in cocreation and refining of rich 3-D media content
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