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Widely-used Rate Control (RC) algorithms, such as those in the H.264 encoder, have certain shortcomings for time-sensitive applications such as High Definition Video Conferencing (HDVC): they either respond too slowly to available bandwidth variations, causing degradation in the perceived quality of the video session, or do not optimize video quality for a given available bandwidth. To overcome these...
Given the significant industrial growth of demand for virtual reality (VR), 360º video streaming is one of the most important VR applications that require cost-optimal solutions to achieve widespread proliferation of VR technology. Because of its inherent variability of data-intensive content types and its tiled-based encoding and streaming, 360º video requires new encoding ladders in adaptive streaming...
In this contribution we consider a communication system consisting of a cascade of a passive optical network (PON) link with on/off keying, and a short twisted pair (TP) link with discrete multitone modulation (DMT). Three coding configurations are investigated. In the first configuration (C1), the PON link and the TP link are protected by a Reed-Solomon (RS) code and trellis-coded modulation (TCM),...
This paper presents a method to extract rendering matrix on multi-channel audio signals as an object fed to Moving Picture Expert Group Spatial Audio Object Coding (MPEG SAOC) encoder. This technique allows MPEG SAOC to transmit multiple multi-channel audio objects, instead of only a single multi-channel background object as specified in MPEG SAOC standard. Listening tests show that the proposed method...
In this paper, an efficient content-based rate control scheme is proposed in the context of rate-distortion optimization for 3-D wavelet-based scalable video coding (SVC). Despite the prevalence of the conventional rate control methods in DCT-based SVC, the underlying formulation is not directly applicable to 3-D wavelet-based SVC. Performing optimal rate control with 3-D wavelet coding methods is...
Scientific simulations typically store only a small fraction of computed timesteps due to storage and I/O bandwidth limitations. Previous work has demonstrated the compressibility of floating-point volume data, but such compression often comes with a tradeoff between computational complexity and the achievable compression ratio. This work demonstrates the use of special-purpose video encoding hardware...
Virtual reality applications make use of 360-degree panoramic or omnidirectional video with high resolution and high frame rate in order to create the immersive experience to the user. The user views only a portion of the captured 360-degree scene at each time instant, hence streaming the whole omnidirectional video in highest quality is not efficient. In order to alleviate the problem of bandwidth...
Coding of signals with high amount of dense transient events, like applause, rain drops, etc., is usually a difficult task for perceptual audio coders. Especially at low bit rates, coding (and the associated coding noise) leads to smeared transients and a perceived increase in noise-like signal character. We propose a post-processing technique for coded/decoded applause-like signals which is based...
Depth videos affect the visual quality of virtual view greatly, while conventional encoders are not adapted to encode depth videos. To solve this problem, we propose, in the paper, a fault-tolerance based joint block-level bit allocation scheme for depth video coding. The scheme classifies depth blocks into two classes by the fault-tolerance, and constructs virtual view perceptual quality based rate-distortion...
R-λ rate control scheme is recommended in the High Efficiency Video Coding (HEVC) standard, which shows high accuracy of bit rate control but lower rate distortion performance. In order to minimize the distortion subject to a target bit rate, a λ domain frame-level rate control scheme for low delay coding of HEVC was proposed. Firstly, an improved parameter updating method is presented for the frame...
Currently, more and more 360-degree videos (or 360 videos for short) are being provided via the Internet. This kind of videos can render a virtual reality (VR) environment via a head-mounted display (HMD). However, understanding the quality of experience (QoE) of 360 videos is a big challenge because user experience in VR is a very complex phenomenon. In this paper, the QoE of 360 videos is considered...
Nowadays, the development of video coders is resulting in significantly increased performance. Among all coder categories, fine grain scalable video coders have the chance to show great advantage by freely extracting code-streams with different bitrates, resolutions, and frame rates from one source-coded bit file to satisfy the various requirements of subscribers in a multicast network. Based on the...
Two layer coding based on JPEG 2000 for HDR images was proposed. The proposed coding scheme, referred to as extended JPEG XT, is an extension of JPEG XT Profile A, and takes advantages as follows: freely bit rate controllability, high compression efficiency, available for over-eight-bits LDR images, and so on. In this paper, some experimental results for the quality of the reconstructed HDR images...
Unlike most researches focus on computation reduction, the fast algorithm proposed in this paper aims at maintaining the coding efficiency as high as possible. In the proposed algorithm we employ support vector machine (SVM) that uses three parameters as features: variances, low-frequency AC components of DCT and spatially neighboring CU levels for fast CU size decision. In addition, based upon RMD...
The rapid growth of the volume of multimedia data necessitates efficient compression and transmission of videos, which are requested in divergent bitrates owing to the diverse network bandwidth constraints or end device resolution/complexity requirements. Scalable video coding (SVC) is a coding paradigm that allows once-encoded video to be adapted to any desired bitrate or quality level, and thus...
Transrating is a bitrate transcoding technique that facilitates video applications in heterogeneous environments. This paper presents a fast coding-unit (CU) mode decision algorithm for transrating a once-encoded HEVC bitstreams to lower bitrate versions of diverse quality levels. The proposed method comprises three major parts. First, an early SKIP decision is based on the modes and motion vectors...
The ×265 video encoder aims at improving the speed and the computational efficiency of HEVC encoders implementation. In this paper we present a detailed energy consumption analysis, considering the consumption components of CPU, cache memories and main memory, for all ×265 presets executing in a multicore system. Ten HD 1080p test video sequences with different motion and brightness characteristics...
Multiple transforms have received considerable attention recently, especially in the course of an exploration conducted by MPEG and ITU toward the standardization of the next generation video compression algorithm. This joint team has developed a software, called the Joint Exploration Model (JEM) which outperforms by over 25% the HEVC standard. The transform step in JEM consists in Adaptive Multiple...
To meet the requirement of HEVC conversational video transmission over packet-loss network, a novel error resilient scheme based on region-of-interest (ROI) is proposed. First, the weight value for each coding block tree(CTU) in the face detection region is generated. Then, by using the ROI weight value, motion vector and mode decision method based on weighted distortion methods are developed. At...
HTTP adaptive streaming (HAS) has become the de-facto standard for video streaming to ensure continuous multimedia service delivery under irregularly changing network conditions. Many studies already investigated the detrimental impact of various playback characteristics on the Quality of Experience of end users, such as initial loading, stalling or quality variations. However, dedicated studies tackling...
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