Topic
Video quality
About: Video quality is a research topic. Over the lifetime, 13143 publications have been published within this topic receiving 178307 citations.
Papers published on a yearly basis
Papers
More filters
01 Aug 1998
TL;DR: In this paper, the authors proposed a watermarking technique for MPEG-2 video coding system by extending the direct sequence spread spectrum to control the strength and area of embedding with respect to the global and local characteristics of the video sequences.
Abstract: Digital watermarking is the technique which embeds an invisible signal including owner identification and copy control information into multimedia data such as audio, video, images, for copyright protection. This paper proposes a new watermarking technique which is appropriate for the MPEG-2 video coding system by extending the direct sequence spread spectrum. The proposed watermarking scheme in this paper minimizes the perceptual degradation of video quality, caused by the embedded watermark through controlling the strength and area of embedding with respect to the global and local characteristics of the video sequences. And this technique can also directly extract the embedded watermark from the watermarked MPEG-2 compressed video stream without using original video sequences. Simulation results show that the proposed scheme is robust to various attacks to remove the embedded watermark and is feasible for real time system implementation.
113 citations
TL;DR: It is argued that a rate control scheme has to balance both issues of consistent video quality on the encoder side and bitstream smoothness for the SMG on the network side and the effectiveness of the proposed algorithm is shown.
Abstract: Rate control is considered an important issue in video coding, since it significantly affects video quality. We discuss joint encoder and channel rate control for variable bit-rate (VBR) video over packet-switched ATM networks. Since variable bit-rate traffic is allowed in such networks, an open-loop encoder without rate control can generate consistent quality video. However, in order to improve the statistical multiplexing gain (SMG), an encoder buffer is essential to meet traffic constraints imposed by networks and to smooth the highly variable video bitstream. Due to the finite buffer size, some forms of encoder rate control have to be enforced, and consequently, video quality varies. We argue that a rate control scheme has to balance both issues of consistent video quality on the encoder side and bitstream smoothness for the SMG on the network side. We present a joint encoder and channel rate control algorithm for ATM networks with leaky buckets as open-loop source flow control models. The algorithm considers constraints imposed by the encoder and decoder buffers, the leaky bucket control, traffic smoothing, and rate control. The encoder rate control is separated into a sustainable-rate control and a unidirectional instantaneous-rate control. It can improve the problem of leaky bucket saturation exhibited in previous works. Experimental results with MPEG video are presented. The results verify our analysis and show the effectiveness of the proposed algorithm.
113 citations
07 May 2001
TL;DR: A method for DCT-domain blind measurement of blocking artifacts by constituting a new block across any two adjacent blocks, the blocking artifact is modeled as a 2-D step function.
Abstract: A method for DCT-domain blind measurement of blocking artifacts is proposed. By constituting a new block across any two adjacent blocks, the blocking artifact is modeled as a 2-D step function. A fast DCT-domain algorithm has been derived to constitute the new block and extract all parameters needed. Then an human visual system (HVS) based measurement of blocking artifacts is conducted. Experimental results have shown the effectiveness and stability of our method. The proposed technique can be used for online image/video quality monitoring and control in applications of DCT-domain image/video processing.
112 citations
TL;DR: A comprehensive overview of recent and currently undergoing works in the field of QoE modeling for HTTP adaptive streaming is presented, as well as existing challenges and shortcomings.
Abstract: With the recent increased usage of video services, the focus has recently shifted from the traditional quality of service-based video delivery to quality of experience (QoE)-based video delivery. Over the past 15 years, many video quality assessment metrics have been proposed with the goal to predict the video quality as perceived by the end user. HTTP adaptive streaming (HAS) has recently gained much attention and is currently used by the majority of video streaming services, such as Netflix and YouTube. HAS, using reliable transport protocols, such as TCP, does not suffer from image artifacts due to packet losses, which are common in traditional streaming technologies. Hence, the QoE models developed for other streaming technologies alone are not sufficient. Recently, many works have focused on developing QoE models targeting HAS-based applications. Also, the recently published ITU-T Recommendation series P.1203 proposes a parametric bitstream-based model for the quality assessment of progressive download and adaptive audiovisual streaming services over a reliable transport. The main contribution of this paper is to present a comprehensive overview of recent and currently undergoing works in the field of QoE modeling for HAS. The HAS QoE models, influence factors, and subjective test methodologies are discussed, as well as existing challenges and shortcomings. The survey can serve as a guideline for researchers interested in QoE modeling for HAS and also discusses possible future work.
112 citations
TL;DR: The challenges of realizing video streaming over MANETs are identified, and the proposed techniques are analyzed and classify, indicating that the research domain suffers from a problem of comparability.
Abstract: Developments in mobile devices and wireless networking provide the technical platform for video streaming over mobile ad hoc networks (MANETs) However, efforts to realize video streaming over MANETs have met many challenges, which are addressed by several different techniques Examples include cross-layer optimization, caching and replication, and packet prioritization Cross-layer optimization typically leverages multiple description video coding and multipath routing to provide the receiver(s) sufficient video quality Caching and replication add tolerance to disruptions and partitioning In this paper, we identify the challenges of realizing video streaming over MANETs, and analyze and classify the proposed techniques Since 65 % of the identified involve cross-layering design, we study the distribution of joint optimization and parameter exchanges Due to the importance and complexity of evaluating the techniques, we analyze the common methods, indicating that the research domain suffers from a problem of comparability
112 citations