Video quality

About: Video quality is a research topic. Over the lifetime, 13143 publications have been published within this topic receiving 178307 citations.

No-Reference Video Quality Assessment Based on Artifact Measurement and Statistical Analysis

Abstract: A discrete cosine transform (DCT)-based no-reference video quality prediction model is proposed that measures artifacts and analyzes the statistics of compressed natural videos. The model has two stages: 1) distortion measurement and 2) nonlinear mapping. In the first stage, an unsigned ac band, three frequency bands, and two orientation bands are generated from the DCT coefficients of each decoded frame in a video sequence. Six efficient frame-level features are then extracted to quantify the distortion of natural scenes. In the second stage, each frame-level feature of all frames is transformed to a corresponding video-level feature via a temporal pooling, then a trained multilayer neural network takes all video-level features as inputs and outputs, a score as the predicted quality of the video sequence. The proposed method was tested on videos with various compression types, content, and resolution in four databases. We compared our model with a linear model, a support-vector-regression-based model, a state-of-the-art training-based model, and a four popular full-reference metrics. Detailed experimental results demonstrate that the results of the proposed method are highly correlated with the subjective assessments.

An adaptive complexity reduction scheme with fast prediction unit decision for HEVC intra encoding

Abstract: The next-generation High Efficiency Video Coding (HEVC) standard aims at providing double compression compared to the state-of-the-art H.264/AVC standard. However, this improved compression efficiency accompanies high computational complexity, which is primarily due to the recursive nature of the Coding Tree Unit structure and complex Rate-Distortion (RD) Optimization of Prediction Units (PU). In this paper, we propose a content-driven adaptive complexity reduction scheme that employs an a priori PU size selection algorithm. We adaptively combine smaller PUs into larger PUs depending upon the video frame contents under consideration. Our scheme eliminates the need for recursive or iterative RD cost comparisons to select the best PU size for an HEVC intra encoder. Experimental results demonstrate that the proposed scheme provides significant time savings (on average 43.74 %) for HEVC intra encoding, while incurring an insignificant video quality loss (on average -0.048 dB BD-PSNR).

Reliable transmission of video over ad-hoc networks using automatic repeat request and multipath transport

Abstract: The increase in the bandwidth of the wireless channels and the computing power of the mobile devices makes it possible to offer video service for wireless networks in the near future. In an ad-hoc network, strong error protection is required because of the lack of a fixed infrastructure. On the other hand, the mesh structure of an ad-hoc network implies that there may be multiple paths existing between a source and destination, which can be used to enhance video transmissions. We propose a simple but robust scheme for reliable transmission of video in bandwidth limited ad-hoc networks. In our scheme, a video stream is layer coded. The base layer (BL) packets and the enhancement layer (EL) packets are transmitted separately on two disjoint paths using multipath transport (MPT). BL packets are protected by automatic repeat request (ARQ), and a lost BL packet is retransmitted through the path where EL packets are transmitted. An EL packet has lower priority than a retransmitted BL packet and may be dropped at the sender when congestion occurs. Simulation results show that this scheme can guarantee a graceful video quality in adverse channel conditions. It is effective for video transmission over the high loss environment found in ad-hoc networks.

IPTV service assurance

Abstract: This article discusses service assurance aspects specific to IPTV services and video quality. Classic network monitoring generally ensures that each network element, network segment, and subnetwork is functioning reliably, and may also encompass routing and reachability across different network domains. IPTV service assurance can encompass much more, including subscriber management and authorization, capacity management, perceived video picture quality, and error correction and concealment; accomplished through integrated test and monitoring for rapid resolution of customer complaints. This is all needed to ensure that the customer has an overall video quality of experience (QoE) at least as enjoyable as current TV delivery methods

Information Hiding Based on Intra Prediction Modes for H.264/AVC

Abstract: This paper presents a novel information hiding algorithm for H264/AVC, taking advantage of the specific features of this advanced video compression standard The algorithm hides 1 bit in each qualified intra 4x4 luma block by modifying intra 4x4 prediction modes (I4-modes) based on the mapping between I4-modes and hiding bits Information hiding rate is controlled by a parameter, embedding strength, which is also embedded into bitstream Hidden information can be retrieved by decoding the intra prediction modes from bitstream, requiring neither original media nor complete video decoding Experimental results show that the proposed algorithm almost has no impact on video quality and video stream features A comparatively high data hiding rate is obtained with a little increase on bit rate