Cloud gaming enables playing high-end games, originally designed for PC or game console setups, on low-end devices such as netbooks and smartphones, by offloading graphics rendering to GPU-powered cloud servers. However, transmitting the high-resolution video requires a large amount of network bandwidth, even though it is compressed stream. Foveated encoding (FVE) reduces bandwidth requirement taking advantage non-uniform acuity human visual system knowing where user looking. Based...

Live multimedia streaming from mobile devices is rapidly gaining popularity but little known about the QoE they provide. In this paper, we examine Periscope service. We first crawl service in order to understand its usage patterns. Then, study protocols used, typical quality of experience indicators, such as playback smoothness and latency, video quality, energy consumption Android application.

We present a new cross-layer ARQ algorithm for video streaming over 802.11 wireless networks. The combines application-level information about the perceptual and temporal importance of each packet into single priority value, which drives selection at retransmission opportunity. Hence, only most perceptually important packets are retransmitted, delivering higher quality less bandwidth usage compared to standard MAC-layer scheme. H.264 based on proposed technique has been simulated using ns in...

This paper evaluates the performance of video streaming in inter-vehicular environments using 802.11 ad hoc network protocol. We performed transmission experiments while driving two cars equipped with 802.11b standard devices urban and highway scenarios. Different sequences, bitrates packctization policies have been tested. The show that each scenario presents peculiar characteristics terms average link availability SNR, which can be exploited to develop more efficient applications. In this...

The H.264/SVC video codec extends the H.264/AVC standard with scalability features. In this paper we introduce a traffic prioritization algorithm suitable for transmission of both and over 802.11e ad hoc wireless networks. proposed exploits capabilities offered by to provide better protection most perceptually important parts while achieving efficient network resource usage. We evaluate simulating transmissions in an scenario. Results show that particularly benefits from algorithm, which...

Several approaches have been proposed to estimate quality in subjective experiments while highlighting peculiar subject behaviors. However, there is some room for improvement existing approaches, both terms of robustness noise and the ability accurately indicate several behaviors experiments. This work advances state-of-the-art three main directions: i) A new approach from noisy ratings shown be more robust than are four approaches; ii) a novel scoring model that makes it possible highlight...

The popularity of DASH streaming is rapidly increasing and a number commercial services are adopting this new standard. While the benefits building on top HTTP protocol clear, further work still necessary to evaluate enhance system performance from perspective end user. Here we present novel framework rate-adaptation algorithms for using network measurements collected more than thousand Internet clients. Data, which have been made publicly available, by module built Neubot, an open source...

Sharing live multimedia content is becoming increasingly popular among mobile users. In this article, we study the problem of optimizing video quality in such a scenario using scalable coding (SVC) and chunked content. We consider only standard stateless HTTP servers that do not need to perform additional processing Our key contribution provide close optimal algorithms for scheduling chunk upload multiple clients having different viewing delays. Given set clients, decide which chunks order...

This paper presents an analysis-by-synthesis technique to evaluate the perceptual importance of multimedia packets for rate-distortion optimized streaming. The proposed technique, instead relying on a priori information, computes distortion that would be caused by loss each single packet, including effects error propagation and receiver-side concealment. A streaming algorithm is presented compare performance obtained using content-adaptive values versus knowledge statistical elements...

Good user experience with interactive cloud-based multimedia applications, such as cloud gaming and VR, requires low end-to-end latency large amounts of downstream network bandwidth at the same time. In this paper, we present a foveated video streaming system for gaming. The adapts stream quality by adjusting encoding parameters on fly to match player's gaze position. We conduct measurements prototype that developed in conjunction eye tracker hardware. Evaluation results suggest can reduce...

The current development of video quality assessment algorithms suffers from the lack available sequences for training, verification and validation to determine enhance algorithm's application scope. Joint Effort Group Video Quality Experts (VQEG-JEG) is currently driving efforts towards creation large scale, reproducible, easy use databases. These databases will contain bitstreams recent encoders (H.264, H.265), packet loss impairment patterns impaired bitstreams, pre-parsed bitstream...

We present a new algorithm for the dynamic identification of perceptually important regions in pictures video sequence. For each macroblock, distortion that its loss would cause at decoder is computed. High-distortion macroblocks are then grouped together into slices to be protected with forward error correction or sent as "premium" packets. developed approach case sequences encoded ISO MPEG-2 coding standard. applied classify packets within 1-bit differentiated services architecture: were...

This work presents an application-level perceptual ARQ algorithm for video streaming over 802.11e wireless networks. A simple and effective formula is proposed to combine the temporal importance of each packet into a single priority value, which then used drive packet-selection process at retransmission opportunity. Compared standard 802.11 MAC-layer scheme, technique delivers higher quality because it can retransmit only most perceptually important packets reducing bandwidth waste. Video...

Broadcasting live video directly from mobile devices is rapidly gaining popularity with applications like Periscope and Facebook Live. The quality of experience (QoE) provided by these services comprises many factors, such as transmitted video, playback stalling, end-to-end latency, impact on battery life, they are not yet well understood. In this article, we examine mainly the service through a comprehensive measurement study compare it in some aspects to We shed light usage analysis...

The media quality assessment research community has traditionally been focusing on developing objective algorithms to predict the result of a typical subjective experiment in terms Mean Opinion Score (MOS) value. However, MOS, being single value, is insufficient model complexity and diversity human opinions encountered an actual experiment. In this work we propose complementary approach for that attempts more closely what happens observers and, at same time, perform qualitative analysis...

This paper presents an algorithm to optimize the tradeoff between rate and expected end-to-end distortion of a video sequence transmitted over packet network. The approach optimizes source coding parameters, slicing, network QoS class selection and/or error control accounts for effects compression, packetization, propagation, concealment at decoder. It builds on, substantially extends applicability of, recursive optimal per-pixel estimate (ROPE) technique estimation. A trellis-based is...

This paper presents a new ARQ algorithm for video streaming over wireless channels. The takes into account the perceptual and temporal importance of each packet to determine scheduling which maximizes perceived quality. A simple flexible function combine with real-lime constraints is best transmit at transmission opportunity proposed. evaluated using analysis-by-synthesis technique. performance proposed has been analyzed by simulating H.264 encoded sequences 144 kbit/s UMTS channel compares...

This work proposes a quality-oriented multimedia delivery framework that tackles the issue of optimizing video broadcasting and interactive applications over packet networks with respect to both resource utilization user perceived quality. Previous showed quality service requirements can be optimally satisfied by pipeline forwarding packets keeping delay controlled high, while enabling highly scalable network devices. These properties are key in today enable valuable (i.e., chargeable for)...

The training and performance analysis of objective video quality assessment algorithms is complex due to the huge variety possible content classes transmission distortions. Several secondary issues such as free parameters in machine learning alignment subjective datasets put an additional burden on developer. In this paper, three subsequent steps are presented address issues. First, coding parameter space a large-scale database used select dedicated subsets for algorithms. This aims at...

Despite several approaches to recover the ground truth subjective quality score from noisy individual ratings in experiments have been explored literature, there is still room for improvement, particular terms of robustness noise. This paper proposes a new approach that combines traditional maximum likelihood estimation framework with newly proposed regularization term, based on information theory concepts, meant underweight surprising given stimulus, looked at as noise manifestation, final...

We present a technique to enhance real-time video transmissions over 802.11-based ad hoc networks. propose limit the coverage of error detection mechanism most sensitive bit class contained in packets. Packets are retransmitted only if errors affect those bits, instead retransmitting all corrupted packets irrespective positions. The expectation was that negative effects less bits should be more than adequately counterbalanced by lower number discarded Moreover, retransmissions reduce network...