Multimedia Streaming

HTTP Adaptive Streaming (HAS) has become a predominant technique for delivering videos in the Internet. Due to its adaptive behavior according to changing network conditions, it may result in video quality variations that negatively impact the Quality of Experience (QoE) of the user. In this paper, we propose Days of Future Past, an optimizationbased Adaptive Bitrate (ABR) algorithm over HTTP/3. Days of Future Past takes advantage of an optimization model and HTTP/3 features, including (i) stream multiplexing and (ii) request cancellation. We design a Mixed Integer Linear Programming (MILP) model that determines the optimal video qualities of both the next segment to be requested and the segments currently located in the buffer. If better qualities for buffered segments are found, the client will send corresponding HTTP GET requests to retrieve them. Multiple segments (i.e., retransmitted segments) might be downloaded simultaneously to upgrade some buffered but not yet played segments to avoid quality decreases using the stream multiplexing feature of QUIC. HTTP/3's request cancellation will be used in case retransmitted segments will arrive at the client after their playout time. The experimental results shows that our proposed method is able to improve the QoE by up to 33.9%.

Quality of Service (QoS) and Quality of Experience (QoE) are considered key performance indicators of video and audio conference performance of video call streaming service. Since Skype operates and evolves around the scope of achieving best possible quality service across all available operative environments, it is important to investigate and examine how Skype has evolved around this cross platform scope, what kind of encoding improvements have been implemented through years and how efficient are all these changes, objectively and subjectively.

The MPEG-4 standard encodes a video stream in 3 dierent frames, I, P and B, where the P and B frames depend on the I frame. Loosing an I frame is especially bad. In this paper we exploit the Partial Reliabil- ity features of the SCTP transport protocol to selectively retransmit I frames in presence of congestion, obtaining a better

Multicast routing is again gaining popularity with the development of new group services, like real-time multimedia streaming. The aim is to reach big groups of users with the quality level they expect, while using network resources in an efficient way. This is a challenge to be fulfilled as current multicast protocols still have difficulties in dealing with basic issues like asymmetric routing. In this work we describe and evaluate an overlay that allows the use of the source-specific multicast standard in environments with asymmetric ...

The paper mathematically frames the relation between window-based and rate-based congestion control algorithms, when the assumption of variable round-trip time conditions is introduced. Under this hypothesis, the local stability analysis of a specific class of source, window-based controls is first developed; then a new, rate-based control suitable for use by multimedia streams is proposed. The novel strategy is demonstrated to guarantee consistent and intra-fair throughput allocation, good responsiveness and satisfying smoothness, even in a first, easy-to-implement version.

After a year of pandemic, we can say that the cinema landscape has changed completely, from empty theaters, postponed premieres, interrupted shootings, professionals in crisis, etc. However, in addition to the crisis caused, streaming was consolidated and became the main way to watch films during this period. Nonetheless, it raises questions about the vitality and sustainability of the model that we knew until then. In this article, we propose to portray a year of pandemic in three distinct moments: the effects caused by Covid-19 on the cinematographic sector, the strengthened presence of streaming and the consequences for the traditional model of cinema, and a question about the paths that cinema will take trail in the near future.

The recent advent of high speed trains introduces
new mobility patterns in wireless environments. The LTE-A
(Long Term Evolution of 3GPP - Advanced) networks have
largely tackled the Doppler effect problem in the physical layer
and are able to keep wireless service with 100Mpbs throughput
within a cell in speeds up to 350 km/h. Yet the much more
frequent handovers across cells greatly increases the possibility
of service interruptions, and the problem is prominent for
multimedia communications that demand both high-throughput
and continuous connections.
In this paper, we present a novel LTE-based solution to
support high throughput and continuous multimedia services
for high speed train passengers. Our solution is based on a
Cell Array that smartly organizes the cells along a railway,
together with a femto cell service that aggregates traffic demands
within individual train cabins. Given that the movement direction
and speed of a high-speed train are generally known, our Cell
Array effectively predicts the upcoming LTE cells in service, and
enables a seamless handover that will not interrupt multimedia
streams. To accommodate the extreme channel variations, we
further propose a scheduling and resource allocation mechanism
to maximize the service rate based on periodical signal quality
changes. Our simulation under diverse network and railway/train
configurations demonstrates that the proposed solution achieves
much lower handover latency and higher data throughput, as
compared to existing solutions. It also well resists to network and
traffic dynamics, thus enabling uninterrupted quality multimedia
services for passengers in high speed trains.

The aim of this paper is to present the possibilities offered by Internet and current multimedia tools to delivery high quality courses with cost effectiveness and a low complexity infrastructures. It covers topics of interest relative to the streaming multimedia content from different points of view, such as the hardware/software infrastructure required, the steps involved in creating multimedia content, and

HTTP-based Adaptive Streaming (HAS) plays a key role in over-the-top video streaming. It contributes towards reducing the rebuffering duration of video playout by adapting the video quality to the current network conditions. However, it incurs variations of video quality in a streaming session because of the throughput fluctuation , which impacts the user's Quality of Experience (QoE). Besides, many adaptive bitrate (ABR) algorithms choose the lowest-quality segments at the beginning of the streaming session to ramp up the playout buffer as soon as possible. Although this strategy decreases the startup time, the users can be annoyed as they have to watch a low-quality video initially. In this paper, we propose an efficient retransmission technique, namely H2BR, to replace low-quality segments being stored in the playout buffer with higher-quality versions by using features of HTTP/2 including (i) stream priority, (ii) server push, and (iii) stream termination. The experimental results show that H2BR helps users avoid watching low video quality during video playback and improves the user's QoE. H2BR can decrease by up to more than 70% the time when the users suffer the lowest-quality video as well as benefits the QoE by up to 13%. CCS CONCEPTS • Information systems → Multimedia streaming; • Networks → Application layer protocols.

This paper proposes a remote thin client system for real time multimedia streaming over VNC. A remote frame can be split as two parts, i.e. high motion part and low motion part, and transmitted through the Internet from servers to clients according to the proposed hybrid RTP protocol. A Dynamic Image Detection Scheme (DIDS) is proposed to automatically detecting the high motion part of a frame with only 1% of extra CPU loading. In addition, an Error Detection Scheme (EDS) and a Dynamic Bit-rate Control Scheme (DBCS) are also proposed to ensure good video streaming quality under bandwidth limited applications. This paper also proposes a linear time BU-level rate control algorithm to ensure the proposed DBCS can be finished in real time. The proposed algorithm reduces the computational complexity from O(n2)to be O(n). By using the proposed thin client system, we can achieve about 22 fps of real-time SIF video streaming with good video quality under 32 KByte/s of bandwidth limitation, which speeds up about 172 times in remote frame display when compared to pure VNC.