9 research outputs found
Insights from Analysis of Video Streaming Data to Improve Resource Management
Today a large portion of Internet traffic is video. Over The Top (OTT)
service providers offer video streaming services by creating a large
distributed cloud network on top of a physical infrastructure owned by multiple
entities. Our study explores insights from video streaming activity by
analyzing data collected from Korea's largest OTT service provider. Our
analysis of nationwide data shows interesting characteristics of video
streaming such as correlation between user profile information (e.g., age, sex)
and viewing habits, viewing habits of users (when do the users watch? using
which devices?), viewing patterns (early leaving viewer vs. steady viewer),
etc. Video on Demand (VoD) streaming involves costly (and often limited)
compute, storage, and network resources. Findings from our study will be
beneficial for OTTs, Content Delivery Networks (CDNs), Internet Service
Providers (ISPs), and Carrier Network Operators, to improve their resource
allocation and management techniques.Comment: This is a preprint electronic version of the article accepted to IEEE
CloudNet 201
Recurrent 3D Pose Sequence Machines
3D human articulated pose recovery from monocular image sequences is very
challenging due to the diverse appearances, viewpoints, occlusions, and also
the human 3D pose is inherently ambiguous from the monocular imagery. It is
thus critical to exploit rich spatial and temporal long-range dependencies
among body joints for accurate 3D pose sequence prediction. Existing approaches
usually manually design some elaborate prior terms and human body kinematic
constraints for capturing structures, which are often insufficient to exploit
all intrinsic structures and not scalable for all scenarios. In contrast, this
paper presents a Recurrent 3D Pose Sequence Machine(RPSM) to automatically
learn the image-dependent structural constraint and sequence-dependent temporal
context by using a multi-stage sequential refinement. At each stage, our RPSM
is composed of three modules to predict the 3D pose sequences based on the
previously learned 2D pose representations and 3D poses: (i) a 2D pose module
extracting the image-dependent pose representations, (ii) a 3D pose recurrent
module regressing 3D poses and (iii) a feature adaption module serving as a
bridge between module (i) and (ii) to enable the representation transformation
from 2D to 3D domain. These three modules are then assembled into a sequential
prediction framework to refine the predicted poses with multiple recurrent
stages. Extensive evaluations on the Human3.6M dataset and HumanEva-I dataset
show that our RPSM outperforms all state-of-the-art approaches for 3D pose
estimation.Comment: Published in CVPR 201
ANÁLISE DO PARADIGMA BITTORRENT PARA STREAMING DE VÍDEO SOB DEMANDA NA INTERNET ANTE ACESSO SEQUENCIAL PARTICIONADO SINCRONIZADO
Considering the video-on-demand (VoD) streaming serviceand a mostly sequential-data access pattern by users, thisarticle has the two following goals. Firstly, to analyze theBitTorrent paradigm's eciency under this access-patterntype. Secondly, to propose and analyze a new policy for dataselection by users, denoted as Smart Policy, focused on thisaccess-pattern type. For that, simulations are carried outin dierent VoD streaming scenarios, evaluating a varietyof performance metrics. Compared to previous proposalsin the literature, the nal results highlight optimizationsof up to 24,3% and 100% at the download rate and datawaiting time, respectively. Conclusions and directions forfuture work close this article.DOI: 10.36558/rsc.v11i2.722
Architetture e protocolli di ultima generazione per il live streaming efficiente
In questa tesi verranno analizzati i protocolli e le architetture per il live streaming efficiente, da ciò che è in uso oggi fino a ciò che sarà in arrivo nel prossimo futuro. Partendo con l’enunciare le metriche di misurazione per un live streaming di qualità, sia oggettive che soggettive, verrà poi introdotta la strategia adottata diffusamente per il miglioramento attivo delle suddette metriche. Successivamente verranno introdotti i principali protocolli e ne verranno approfondite struttura e funzionamento. In seguito, si affronteranno confronti ricavati da alcuni studi per poi considerare nuovi possibili metodi di miglioramento degli stessi grazie a ricerche recenti nell’ambito. Per finire analizzeremo le architetture di rete che permettono la diffusione del live streaming
Understanding and Efficiently Servicing HTTP Streaming Video Workloads
Live and on-demand video streaming has emerged as the most popular application for the Internet. One reason for this success is the pragmatic decision to use HTTP to deliver video content. However, while all web servers are capable of servicing HTTP streaming video workloads, web servers were not originally designed or optimized for video workloads. Web server research has concentrated on requests for small items that exhibit high locality, while video files are much larger and have a popularity distribution with a long tail of less popular content. Given the large number of servers needed to service millions of streaming video clients, there are large potential benefits from even small improvements in servicing HTTP streaming video workloads.
To investigate how web server implementations can be improved, we require a benchmark to analyze existing web servers and test alternate implementations, but no such HTTP streaming video benchmark exists. One reason for the lack of a benchmark is that video delivery is undergoing rapid evolution, so we devise a flexible methodology and tools for creating benchmarks that can be readily adapted to changes in HTTP video streaming methods. Using our methodology, we characterize YouTube traffic from early 2011 using several published studies and implement a benchmark to replicate this workload. We then demonstrate that three different widely-used web servers (Apache, nginx and the userver) are all poorly suited to servicing streaming video workloads. We modify the userver to use asynchronous serialized aggressive prefetching (ASAP). Aggressive prefetching uses a single large disk access to service multiple small sequential requests, and serialization prevents the kernel from interleaving disk accesses, which together greatly increase throughput. Using the modified userver, we show that characteristics of the workload and server affect the best prefetch size to use and we provide an algorithm that automatically finds a good prefetch size for a variety of workloads and server configurations.
We conduct our own characterization of an HTTP streaming video workload, using server logs obtained from Netflix. We study this workload because, in 2015, Netflix alone accounted for 37% of peak period North American Internet traffic. Netflix clients employ DASH (Dynamic Adaptive Streaming over HTTP) to switch between different bit rates based on changes in network and server conditions. We introduce the notion of chains of sequential requests to represent the spatial locality of workloads and find that even with DASH clients, the majority of bytes are requested sequentially. We characterize rate adaptation by separating sessions into transient, stable and inactive phases, each with distinct patterns of requests. We find that playback sessions are surprisingly stable; in aggregate, 5% of total session duration is spent in transient phases, 79% in stable and 16% in inactive phases. Finally we evaluate prefetch algorithms that exploit knowledge about workload characteristics by simulating the servicing of the Netflix workload. We show that the workload can be serviced with either 13% lower hard drive utilization or 48% less system memory than a prefetch algorithm that makes no use of workload characteristics