Towards Smooth and High-Quality Bitrate Adaptation for HTTP Adaptive Streaming

Although HTTP adaptive streaming has been well documented for the cost-effective delivery of video streaming, it is still a great challenge to play back video smoothly with high quality under the fluctuating network conditions. In this paper, we proposed a novel bitrate adaptation algorithm for HTTP adaptive streaming. Our algorithm employed two approaches for throughput estimation and bitrate selection, which was evaluated on our testbed (a fully functional HTTP Live Streaming system) over a network, emulated using DummyNet. First, the throughput estimation method, based on the prediction of the difference between the estimated and instantaneous throughputs, was observed to respond smoothly to short-term fluctuations and rapidly to large fluctuations. Second, the bitrate selection algorithm, based on piecewise functions to define the variation range of the current bitrate, was found to result in smoother changes in quality with a higher average quality. The results of our experiments demonstrated the prospects of our bitrate adaptation algorithm for HTTP adaptive streaming

Adaptive Streaming in P2P Live Video Systems: A Distributed Rate Control Approach

Dynamic Adaptive Streaming over HTTP (DASH) is a recently proposed standard that offers different versions of the same media content to adapt the delivery process over the Internet to dynamic bandwidth fluctuations and different user device capabilities. The peer-to-peer (P2P) paradigm for video streaming allows to leverage the cooperation among peers, guaranteeing to serve every video request with increased scalability and reduced cost. We propose to combine these two approaches in a P2P-DASH architecture, exploiting the potentiality of both. The new platform is made of several swarms, and a different DASH representation is streamed within each of them; unlike client-server DASH architectures, where each client autonomously selects which version to download according to current network conditions and to its device resources, we put forth a new rate control strategy implemented at peer site to maintain a good viewing quality to the local user and to simultaneously guarantee the successful operation of the P2P swarms. The effectiveness of the solution is demonstrated through simulation and it indicates that the P2P-DASH platform is able to warrant its users a very good performance, much more satisfying than in a conventional P2P environment where DASH is not employed. Through a comparison with a reference DASH system modeled via the Integer Linear Programming (ILP) approach, the new system is shown to outperform such reference architecture. To further validate the proposal, both in terms of robustness and scalability, system behavior is investigated in the critical condition of a flash crowd, showing that the strong upsurge of new users can be successfully revealed and gradually accommodated.Comment: 12 pages, 17 figures, this work has been submitted to the IEEE journal on selected Area in Communication

Analysis and implementation of QoE aware rate adaptation algorithms used in dynamic adaptive streaming

U ovom diplomskom radu opisane su teorijske osnove za razumijevanje adaptivnog strujanja video zapisa korištenjem MPEG-DASH standarda. Opisan je postupak standardizacije MPEG-DASH-a, princip rada i interakcija između klijenta i poslužitelja. Detaljno je objašnjena uloga i struktura MPD datoteke s opisima pojedinog elementa unutar MPD-a. Unutar klijentskog programa uz prethodno implementirani LIU adaptacijski algoritam, implementirani su QDASH, BBA i QAAD adaptacijski algoritmi koji u obzir uzimaju kvalitetu korisničkog iskustva. Prikazani su dijagram toka, pseudo kod i način rada pojedinog algoritma. U svrhu usporedbe i provjere uspješnosti implementacije algoritama provedena su testiranja na opisanim testnim scenarijima te su analizirani rezultati testiranja prikazani linijskim grafovima.In this master thesis theoretical basis are given for understanding adaptive video streaming using the MPEG-DASH standard. MPEG-DASH standardization process, how it works and the interaction between client and server are described. Detailed description of the role and structure of the MPD file is given with descriptions of each element within the MPD. Within the client program with the previously implemented LIU adaptation algorithm, QDASH, BBA and QAAD adaptive algorithms were implemented with a goal of improving perceived quality of experience for users. The flow chart and pseudo code are shown and how a particular algorithm works is described. For the purposes of comparison and success verification of the algorithm implementations, testing was carried out on the described test cases and the test results were analyzed using line graphs