Streaming audio/video contents over the Internet requires large network bandwidth and timely delivery and playback of the media data. However, large network latency and jitter cause long start-up delay and frequent unwanted pauses in the playback, respectively. An entire audio/video media file cannot be cached due to intellectual property right concerns of the content owners, security reasons, and also due to its large size. This makes a streaming service hard to scale using conventional proxy caches. Media file compression using variable-bit-rate (VBR) encoding is often preferred in order to get constant quality compressed videos. VBR-encoding produces traffic burst, which not only wastes bandwidth but also inserts hiccup in the media playback. The standard frame sequence of a compressed video stream is only suitable for normal playback. lts inter-frame dependency makes it difficult to play it in interactive playback modes, such as fast forward/backward, jump and play backward. Moreover, different interactive clients generally ask for different playback sequences. Hence, they cannot be served together using a common server stream. Therefore, as the frequency of interaction increases, an ordinary scalable streaming service transforms into a non-scalable service. In this thesis, we present a new proxy based constant-bit-rate (CBR) streaming scheme that allows a server to transmit a VBR-encoded video at a fixed rate, close to its mean encoding bit-rate, and deals with the network latency and jitter issues efficiently without caching an entire media file at the proxy. We use a prefix buffer at the proxy to cache the prefixes of popular videos in order to minimize the start-up delay and to enable near mean bit rate streaming. We present a new proxy based scalable streaming scheme that uses our CBR streaming scheme. We use the smoothing buffer at the proxy not only to eliminate jitter and traffic burst effects but also to enable many clients to share the same server stream. We also present a new interactive and scalable streaming scheme, which divides a video stream into several logical segments and provides segment-by-segment interactive playback options to the clients. We use hybrid temporal-data-partition scalable encoding to create a suitable playback sequence for the interactive playback modes. Experimental result shows that our streaming scheme remains fully scalable even when all the clients are highly interactive. As further improvements, we present a new on demand and user driven segmentation and proxy buffer provisioning (prefix caching) mechanism for our interactive and scalable streaming scheme in order to avoid buffer over provisioning at the proxy as well as to avoid the use of complex video segmentation algorithms. We also present a new collaborative-proxy-peering system in order to get better resource utilization and performance from a set of proxies that are used to stream a video. Mathematical expressions to compute the precise sizes of the prefix and the smoothing buffers as well as the precise amounts of bandwidth requirements have been developed. All our streaming schemes have been analyzed and the results of Java simulation programs have shown their effectiveness.

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Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The way in which people consume video is changing with the adoption of new technologies such as tablet computers and smart televisions. These new technologies, along with the Internet, are moving video distribution away from satellite and terrestrial broadcast to distribution over the Internet. Services online now offer the same content that originally was only available on satellite broadcast television. However, these services are only viable in countries with high speed, inexpensive Internet bandwidth. The need therefore exists for alternative services to deliver content in countries where bandwidth is still expensive and slow. These include many of the developing nations of Africa. In this thesis we design and develop a video distribution platform that relies on peer-to-peer networking to deliver high quality video content. We use an existing video streaming peer-to-peer protocol as the primary distribution mechanism, but allow users to share video over other protocols and services. These can include BitTorrent, DC++ and users sharing hard drives with one another. In order to protect the video content, we design and implement a security scheme that prevents users from pirating video content, while allowing easy distribution of video data. The core of the security scheme requires a low bandwidth Internet connection to a server that streams keys to unlock the video content. The project also includes the development of a custom video player application to integrate with the security scheme. The platform is not limited to, but is aimed at high speed local area networks where bandwidth is free. In order for the platform to support feasible business models, we provision additional services, such as video cataloging and search, video usage monitoring and platform administration. The thesis includes a literature study on techniques and solutions to secure video entertainment, specifically in a peer-to-peer environment. / AFRIKAANSE OPSOMMING: Die wyse waarvolgens mense video verbruik is aan die verander met die ingebruikneming van nuwe tegnologie soos tabletrekenaars en slim televisiestelle. Hierdie nuwe tegnologie tesame met die Internet maak dat die verspreiding van video al hoe minder plaasvind deur middel van satellietuitsendings en al hoe meer versprei word deur die Internet. Aanlyn-Internetdienste bied deesdae dieselfde inhoud aan as wat voorheen slegs deur beeldsending versprei is. Hierdie dienste is egter slegs lewensvatbaar in lande met hoëspoed- en goedkoop Internetbandwydte. Daar is dus ’n behoefte aan alternatiewe tot hierdie dienste in lande waar bandwydte steeds duur en stadig is. Baie lande in Afrika kan in hierdie kategorie ingesluit word. In hierdie tesis word ’n videoverspreidingsplatform ontwerp en ontwikkel, wat van portuurnetwerke gebruik maak om hoëkwaliteit-beeldmateriaal te versprei. Die stelsel gebruik ’n bestaande portuurnetwerk-datavloeiprotokol as die premêre verspreidingsmeganisme, maar laat gebruikers ook toe om videoinhoud direk met ander gebruikers en dienste te deel. BitTorrent, DC++ en gebruikers wat hardeskywe met mekaar deel word hierby ingesluit. Ten einde die videoinhoud te beskerm ontwerp en implimenteer ons ’n sekuriteitstelsel wat verhoed dat gebruikers die videoinhoud onregmatig kan toe-eien, maar wat terselfdertyd die verspreiding van die data vergemaklik. Hierdie sluit die ontwikkeling van ’n pasgemaakte videospeler in. Die kern van die sekuriteitstelsel benodig ’n lae-bandwydte-Internetverbinding na ’n bediener wat sleutels uitsaai om die videoinhoud te ontsluit. Alhoewel nie daartoe beperk nie, is die platform gemik op hoëspoed-plaaslikegebiedsnetwerke met gratis bandwydte. Om die platvorm aan ’n haalbare sakemodel te laat voldoen het ons vir addisionele dienste soos videokatalogisering met soekfunksies, videoverbruikersmonitering en platvormadministrasie voorsiening gemaak. Die tesis sluit ’n literatuurstudie oor tegnieke en oplossings vir die beskerming van video data, spesifiek in die portuurnetwerke omgeving, in.