Video streaming is one of the most popular applications on Internet-connected devices. In particular, the increasing deployment of LTE/4G technologies and the advancements in display quality and computing power of modern smartphones and tablets have led to a significant growth in video streaming traffic in mobile networks. In these networks, communication and computational resources are not as abundant as that of wired networks or IPTV systems. Therefore, numerous challenges need to be addressed to provide a low cost, high quality video streaming service. Most importantly, adequate computational and networking resources must be available and the streaming service must be adaptive to heterogeneous end user devices and varying network conditions. Towards high-quality and resource-efficient video streaming in mobile networks, in this thesis we propose innovative techniques to address the computational resource efficiency in cloud and on the end user devices. Furthermore, we
address the network fluctuation and noise using a carefully-designed forward error correction technique that also considers the energy limitations of end user devices such as smartphones. Finally, we propose significant improvements over the state-of-the-art techniques to promote collaborative video streaming in smartphones.