The focus of research into 5G networks to date has been largely on the required advances in network architectures, technologies and infrastructures. Less effort has been put on the applications and services that will make use of and exploit the flexibility of 5G networks built upon the concept of Software Defined Networking (SDN) and Network Function Virtualization (NFV). Media-based applications are amongst the most demanding services, requiring large bandwidths for high audio-visual quality, low-latency for interactivity and sufficient infrastructure resources to deliver the computational power for running the media applications in the networked cloud. This paper presents a novel Service Virtualization Platform (SVP), called 5G-MEDIA SVP, which leverages the principles of NFV and SDN to facilitate the development, deployment and operation of media services on 5G networks. The platform offers an advanced cognitive management environment for the provisioning of network services (NSs) and media-related applications, which directly link their lifecycle management with user experience as well as optimization of infrastructure resource utilization. Another innovation of 5G-MEDIA SVP is the integration of serverless computing with media intensive applications in 5G networks, increasing cost effectiveness of operation and simplifying development and deployment time. The proposed SVP is being validated against three media use cases: immersive Virtual Reality 3D gaming application, remote production of broadcast content incorporating user generated contents, and dynamically adaptive Content Distribution Networks (CDNs) for the intelligent distribution of Ultra-High Definition (UHD) content. The preliminary results of the 5G-MEDIA SVP platform evaluation are compared against current practice and show that the proposed platform provides enhanced functionality for the operators and infrastructure owners, while ensuring better NS performance to service providers and end users.