Communications, computing
and content research


Coding and transcoding video applications over wired and wireless networks

ROAM4G addresses coding and transcoding video applications over wired and wireless networks, and application and network support for congestion management.  Operators seeking to deliver video clips, broadcasters seeking more channels for distributing content, corporate enterprises seeking to deliver content to a mobile sales force and teleconferencing suppliers seeking to enable hand held devices could all benefit from ROAM4G technology.

The Problem

The massive growth in the communications industry has produced new fixed and mobile systems and advanced cellular services, offering different channel characteristics, range, bit rates and mobility. The delivery of video services to wireless devices in a mobile environment is demanding because of the high bit rates and problems associated with channel errors, packet losses and terminal characteristics.

ROAM4G aims to provide new approaches to robust video transport and congestion management based on scalability, feedback error control and multiple description coding, and performance evaluation over real networks and comparisons with existing methods.

The Research

  • Methods for enhanced Quality of Service provision over IP networks.
  • A robust and efficient video codec based on the new H264 standard.
  • Schemes for the transmission of scalable video content over IP networks.
  • Methods for the exploitation of multiple paths in a network using multiple description coding.
  • Novel transcoding schemes as an alternative to scalability for broadcast and in-home (e.g. set top box) applications.

The Achievements

  • The ability to code video from high quality sources and deliver a reliable quality video experience to remote users, with hand held wireless devices using 802.11b/g WLANs.
  • A novel 3-loop MDC scheme which provides robust transport and graceful degradation over multipath networks using H.264. Comparisons with the state of the art show up to 2dB improvement in PSNR for the same redundancy.
  • A robust 3D scalable wavelet video coder for IP networks combining temporal, spatial and SNR scalability.
  • Packetisation strategies, router forwarding priority mapping strategies and error concealment strategies for scalable video delivery.
  • An efficient means of providing interpolation-free sub-pixel motion estimation in H.264.
  • Robust video transmission using error feedback via a return channel.
  • Efficient algorithms for intra- and inter-frame bitrate transcoding within the H.264 standard with up to 80% less complexity than full decode-recode methods.


  • A Wireless LAN Demonstration which takes a signal from a hand held camera, encodes it using H.264 and then transmits it over a wireless network to a decoder in a PC or PDA.
  • MINT - A demonstration which streams a scalable video bitstream from a server, through a wide area network using novel routing / access point technology, then over a wireless network to a receiving client for video rendering.



Participating Partners

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3C Research Ltd, 2009