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Coding Optimisation by Unsteadiness, Grain and Artefact Removal

Objective

The Strategic aim of COUGAR is the development of European VLSI chip-sets to implement the MPEG-2 video standard. Toward this goal, the project addresses four areas:

- Development of a flexible and versatile software model of the video codec.
- Optimisation of the use of the MPEG 'tool-kit' for the broadcast environment.
- Parallel implementation of the prototype coder and decoder in hardware.
- Simulation of the developed codec model in VHDL for direct VLSI implementation.
The development of European very large scale integration (VLSI) chip sets has been investigated in order to implement the moving picture expert group (MPEG) 2 video standard. A flexible and versatile software model of the video codec has been developed. Optimization of the use of the MPEG tool kit for the broadcast environment has been simulated. A method for deriving the MPEG 2 vector field from true interfield interframe motion vectors was implemented. Definition of the architecture of the SNR-capable coder has been completed and construction of the decoder begun. A flexible interface for the coder has been defined enabling the use of external motion estimation equipment. Evaluation of coder and decoder hardware architecture has been achieved with a view to verifiable hardware description language (VHDL) modelling and VLSI implementation. Assessment of effects of typical audio impairments (eg film noise) on the quality of MPEG 2 sound coding has been carried out. The implementation of the prototype codec in real time hardware is essential in order to verify the codec performance on a wide range of source material.
Technical Approach

The project involves three parallel and co-ordinated activities: optimisation of the coding algorithm by computer simulation, construction of a real-time hardware prototype and high level simulation for eventual VLSI implementation.

A central task of the project is to complete the development of a modular, well structured, fully documented, and easy to understand test model simulation. There remains enormous scope for optimisation of coding algorithms, within the confines of the MPEG specification, for a range of applications. COUGAR concentrates on the optimisation of coding performance in the presence of typical signal impairments. The modular approach employed in the codec simulation facilitates a direct transfer to the real time prototype and VLSI implementations.

Finally, the implementation of the prototype codec in real-time hardware is essential in order to verify the codec performance on a wide range of source material. This has been shown to be an essential step in many previous projects where algorithm development was conducted by computer simulation on a limited set of source pictures. MPEG is no exception in this respect.

Key Issues

- Flexibility and user friendliness of algorithm development tools.
- Optimisation of picture quality v. bit-rate for realistic broadcast signal sources.
- Verification of coding effectiveness for a wide range of source material.
- Usability as part of an end-to-end programme chain.

Expected Impact

The project will facilitate the development of MPEG-2 codecs optimised for various applications through its simulation tools. By providing a second generation codec simulation, optimised for use in the broadcast application, the project will establish the minimum bit-rate required for acceptable quality and therefore the number of programmes that can be accommodated in a single transmission channel.

Coordinator

British Broadcasting Corporation (BBC)
Address
Kingswood Warren
KT20 6NP Tadworth
United Kingdom

Participants (6)

Centro Studi e Laboratori Telecomunicazioni SpA (CSELT)
Italy
Address
Via Gugliemo Reis-romoli 274
10148 Torino
ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE
Switzerland
Address

1015 Lausanne
ENST-ARECOM
France
Address
46 Rue Barrault
75634 Paris
Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV (FhG)
Germany
Address
Am Weichselgarten 3
91058 Erlangen
INESC
Portugal
Address
Largo Montpilher, 22, Apartado 4433
4007 Porto Codex
Snell and Wilcox Ltd
United Kingdom
Address
Durford Mill
GU31 5AZ Petersfield