Introduction
Some years ago, Philips introduced Natural Motion as the latest in a series of innovations that has made television viewing more pleasant. It does so by creating and displaying new pictures in between two subsequent original pictures, in which moving objects are shown at positions where the brain 'expects' them. Philips Research is working hard to make Natural Motion available in products other than TV. The BSMART project is an example of this.
The BSMART project has been set up to evaluate opportunities for Natural Motion to improve the coding efficiency in traditional video compression schemes. One of the scenarios is a proprietary extension to the MPEG2 standard where the decoder uses Natural Motion to autonomously generate B-frames from adjacent I- and P- anchor frames. Large parts of these ‘N-frames’ can replace the original B-frames without loss of perceived video quality (Fig.1). Since the encoder does not have to send complete B-frames anymore, a significant gain in compression efficiency can be achieved.

Fig. 1 Part of the BSMART algorithm

Project description
The contribution of the Miplaza prototyping group to this project included the development of a software kit to serve as a toolbox for experiments, enabling the evaluation of both compliant and improved, video compression algorithms based on the integration of MPEG-2 and Natural Motion. The software supports a number of platforms including Linux, MS Windows and Trimedia/Viper. It consists of a variety of components including encoders, decoders and libraries. Many of these components have been re-used from other projects, but the core libraries have been developed from scratch. These libraries have been performance optimized to enable real time execution. The real time aspect of the software was an important requirement. Immediate feedback of algorithmic modifications improved the speed of experimentation and lead to new insights.

Realisation
An application was built that provided simultaneous video encoding on Viper II and decoding on a PC using MPEG-2 and Natural Motion. An early version of the demonstrator comprised a real-time encoder running on a PCI Viper II board and a real-time decoder running on a PC at CIF resolution, 25fps progressive format. The encoded video was transported via PCI to the PC environment (Fig.2). Software development for the Viper was based on the Nexperia / DVP Home software development environment. For the PC, a DirectShow filter has been developed that enabled playback of the BSMART encoded stream on a PC.
The BSMART software environment- and demonstrator was developed by two members of MiPlaza, assisted by the project leader of the customer - Philips Research. The activities were executed over a period of approximately two years.

Fig. 2 BSMART demonstrator setup