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Several aspects of the coding of video services in an ATM network environment have been studied. Variable Bit Rate (VBR) coding is discussed and the conditions for its effective application are explained. A method for the synchronization of VBR coded video services under the constraints of cell delay jitter is proposed. The role of the input buffer at the decoder side is explained, and the size is calculated for VBR connections. The influence of cell loss on picture quality is discussed and it is explained how cell loss can be concealed using a layered coding model.

As the ATM technique matures several solutions have been proposed for the integration of video codecs in the broadband ISDN. At present, two approaches can be distinguishedThe first aims at the integration of video codecs, that were developedfor synchronous networks, in the ATM network For these codecs, adoptors are developed that provide the necessary circuit emulation over the ATM network, with the required quality. In the paper special attention is paid to synchronization, dejittering and cell loss protection issues.The second scenario is bared on a new generation of video codecs that a n being developed especially for the ATM network These codecs take full advantage of the flexibility offered by the ATM network, and allow cell loss concealment techniques to be used. In the paper Variable Bit Rate video coding and the associated bandwidrh allocation and policing algorithms are discussed. Special features such as user selectable picture quality are shown Cell loss detection and concealment techniques are discussed.