The arrangement of data in a variable bit rate (VBR) video codec, making it suitable for the transmission over ATM (asynchronous transfer mode) networks, is addressed. Attention is focused on two aspects specifically belonging to the ATM environment: the impairment due to the loss of ATM data cells and the statistical analysis of a real VBR video source. A particular implementation of a hybrid DCT (discrete cosine transform) broadcast video codec, which adheres to the recent specifications proposed by the European Telecommunications Standards Institute, is addressed. In order to optimize the performance with respect to cell losses, a specific solution based on the concept of organizing data into video packets is explored. The statistical characteristics of the available VBR video source are investigated, using a real-time acquisition system.
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