In this paper we study the performance requirements for the transport of MPEG video streams over ATM networks. The use of two different schemes is studied to overcome for the loss of information when transferring video sequences through ATM networks. In the first scheme, the prioritization scheme assigns different priorities to the video stream based on the different types of video frames. In the second scheme, the use of dummy cells to replace for lost ATM cells is investigated. For this second scheme, different patterns for the dummy cells to be used are investigated. Statistics of signal to noise ratio (SNR) for cell loss ratio (CLR) in each cases are presented. Statistics gathered from both types of schemes can be applied in several ways for network design and operation.