This document relates to video transport systems and in particular, though not exclusively, where several compressed or encoded video services are multiplexed into a fixed bit rate transmission stream. There is provided a method of allocating bit-rates for video services in a transport channel. The method comprises receiving user defined weighting parameters for a number of video services (410); then determining an available bit-rate for a transport channel for the video services (420). The method then automatically allocates a proportion of the available bit-rate to each video service according to their respective weighting parameters (430); and multiplexes the video services into the transport channel according to the allocated proportions of the available bit-rate (440).