A dynamic channel allocation unit for specifying a bit rate for each video coder in a set of parallel video coders comprising an overall video coder is disclosed. The dynamic channel allocation unit is supplied from each individual video coder with an average from quantization step size for the previous frame and the average number of bits produced per pel. For the current image frame the dynamic channel allocation unit computes a set of channel sharing factors, i.e., the percentage of the total channel bandwidth to be allocated to a particular video coder. One channel sharing factor is computed for each individual video coder. Individual members of the set of channel sharing factors may be further refined to reflect the prior history of the channel sharing factor for their corresponding coder. Additionally, the set of estimates may be normalized to reflect the actual number of bits that can actually be produced by each individual video coder.