Abstract: A process for controlling the output flow rate of a coder of digital data representative of sequences of images, the coding effected by the coder including a quantization stage of quantization parameter Q, the sequences of images being made up of successive groups of images. The process consists of determining, at the moment of the presence of the i group of images at the output of the coder, the quantization parameter Q(i+1) for the coding of the (i+1) group of images so that the flow rate at the output of the coder conforms with a version of a leaky bucket defined by a size M and by a leakage rate .lambda. in terms of the activity of the scene represented by the i group of images.