The method of transmission of a datastream representing a sequence of images over a network in which the quantity of information that may be sent per unit of time varies substantially cyclically, said transmission extending over a plurality of cycles, comprises: a step (805 to 807, 809, 810) of determining times for which the quantity of information that may be sent per unit of time over the network is greater, and respectively less, than its average, on the basis of the substantially cyclical past variation in said quantity of information and a step (801 to 805, 812 to 816) of sending over said network, at said times, images corresponding to a greater, and respectively smaller, quantity of information than the average of the images. During the determining step, a period of cyclical variation of the quantity of information that may be sent over the network is determined.