The present invention relates to a method and a device for choosing a mode of coding from among a plurality of modes of coding for a subset of blocks included in a set of blocks. An energy function over the set of blocks for each of the modes of coding is calculated and calculation elements of the energy function are stored for at least the subset of blocks. A first mode of coding, minimizing the energy function over the set of blocks is chosen. The energy function over the subset of blocks for each of the modes of coding is thereafter calculated by using the calculation elements stored for the subset of blocks and by said subset, of a cost of coding for the modes of coding distinct from the first mode of coding. The choice of a mode of coding minimizing the energy function over the subset is then effected.