1. A method for encoding digital data, comprising: a selection step for selecting between a first encoding mode and a second encoding mode to encode the digital data into an encoded bitstream, the first mode using a first type of entropy encoder other than a Run-Length encoder and the second mode using the first type of entropy encoder combined with the Run-Length encoder; and an adaptation step for adapting the encoders of the first mode and the second mode based on the encoded bitstream using a backward-adaptive technique.