Image decoding method, encoding method, devices, terminal equipment and computer programs therefor

A device for decoding a stream of coded data representing at least one image divided into a plurality of blocks, where the device comprises:

• a computing machine configured or dedicated to:
• for a current block of the image, comprising a predetermined number My of rows and a predetermined number Mh of columns:
• decoding data corresponding to the current block, including
• decoding an index representative of an identifier identifying a transform among a plurality of transforms, each transform of the plurality being expressed as a vertical subtransform of size Mv*Mv and a horizontal subtransform of size Mh*Mh, and applying the identified transform to decoded data corresponding to the current block, by application of the vertical sub-transform and then of the horizontal subtransform;
• wherein applying the identified transform comprises, for the application of at least one subtransform:
• getting coefficients of the at least one subtransform from a core transform, belonging to the plurality of transforms, said core transform comprising a number M′v of rows of non-zero coefficients less than the number My of rows of the current block.