CLAIMS
1. A method for coding an image (ICj) split up into blocks, said image containing
two distinct zones (Z1, 72),
said coding method being characterized in that it implements the following:
- solely in the case where the current block (Bu) belongs to one (Z1) of
said zones of the image:
• code (C6a)-C8a)) the current block with the aid of a prediction, the current block being predicted by using a previously coded and then decoded block situated in the other zone of the image, the blocks of said other zone having been previously coded and then decoded,
• code (C100a)) an item of information (ibc_flag) which indicates the application of the prediction used,
- for any decoded block which belongs to the other (72) of said zones of
the image, store (C101b)) the decoded-block data.
2. The coding method as claimed in claim 1, comprising the coding of at least one item of location information in respect of the previously coded and then decoded block.
3. The coding method as claimed in claim 1 or claim 2, implementing the coding (C3) of an item of identification information (fp_type) in respect of each of the two zones of the image.
4. A device (CO) for coding an image (IQ) split up into blocks, said image containing two distinct zones (Z1, Z2), comprising a processing circuit (CT_C) which is designed to:
- solely in the case where the current block (Bu) belongs to one (Z1) of
said zones of the image:
• code the current block with the aid of a prediction, the current
block being predicted by using a previously coded and then

decoded block situated in the other zone of the image, the blocks of said other zone having been previously coded and then decoded,
• code an item of information which indicates the application of
the prediction used,
- for any decoded block which belongs to the other (Z2) of said zones of
the image, store the decoded-block data.
5. A computer program comprising program code instructions for the execution
of the steps of the coding method as claimed in any one of claims 1 to 3, when
said program is executed on a computer.
6. A recording medium readable by a computer on which is recorded a
computer program comprising program code instructions for the execution of
the steps of the coding method as claimed in any one of claims 1 to 3 when said
program is executed by a computer.
7. A method for decoding a data signal (F) representative of an image (ICj) split
up into blocks which has been coded, said at least one image containing two
distinct zones
said decoding method being characterized in that it implements the following: - solely in the case where the current block (Bu) belongs to one (Z1) of said zones of the image:
• read (D7a) in the data signal an item of information which indicates the decoding of the current block with the aid of a prediction, the current block being intended to be predicted by using a previously decoded block, situated in the other zone (Z2) of the image, the blocks of said other zone having been previously decoded,
• decode (D8a)-D10a)) the current block by using said prediction,
- for any decoded block which belongs to the other (Z2) of said zones of
the image, store (D100b)) the decoded-block data.

8. The decoding method as claimed in claim 7, comprising the reading, in the data signal, of at least one item of location information in respect of the previously coded and then decoded block.
9. The decoding method as claimed in claim 7 or claim 8, in which each of the zones of the image is identified by reading a corresponding item of identification information (fp_type) read in the data signal.
10. A device for decoding a data signal (F) representative of an image (ICj) split
up into blocks which has been coded, said image containing two distinct zones
(Z1, Z2), comprising a processing circuit (CT_D) which is designed to:
- solely in the case where the current block (Bu) belongs to one (Z1) of
said zones of the image:
• read in the data signal an item of information which indicates the decoding of the current block with the aid of a prediction, the current block being intended to be predicted by using a previously decoded block, situated in the other zone (Z2) of the image, the blocks of said other zone having been previously decoded,
• decode the current block by using said prediction,
- for any decoded block which belongs to the other (Z2) of said zones of
the image, store (D100b)) the decoded-block data.
11. A computer program comprising program code instructions for the execution
of the steps of the decoding method as claimed in any one of claims 7 to 9,
when said program is executed on a computer.
12. A recording medium readable by a computer on which is recorded a
computer program comprising program code instructions for the execution of
the steps of the decoding method as claimed in any one of claims 7 to 9, when
said program is executed by a computer.