CLAIMS
1. A method for coding an image (ICj) split up into blocks, said image containing
first and second distinct zones (Z1, Z2),
said coding method being characterized in that it implements the following, for at least one current block (Bu) of the image:
- determine (C4) to which of the first and second zones the current block belongs,
- if the current block belongs to the first zone (Z1), code (C5a)) the current block with the aid of a first coding scheme (MC1),
- if the current block belongs to the second zone (Z2), code (C5b)) the current block with the aid of a second coding scheme (MC2) which comprises the following:

- on the basis of the position of the current block in the second zone, identify (C51b)) a previously coded, and then decoded, block (Bref) situated in the first zone of the image,
- copy the value of at least one coding parameter (PRCi) associated with the identified block.
2. The coding method as claimed in claim 1, in which the second coding
scheme is applied to all the blocks of the second zone of the current image.
3. The coding method as claimed in claim 1, implementing the following:
- code (C100b)) said at least one current block of the second zone of the image with the aid of the first coding scheme (MC1),
- select (C200b)) the first coding scheme or the second coding scheme in accordance with a predetermined coding performance criterion,
- code (C300b)) an item of information (ES_MCoPt) representative of said selection.
4. The coding method as claimed in any one of claims 1 to 3, in which the first
and second zones of the image have the same shape, the first zone being

situated above the second zone and separated from the latter by a horizontal boundary extending along the middle of the image.
5. A device (CO) for coding at least one image (ICj) split up into blocks, said
image containing first and second distinct zones, characterized in that it
comprises a processing circuit (CT_C) which is designed to implement the
following, for at least one current block of the image:
- determine to which of the first and second zones the current block belongs,
- if the current block belongs to the first zone (Z1), code the current block with the aid of a first coding scheme (MC1),
- if the current block belongs to the second zone (Z2), code the current block with the aid of a second coding scheme (MC2) which comprises the following:

- on the basis of the position of the current block in the second zone, identify a previously coded, and then decoded, block (Bref) situated in the first zone of the image,
- copy the value of at least one coding parameter (PRCi) associated with the identified block.
6. 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 4, when
said program is executed on a computer.
7. 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 4, when
said program is executed by a computer.
8. A method for decoding a data signal (F) representative of an image (IQ) split
up into blocks which has been coded, said at least one image containing first
and second distinct zones (Z1, 72),

said decoding method being characterized in that it implements the following, for at least one current block (Bu) to be decoded of the image:
- determine (D5) to which of the first and second zones the current block belongs,
- if the current block belongs to the first zone (Z1), decode (D6a)) the current block with the aid of a first decoding scheme (MD1),
- if the current block belongs to the second zone (Z2), decode (D6b)) the current block with the aid of a second decoding scheme which comprises the following:

- on the basis of the position of the current block in the second zone, identify (D61b)) a previously decoded block, situated in the first zone of the image,
- assign (D64b)) to the current block at least one decoding parameter (PRDi) associated with said identified block.
9. The decoding method as claimed in claim 8, in which the second decoding
scheme is applied to all the blocks of the second zone of the current image.
10. The decoding method as claimed in claim 8, in which the second decoding scheme is applied to the current block of the second zone if, for said current block, an item of information in respect of selection of said second decoding scheme is read (D100b)) in the data signal (F1), the first decoding scheme being applied to the current block of the second zone if, for said current block, an item of information in respect of selection of said first decoding scheme is read in the data signal.
11. The decoding method as claimed in any one of claims 8 to 10, in which the first and second zones of the image have the same shape, the first zone being situated above the second zone and separated from the latter by a horizontal boundary extending along the middle of the image.
12. A device 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 first

and second distinct zones, characterized in that it comprises a processing circuit (CT_D) which is designed to implement the following, for at least one current block to be decoded of the image:
- determine to which of the first and second zones the current block belongs,
- if the current block belongs to the first zone (Z1), decode the current block with the aid of a first decoding scheme (MD1),
- if the current block belongs to the second zone (Z2), decode the current block with the aid of a second decoding scheme which comprises the following:
- on the basis of the position of the current block in the
second zone, identify a previously decoded block, situated in the first zone of
the image,
- assign to the current block at least one decoding
parameter (PRDi) associated with said identified block.
13. A computer program comprising program code instructions for the execution
of the steps of the decoding method as claimed in any one of claims 8 to 11,
when said program is executed on a computer.
14. 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 8 to 11, when
said program is executed by a computer.