Description of image composition with HEVC still image file format

1. A method of encapsulating an encoded bitstream representing one or more images, the method comprising:

providing description of images and/or sub-image pictures identifying portions of the bitstream representing the images and/or sub-images of the one or more images;

providing composed picture description of at least one composed picture formed by one or more images and/or sub-image pictures; and

outputting the bitstream together with the composed picture description as an encapsulated data file.

2. A method according to claim 1 , wherein the composed picture description is listed in a metadata box.

3. A method according to claim 1 , wherein the composed picture description is signaled by a composed picture item.

4. A method according to claim 1 ,

wherein the composed picture description is signaled by a composed picture item among a plurality of composed picture items, wherein one composed picture item of the plurality of composed picture items corresponds to one type of composition.

5. A method according to claim 1 , further comprising providing reference information linking the composed picture description to the one or more images and/or sub-image pictures forming the at least one composed picture,

wherein outputting includes outputting, in the encapsulated data file, the bitstream together with the reference information.

6. A method according to claim 5 , wherein the reference information includes a reference item.

7. A method according to claim 5 , wherein the reference information comprises information which indicates if images and/or sub-image pictures forming part of the at least one composed picture are spatial parts or based on images.

8. A method according to claim 1 , wherein at least two images and/or sub-image pictures, forming part of the at least one composed picture, identify portions of the bitstream representing two different images and/or sub-images of at least two different images.

9. A method according to claim 8 , further comprising comparing configurations of decoding methods used for decoding the at least two different images and/or sub-image pictures, and,

if the configurations are similar, then

providing only one configuration item identifying the configuration of a decoding method, linked to the at least one composed picture, and

further outputting the bitstream together with the only one configuration item in the encapsulated data file.

10. A method according to claim 1 , wherein the at least one composed picture formed by one or more images and/or sub-image pictures is defined, by default, as an image to display.

11. A method of processing an encapsulated data file, wherein the encapsulated data file includes an encoded bitstream representing one or more images, and information that includes a composed picture description of at least one composed picture, wherein a composed picture is formed by images and/or sub-image pictures that identify portions of the bitstream representing images and/or sub-images of images, the method comprising:

determining the images and/or sub-image pictures forming the composed picture; and

displaying the composed picture.

12. The method of claim 11 , wherein determining includes:

parsing description metadata included in the information in the encapsulated data file, and,

if available, (i) obtaining a composed picture item from the description metadata and parameters related to the composed picture, (ii) obtaining and decoding the images and/or sub-image pictures forming the composed picture, and (iii) composing the images and/or sub-image pictures for providing the composed picture,

else, decoding the encoded bitstream.

13. A method according to claim 11 , wherein the composed picture description is listed in a metadata box.

14. A method according to claim 11 , wherein the composed picture description is signaled by a composed picture item.

15. A method according to claim 11 , wherein the composed picture description is signaled by a composed picture item among a plurality of composed picture items, wherein one composed picture item of the plurality of composed picture items corresponds to one type of composition.

16. A method according to claim 11 , wherein the encapsulated data file further includes reference information linking the composed picture description to the images and/or sub-image pictures forming the composed picture, the method further comprising outputting, in the encapsulated data file, the bitstream together with the reference information.

17. A method according to claim 16 , wherein the reference information includes a reference item.

18. A method according to claim 17 , wherein the reference information comprises information which indicates if images and/or sub-image pictures forming part of the composed picture are spatial parts or based on images.

19. A method according to claim 11 ,

wherein the encapsulated data file further includes images and/or sub-image description information comprising display parameters relating to one or more image and/or sub-image pictures, and

wherein the reference information links a composed picture item to the images and/or sub-image description information.

20. A method according to claim 11 , wherein at least two images and/or sub-image pictures, forming part of the composed picture, identify portions of the bitstream representing two different images and/or sub-images of at least two different images.

21. A method according to claim 20 , wherein the encapsulated data file further includes only one configuration item identifying the configuration of a decoding method for the composed picture.