Method and apparatus for encapsulating derived tracks
The present invention concerns method of generating a file of image data comprising samples, wherein the method comprises: generating a derived track comprising a derived track configuration data structure and derived samples, the derived track comprising a sequence of derivation operations to be applied on input data, each derivation operation comprising a list of references to input tracks and/or input items; wherein the derived track comprises an information indicating that one input track of a derivation operation is the output of the previous derivation operation in the sequence; and, generating the file comprising the derived track, and the input tracks and/or input items.
1. A method of generating a data file, wherein the method comprises:
obtaining a derived track comprising at least one derived sample, each derived sample comprising a sequence of derivation operations to be performed on a list of at least one input;
wherein the derived track comprises an entry value having its most significant bit set to 1 for indicating that an input of a derivation operation is the output of one among the previous derivation operations in the sequence, the remaining bits of the entry value corresponding to the index of the derivation operation used as input among the previous derivation operations; and
generating the file comprising the derived track and a reference to the at least one input.
2. The method of claim 1 , wherein the derived track comprises a derived track configuration data structure listing a set of derivation operations that can be used by the derived samples.
3. The method of claim 2 , wherein the derived track configuration data structure belongs to a sample entry of type ‘dtrk’.
4. The method of claim 3 , wherein the derived track comprises data for signalling whether an input of a derivation operation is defined in the derived track configuration data structure, or in the derived sample.
5. The method of claim 1 , wherein the derived track comprises data for signalling whether an input of a derivation operation of the sequence corresponds to an output of a previous derivation operation, or corresponds to an input of the list.
6. The method of claim 1 , wherein the derived track comprises data for signalling a maximum number of intermediate output(s) resulting from the performing of derivation operations.
7. The method of claim 1 , wherein the at least one input is an input sample belonging to an input track, or an input image item.
8. The method of claim 1 , wherein the index is a 1-based index of the previous derivation operation relatively to the derivation operation.
9. A method of generating of output samples, wherein the method comprises:
obtaining a file comprising a derived track comprising at least one derived sample, each derived sample comprising a sequence of derivation operations to be performed on a list of at least one input, the file comprising a reference to the at least one input;
wherein the derived track comprises an entry value having its most significant bit set to 1 for indicating that an input of a derivation operation is the output of one among the previous derivation operations in the sequence, the remaining bits of the entry value corresponding to the index of the derivation operation used as input among the previous derivation operations; and
generating the output samples by performing the sequence of derivation operations on the list of at least one input.
10. The method of claim 9 , wherein the index is a 1-based index of the previous derivation operation relatively to the derivation operation.
11. A device for generating a data file, wherein the device comprises circuitry configured for:
obtaining a derived track comprising at least one derived sample, each derived sample comprising a sequence of derivation operations to be performed on a list of at least one input;
wherein the derived track comprises an entry value having its most significant bit set to 1 for indicating that an input of a derivation operation is the output of one among the previous derivation operations in the sequence, the remaining bits of the entry value corresponding to the index of the derivation operation used as input among the previous derivation operations; and
generating the file comprising the derived track and a reference to the at least one input.
12. The method of claim 11 , wherein the index is a 1-based index of the previous derivation operation relatively to the derivation operation.
13. A device for generating of output samples, wherein the device comprises circuitry configured for:
obtaining a file comprising a derived track comprising at least one derived sample, each derived sample comprising a sequence of derivation operations to be performed on a list of at least one input, the file comprising a reference to the at least one input;
wherein the derived track comprises an entry value having its most significant bit set to 1 for indicating that an input of a derivation operation is the output of one among the previous derivation operations in the sequence, the remaining bits of the entry value corresponding to the index of the derivation operation used as input among the previous derivation operations; and
generating the output samples by performing the sequence of derivation operations on the list of at least one input.
14. The method of claim 13 , wherein the index is a 1-based index of the previous derivation operation relatively to the derivation operation.
15. A non-transitory computer-readable storage medium storing instructions of a computer program for implementing a method according to claim 1 .
16. A non-transitory computer-readable storage medium storing instructions of a computer program for implementing a method according to claim 9 .