Signaling mechanisms for equal ranges and other DRA parameters for video coding

1. A method of encoding video data, comprising:

obtaining, at an encoding device, video data, the video data including parameters describing a piecewise linear function for dynamic range adjustment of colors in a portion of a video frame, wherein the parameters divide a range of input values to the piecewise linear function into a plurality of non-overlapping ranges, the plurality of non-overlapping ranges including a first range and a set of ranges, wherein the first range has a first length and each range of the set of ranges has a second length that is different from the first length;

generating a data structure for the parameters;

setting an indicator in the data structure to indicate that the plurality of non-overlapping ranges includes the set of ranges with each range having the second length;

based on the plurality of non-overlapping ranges including the set of ranges with each range having the second length, setting a first value in the data structure to indicate the second length for the set of ranges; and

generating encoded video data from the video data, wherein the data structure is included with the encoded video data.

2. The method of claim 1 , wherein the first value indicates the second length as a difference between an end value and a start value of each of the set of ranges.

3. The method of claim 1 , wherein the first value indicates the second length by indicating a difference between a fixed value and the second length.

4. The method of claim 1 , further comprising:

setting a second value in the data structure to indicate the first length.

5. The method of claim 1 , wherein the first range includes a first set of input values from a beginning of the range of input values, and wherein the set of ranges include a second set of input values, from the range of input values, that follow the first set of input values.

6. The method of claim 1 , wherein the parameters further include scale factors associated with each of the plurality of non-overlapping ranges, and further comprising:

adding the scale factors to the data structure.

7. The method of claim 1 , further comprising:

including the data structure in a Supplementary Enhancement Information (SEI) message, a slice header, or a parameter set.

8. An encoding device, comprising:

a memory configured to store video data, the video data including parameters describing a piecewise linear function for dynamic range adjustment of colors in a portion of a video frame, wherein the parameters divide a range of input values to the piecewise linear function into a plurality of non-overlapping ranges, the plurality of non-overlapping ranges including a first range and a set of ranges, wherein the first range has a first length and each range of the set of ranges has a second length that is different from the first length; and

a processor configured to:

generate a data structure for the parameters;

set an indicator in the data structure to indicate that the plurality of non-overlapping ranges includes the set of ranges with each range having the second length;

based on the plurality of non-overlapping ranges including the set of ranges with each range having the second length, set a first value in the data structure to indicate the second length for the set of ranges; and

generate encoded video data from the video data, wherein the data structure is included with the encoded video data.

9. The encoding device of claim 8 , wherein the first value indicates the second length as a difference between an end value and a start value of each of the set of ranges.

10. The encoding device of claim 8 , wherein the first value indicates the second length by indicating a difference between a fixed value and the second length.

11. The encoding device of claim 8 , wherein the processor is further configured to:

set a second value in the data structure to indicate the first length.

12. The encoding device of claim 8 , wherein the first range includes a first set of input values from a beginning of the range of input values, and wherein the set of ranges include a second set of input values, from the range of input values, that follow the first set of input values.

13. The encoding device of claim 8 , wherein the parameters further include scale factors associated with each of the plurality of non-overlapping ranges, and wherein the processor is further configured to:

add the scale factors to the data structure.

14. The encoding device of claim 8 , wherein the processor is further configured to:

include the data structure in a Supplementary Enhancement Information (SEI) message, a slice header, or a parameter set.

15. The encoding device of claim 8 , further comprising:

a camera for capturing video data.

16. The encoding device of claim 8 , wherein the encoding device comprises a mobile device.

17. A method for decoding video data, comprising:

obtaining encoded video data;

determining, for a portion of a video frame from the encoded video data, a data structure including parameters describing a piecewise linear function for dynamic range adjustment of colors in the portion of the video frame, wherein the parameters divide a range of input values to the piecewise linear function into a plurality of non-overlapping ranges;

determining, from an indicator in the data structure, that the plurality of non-overlapping ranges include a first range and a set of ranges, wherein the first range has a first length and each range of the set of ranges has a second length that is different from the first length;

determining, using a first value in the data structure, the second length, the first value being included in the data structure based on the plurality of non-overlapping ranges including the set of ranges with each range having the second length;

determining the first length using the data structure;

reconstructing the piecewise linear function using the first length, the second length, and scale factors associated with each of the plurality of non-overlapping ranges, wherein the scale factors are included in the data structure;

decoding the portion of the video frame; and

applying the piecewise linear function to the colors in the portion of the video frame to perform dynamic range adjustment.

18. The method of claim 17 , wherein the first value provides the second length and wherein a second value in the data structure provides the first length.

19. The method of claim 17 , wherein the first value indicates the second length by indicating a difference between a fixed value and the second length.

20. The method of claim 17 , wherein a second value in the data structure provides the first length, and further comprising:

determining from an index associated with the second value that the first range includes a first set of input values from a beginning of the range of input values, and wherein the set of ranges include a second set of input values, from the range of input values, that follow the first set of input values.

21. The method of claim 17 , wherein the parameters are included in a Supplementary Enhancement Information (SEI) message, a slice header, or a parameter set.

22. A decoding device, comprising:

a memory configured to store encoded video data; and

a processor configured to:

determine, for a portion of a video frame from the encoded video data, a data structure including parameters describing a piecewise linear function for dynamic range adjustment of colors in the portion of the video frame, wherein the parameters divide a range of input values to the piecewise linear function into a plurality of non-overlapping ranges;

determine, from an indicator in the data structure, that the plurality of non-overlapping ranges include a first range and a set of ranges, wherein the first range has a first length and each range of the set of ranges has a second length that is different from the second first length;

determine, using a first value in the data structure, the second length, the first value being included in the data structure based on the plurality of non-overlapping ranges including the set of ranges with each range having the second length;

determine the first length using information provided by the data structure;

reconstruct the piecewise linear function using the first length, the second length, and scale factors associated with each of the plurality of non-overlapping ranges, wherein the scale factors are included in the data structure;

decode the portion of the video frame; and

apply the piecewise linear function to the colors in the portion of the video frame to perform dynamic range adjustment.

23. The decoding device of claim 22 , wherein the first value provides the second length and wherein a second value in the data structure provides the first length.

24. The decoding device of claim 22 , wherein the first value indicates the second length by indicating a difference between a fixed value and the second length.

25. The decoding device of claim 22 , wherein a second value in the data structure provides the first length, and wherein the processor is further configured to:

determine from an index associated with the second value that the first range includes a first set of input values from a beginning of the range of input values, and wherein the set of ranges include a second set of input values, from the range of input values, that follow the first set of input values.

26. The decoding device of claim 22 , wherein the parameters are included in a Supplementary Enhancement Information (SEI) message, a slice header, or a parameter set.

27. The decoding device of claim 22 , further comprising:

a camera for capturing video data.

28. The decoding device of claim 22 , further comprising:

a display for displaying decoded video data.

29. The decoding device of claim 22 , wherein the decoding device comprises a mobile device.