Distribution-point-based adaptive tone mapping

1. A method for tone mapping, the method comprising:

configuring, by at least one processor, at least one tone mapping function based on a measure of a distribution of luminance values within video data, the measure representing a luminance level I p at which a predetermined percentage of pixels of the video data have luminance values satisfying a threshold condition, wherein configuring includes adjusting the at least one tone mapping function such that when a luminance value of an input is less than the luminance level I p , a first tone mapping sub-function is applied to the input, and when the luminance value of the input is greater than the luminance level I p , a second tone mapping sub-function is applied to the input, such that an output of the at least one tone mapping function is dynamically changed based on the measure of the distribution of luminance values within the video data; and

generating a tone mapped video by applying the at least one configured tone mapping function to the video data.

2. The method of claim 1 , further comprising:

in response to determining that a maximum luminance level of the video data satisfies a tone mapping criterion, selecting to generate the tone mapped video and commencing the generation of the tone mapped video.

3. The method of claim 1 , wherein:

the at least one tone mapping function includes at least two tone mapping functions; and

the method further comprises:

determining a mixing ratio based on an amount of the video data that has luminance values within a predetermined range, wherein the mixing ratio represents a proportion of each of output of the at least two tone mapping functions, and

mixing the outputs of the at least two tone mapping functions according to the mixing ratio to generate the tone mapped video.

4. The method of claim 1 , further comprising:

calculating the measure of the distribution of luminance values within the video data.

5. The method of claim 1 , further comprising:

accessing metadata linked to the video data to obtain the measure of the distribution of luminance values within the video data.

6. The method of claim 1 , wherein the configuring of the at least one tone mapping function further comprises:

configuring the at least one tone mapping function based on metadata linked to the video data, wherein the metadata includes at least one of:

a maximum frame average luminance level, and

a maximum intensity of a mastering display.

7. The method of claim 1 , wherein the measure of a distribution of luminance values within the video data includes a measure of a distribution of luminance values within a group of frames of a same scene within the video data.

8. An apparatus for tone mapping, the apparatus comprising:

at least one processor configured to:

configure at least one tone mapping function based on a measure of a distribution of luminance values within video data, the measure representing a luminance level I p at which a predetermined percentage of pixels of the video data have luminance values satisfying a threshold condition, wherein configuring includes adjusting the at least one tone mapping function such that when a luminance value of an input is less than the luminance level I p , a first tone mapping sub-function is applied to the input, and when the luminance value of the input is greater than the luminance level I p , a second tone mapping sub-function is applied to the input, such that an output of the at least one tone mapping function is dynamically changed based on the measure of the distribution of luminance values within the video data; and

generate a tone mapped video by applying the at least one configured tone mapping function to the video data.

9. The apparatus of claim 8 , wherein the at least one processor is further configured to, in response to a determination that a maximum luminance level of the video data satisfies a tone mapping criterion, select to generate the tone mapped video and commence the generation of the tone mapped video.

10. The apparatus of claim 8 , wherein:

the at least one tone mapping function includes at least two tone mapping functions; and

the at least one processor is further configured to:

determine a mixing ratio based on an amount of the video data that has luminance values within a predetermined range, wherein the mixing ratio represents a proportion of each of output of the at least two tone mapping functions, and

mix the outputs of the at least two tone mapping functions according to the mixing ratio to generate the tone mapped video.

11. The apparatus of claim 8 , wherein the at least one processor is further configured to, calculate the measure of the distribution of luminance values within the video data.

12. The apparatus of claim 8 , wherein the at least one processor is further configured to, access metadata linked to the video data to obtain the measure of the distribution of luminance values within the video data.

13. The apparatus of claim 8 , wherein the at least one processor is further configured to configure the at least one tone mapping function based on metadata linked to the video data, wherein the metadata includes at least one of:

a maximum frame average luminance level, or

a maximum intensity of a mastering display.

14. The apparatus of claim 8 , wherein the measure of a distribution of luminance values within the video data includes a measure of a distribution of luminance values within a group of frames of a same scene within the video data.

15. A non-transitory computer readable medium embodying a computer program, the computer program comprising computer readable program code that, when executed, causes at least one processing device to:

configure at least one tone mapping function based on a measure of a distribution of luminance values within video data, the measure representing a luminance level I p at which a predetermined percentage of pixels of the video data have luminance values satisfying a threshold condition, wherein configuring includes adjusting the at least one tone mapping function such that when a luminance value of an input is less than the luminance level I p , a first tone mapping sub-function is applied to the input, and when the luminance value of the input is greater than the luminance level I p , a second tone mapping sub-function is applied to the input, such that an output of the at least one tone mapping function is dynamically changed based on the measure of the distribution of luminance values within the video data; and

generate a tone mapped video by applying the at least one configured tone mapping function to the video data.

16. The non-transitory computer readable medium of claim 15 , wherein the computer program further comprises computer readable program code that, when executed, causes the at least one processing device to in response to determining that a maximum luminance level of the video data satisfies a tone mapping criterion, select to generate the tone mapped video and commence the generation of the tone mapped video.

17. The non-transitory computer readable medium of claim 15 , wherein:

the at least one tone mapping function includes at least two tone mapping functions; and

the computer program further comprises computer readable program code that, when executed, causes the at least one processing device to:

determine a mixing ratio based on an amount of the video data that has luminance values within a predetermined range, wherein the mixing ratio represents a proportion of each of output of the at least two tone mapping functions, and

mix the outputs of the at least two tone mapping functions according to the mixing ratio to generate the tone mapped video.

18. The non-transitory computer readable medium of claim 15 , wherein the computer program further comprises computer readable program code that, when executed, causes the at least one processing device to calculate the measure of the distribution of luminance values within the video data.

19. The non-transitory computer readable medium of claim 15 , wherein the computer program further comprises computer readable program code that, when executed, causes the at least one processing device to access metadata linked to the video data to obtain the measure of the distribution of luminance values within the video data.

20. The non-transitory computer readable medium of claim 15 , wherein the computer program further comprises computer readable program code that, when executed causes, the at least one processing device to:

configure the at least one tone mapping function based on metadata linked to the video data, wherein the metadata includes at least one of:

a maximum frame average luminance level, or

a maximum intensity of a mastering display.