US-12620370-B2 - Gamma adjustment for video display

Abstract

A display system adjusts gamma based on the brightness setting of a display screen, which may provide an improved viewer experience. A standard decoding gamma of 2.2 may no longer be the most comfortable for a user on modem, brighter displays. Using a higher gamma when the display screen is set to a high brightness can improve viewer experience. A display system determines a brightness setting of a screen and applies a gamma adjustment to content for display based on the brightness setting. If the display brightness changes, the gamma adjustment may also change.

Inventors

• Erwin Ben Bellers
• Steve ShawJong Liu
• Hsiangyao Shih

Assignees

• ROKU, INC.

Dates

Publication Date

20260505

Application Date

20240722

Claims (20)

1. 1 . A method comprising: receiving content for display on a display device, the content encoded at a first gamma value; determining a brightness setting related to an amount of light output by the display device; selecting a gamma adjustment for displaying content based on the brightness setting, the gamma adjustment corresponding to a second gamma value different from the first gamma value; decoding the content according to the first gamma value; applying the selected gamma adjustment to the content to generate gamma-adjusted content, wherein the selected gamma adjustment is applied to the content decoded according to the first gamma value; and displaying the gamma-adjusted content on the display device.
2. 2 . The method of claim 1 , wherein the second gamma value is greater than the first gamma value.
3. 3 . The method of claim 2 , wherein the first gamma value is 2.2, and the second gamma value is greater than 2.2.
4. 4 . The method of claim 1 , wherein the brightness setting is a first brightness setting and the gamma adjustment is a first gamma adjustment, the method further comprising: receiving a second brightness setting of the display device; and selecting a second gamma adjustment different from the first gamma adjustment, the second gamma adjustment corresponding to a third gamma value different from the second gamma value.
5. 5 . The method of claim 4 , wherein the second brightness setting is lower than the first brightness setting, and the third gamma value is equal to the first gamma value.
6. 6 . The method of claim 1 , further comprising: receiving a classification describing the received content; and selecting the gamma adjustment further based on the classification.
7. 7 . The method of claim 1 , wherein selecting the gamma adjustment comprises calculating the gamma adjustment using a formula having the brightness setting as a variable.
8. 8 . The method of claim 1 , wherein selecting the gamma adjustment comprises accessing a lookup table relating a plurality of brightness settings to a plurality of gamma adjustments.
9. 9 . The method of claim 1 , further comprising: retrieving a maximum brightness for the display device; wherein a maximum gamma adjustment is based on the maximum brightness for the display device.
10. 10 . A method comprising: receiving encoded content, the encoded content encoded at a first gamma value; receiving a brightness setting related to an amount of light output by a display device for displaying the content; selecting a gamma adjustment for the encoded content based on the brightness setting, the gamma adjustment corresponding to a second gamma value different from the first gamma value; applying the selected gamma adjustment to the encoded content to generate gamma-adjusted content; and transmitting the gamma-adjusted content to the display device, wherein the gamma-adjusted content is gamma-encoded, and the display device is configured to decode received content using the first gamma value.
11. 11 . The method of claim 10 , wherein applying the selected gamma adjustment to the content comprises: decoding the content according to the first gamma value; applying the selected gamma adjustment according to the second gamma value to the decoded content to generate gamma-adjusted content; and encoding the gamma-adjusted content according to the first gamma value.
12. 12 . The method of claim 10 , further comprising: receiving a maximum brightness for the display device; and selecting the gamma adjustment for the encoded content further based on the maximum brightness.
13. 13 . The method of claim 10 , wherein the gamma adjustment is a first gamma adjustment, the method further comprising: receiving a second brightness setting of the display device; and selecting a second gamma adjustment different from the first gamma adjustment, the second gamma adjustment corresponding to a third gamma value different from the second gamma value.
14. 14 . A device comprising: a display screen; and a processing component coupled to the display screen, the processing component to: receiving a first brightness setting of the display screen, the first brightness setting related to an amount of light output by the display screen; select a first gamma setting based on the first brightness setting; receive content encoded according to a gamma value different from the first gamma setting; apply the first gamma setting to the content to generate first gamma-adjusted content; output the first gamma-adjusted content to the display screen; receive a second brightness setting of the display screen; select a second gamma setting different from the first gamma setting; apply the second gamma setting to the content to generate second gamma-adjusted content; and output the second gamma-adjusted content to the display screen.
15. 15 . The device of claim 14 , wherein the processing component is a system on a chip (SoC) coupled to the display screen.
16. 16 . The device of claim 14 , wherein the processing component is further to: decode the content according to the gamma value; wherein applying the first gamma setting comprises adjusting brightness levels of the content decoded according to the gamma value.
17. 17 . The device of claim 14 , wherein the display screen has a maximum brightness, and the first gamma setting is further based on the maximum brightness of the display screen.
18. 18 . The device of claim 17 , wherein the maximum brightness is stored on a memory component of the device.
19. 19 . The device of claim 14 , wherein the content has an associated content classifier, and the first gamma setting is selected further based on the associated content classifier.
20. 20 . The device of claim 14 , wherein the gamma value is a first gamma value, the first gamma setting corresponds to a second gamma value different from the first gamma value, and the second gamma setting corresponds to a third gamma value different from the second gamma value.

Description

TECHNICAL FIELD This disclosure relates generally to display devices and systems, and more specifically, to techniques for adjusting display settings to improve viewer experience. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. FIG. 1 depicts two example brightness scales, according to some embodiments of the present disclosure. FIG. 2 illustrates different gamma curves relating values to display brightnesses, according to some embodiments of the present disclosure. FIG. 3 is a block diagram of exemplary electronic system to implement adaptive gamma according to some embodiments of the disclosure. FIG. 4 depicts a flow diagram for content handling and display that includes gamma encoding and gamma decoding, according to some embodiment of the disclosure. FIG. 5 depicts a flow diagram illustrating exemplary operations for content handling and display that includes gamma adjustment, according to some embodiment of the disclosure. FIG. 6 depicts a flow diagram illustrating exemplary operations for content handling and display that includes an alternate method for gamma adjustment, according to some embodiment of the disclosure. FIG. 7 depicts a flow diagram illustrating exemplary operations for selecting and performing a gamma adjustment based on overall display brightness, according to some embodiments of the disclosure. FIG. 8 depicts a flow diagram illustrating exemplary operations for adjusting gamma based on content, according to some embodiments of the disclosure. FIG. 9 depicts a flow diagram illustrating exemplary operations for adjusting gamma at a device connected to a separate display device, according to some embodiments of the disclosure. FIG. 10 depicts a block diagram of an exemplary computing device, according to some embodiments of the disclosure. DETAILED DESCRIPTION Overview Image data is typically broken down into smaller elements called pixels. Each pixel represents one color in a specific location of the screen. An image presented on a full high-definition screen (i.e., 1920×1080) will contain millions of these pixels. The pixels are often encoded in terms of an RGB triplet. In an RGB triplet, each component corresponds to red, green, or blue; each component can vary from zero to a defined maximum value. A higher value indicates a higher brightness for a particular color within the pixel. Display devices include various settings that can be tuned to improve user experience. Typical user-adjustable display settings, among others, include brightness, contrast, color temperature, and sharpness. Contrast describes the difference between the darkest and lightest parts of an image. A higher contrast enhances the distinction between light and dark areas, which can improve image depth and clarity. Color temperature describes the warmth or coolness of the display's color tone; a warm temperature causes images to appear more yellow, while a cool temperature causes images to appear more blue. Sharpness modifies the clarity and detail of the image. A higher sharpness can make edges appear crisper, but a high sharpness can also introduce visual artifacts. In the context of display settings, brightness describes the overall light output of the display. For example, in a liquid crystal display (LCD), the strength of the backlight impacts the brightness of the display. Display screens can often be dimmed based on user preference and/or environment. A higher brightness makes the screen lighter, which is suitable for well-lit environments, while lower brightness makes the screen darker, which is easier on viewers' eyes in darker rooms. Display brightness is often measured in candelas per square meter, also referred to as nits. Other measures of luminance may be used to objectively define brightness of a display. Some displays provide a user-adjustable gamma, also referred to as gamma correction. Gamma encoding or gamma correction defines the relationship between a pixel's numerical value and its actual luminance. Human perception of brightness is not linearly related to actual brightness, e.g., the number of photons emitted by a display. For example, when a digital camera captures an image, when twice the number of photons hit the camera sensor, the sensor receives twice the signal. The image data and the number of photons have a linear relationship. However, human eyes perceive twice the light (e.g., twice the number of photons) as being less than two times brighter, particularly at higher brightness levels. Said another way, human eyes are more sensitive to changes in darker tones than to changes in brighter tones. Because of how humans perceive light, in image and video encoding, it is