Method and apparatus for obtaining parameters of a mapping curve

Abstract

To provide a method and apparatus for acquiring mapping curve parameters, configured to perform more accurate tone adjustment on display devices with different luminance, thereby obtaining improved flexibility.SOLUTION: A method includes the steps of: obtaining a first mapping curve parameter set and first maximum target system display luminance (1001); obtaining a display luminance parameter set (1002), the display luminance parameter set including maximum display luminance and / or minimum display luminance of a display device; obtaining an adjustment coefficient set (1003), the adjustment coefficient set corresponding to one or more parameters in the first mapping curve parameter set; and adjusting the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the adjustment coefficient set to obtain a second mapping curve parameter set (1004), the second mapping curve parameter set including one or more adjusted parameters.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202010366684.2, entitled "Method and Apparatus for Obtaining Parameters of Mapping Curve," filed with the State Intellectual Property Office of China on Thursday, April 30, 2020, and incorporated herein by reference in its entirety.

[0002] The present application relates to the field of image processing, and in particular to a method and apparatus for obtaining parameters of a mapping curve. [Background technology]

[0003] Dynamic range is used in many fields to describe the ratio of the maximum to minimum variable values. In digital images, dynamic range describes the ratio of the maximum grayscale value to the minimum grayscale value in the displayable range of the image. For the same scene in the real world, the real-world dynamic range is usually 10 -3 candela / m 2 (cd / m 2 ) to 10 6 cd / m 2 The dynamic image range for most color digital images today is between 0 and 255, which is referred to as high dynamic range (HDR).

[0004] Since there is a difference between the illumination range of the display device and the dynamic range in the real world, the dynamic range in the real world needs to be mapped to the illumination range of the display device, which is called dynamic range mapping. Dynamic range mapping can be applied to the adaptation between the HDR signal from the front end and the HDR display device in the back end. For example, the front end is 4000 cd / m 2The back-end HDR display device collects lighting signals at 500cd / m 2 It has an HDR display capability of 4000cd / m 2 Lighting signal of 500cd / m 2 Mapping to a display device of 100 cd / m is a high-to-low tone mapping (TM) process. Dynamic range mapping can also be applied to adapt between an SDR signal from the front end and an HDR display device at the back end. For example, the front end may be 100 cd / m 2 The lighting signal is collected at 1000 cd / m, and the HDR display capability of the back-end HDR display device is 2000 cd / m. 2 and 100 cd / m 2 Lighting signal of 2000cd / m 2 Mapping to a display device is a low-to-high TM process.

[0005] Currently, there are two dynamic range mapping methods: static mapping and dynamic mapping. In the static mapping method, a single piece of data is used to perform the entire TM process based on the same video content or the same hard disk content. In other words, the same mapping curve is usually used for various scenes. This method has the advantage that the image only needs to store less data and the processing procedure is simple. However, it has the disadvantage that information may be lost in some scenes because the same mapping curve is used for TM in all scenes. For example, if the mapping curve focuses on protecting bright areas, some details may be lost or even invisible in some extremely dark scenes. As a result, the image display effect is affected. In the dynamic mapping method, the mapping curve is dynamically adjusted for each scene or frame of the content based on specific regions. This method has the advantage that differentiated processing can be implemented for different scenes or frames, but it has the disadvantage that the image needs to store a large amount of data because related scene information needs to be stored in each frame or scene. Summary of the Invention

[0006] The embodiments of the present application provide a method and apparatus for obtaining parameters of a mapping curve to achieve high flexibility by performing more accurate tone adjustment on display devices with different luminances.

[0007] According to a first aspect, an embodiment of the present application provides a method for obtaining parameters of a mapping curve, the method including: obtaining a parameter set of a first mapping curve and a first maximum target system display luminance, where the parameter set of the first mapping curve corresponds to a first maximum target system display luminance and the parameter set of the first mapping curve includes one or more parameters related to the mapping curve; obtaining a display luminance parameter set, where the display luminance parameter set includes a maximum display luminance and / or a minimum display luminance of a display device; obtaining an adjustment coefficient set, where the adjustment coefficient set includes one or more adjustment coefficients corresponding to one or more parameters in the parameter set of the first mapping curve; and adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the adjustment coefficient set to obtain a parameter set of a second mapping curve, where the parameter set of the second mapping curve includes the one or more adjusted parameters.

[0008] In this application, one or more parameters related to the mapping curve are adjusted. In the adjustment process, the display capabilities of the backend are taken into account, so that more accurate tone adjustment can be performed on display devices with different brightness levels. This greatly improves flexibility and also achieves good presentation effects when the curve parameters are set appropriately.

[0009] In a possible implementation, adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain the parameter set of the second mapping curve includes: P a =P b +k×P Δ (1) calculating an adjusted first parameter according to equation (1), where the first parameter is any parameter in the parameter set of the first mapping curve, and the adjusted first parameter belongs to the parameter set of the second mapping curve; Including, P a represents the adjusted first parameter, and P b represents the first parameter, and P Δ represents an adjustment coefficient corresponding to the first parameter,

number

number

[0010] One or more parameters related to the mapping curve are adjusted based on the adjustment coefficient. In the adjustment process, the display capabilities of the backend are taken into account, so that more accurate tone adjustment can be performed on display devices with different brightness. This greatly improves flexibility and also achieves good presentation effects when the curve parameters are properly set.

[0011] In a possible implementation, before adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of the second mapping curve, the method further includes obtaining one or more of a maximum luminance, a minimum luminance, an average value, and a variation range of the content to be displayed, and obtaining an intermediate value of the first parameter based on one or more of the maximum display luminance, the minimum display luminance, the maximum luminance, the minimum luminance, the average value, and the variation range, where the first parameter is any parameter in the parameter set of the first mapping curve. P a =(1-w)×P b +w×P m (2) calculating an adjusted first parameter according to equation (2), where the adjusted first parameter belongs to a parameter set of a second mapping curve; a represents the adjusted first parameter, and P b represents the first parameter,

number

number

[0012] One or more parameters related to the mapping curve are obtained by using multiple parameters in a weighted manner. In the adjustment process, the display capabilities of the backend are taken into account, so that more accurate tone adjustment can be performed on display devices with different brightness. This greatly improves flexibility and also achieves good presentation effects when the curve parameters are set appropriately.

[0013] In a possible implementation, after the step of calculating the adjusted first parameter according to the formula, the method further includes a step of obtaining a first mapping curve based on the adjusted first parameter and parameters in the parameter set of the first mapping curve other than the first parameter, and a step of continuing to adjust the first parameter if the luminance of the content to be displayed obtained by performing tone mapping based on the first mapping curve is higher than the original luminance of the content to be displayed, or a step of analyzing the adjusted first parameter according to a predetermined rule, and a step of continuing to adjust the first parameter if the adjusted first parameter complies with the predetermined rule.

[0014] The parameters related to the mapping curve are fine-tuned one by one to improve the accuracy of the parameters of the mapping curve.

[0015] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain the parameter set of the second mapping curve includes:

number

[0016] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain the parameter set of the second mapping curve includes:

number

[0017] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain the parameter set of the second mapping curve includes:

number

[0018] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, adjusting one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain the parameter set of the second mapping curve includes:

number

[0019] In a possible implementation, the step of obtaining a parameter set of the first mapping curve and a first maximum target system display luminance includes a step of obtaining a parameter set of the first mapping curve and a first maximum target system display luminance from dynamic metadata of the content to be displayed, or a step of obtaining a parameter set of the first mapping curve from dynamic metadata, and a step of obtaining a first maximum target system display luminance corresponding to the parameter set of the first mapping curve based on a specific correspondence.

[0020] In a possible implementation, obtaining the set of adjustment coefficients includes obtaining the set of adjustment coefficients from dynamic metadata of the content to be displayed, or obtaining the set of adjustment coefficients based on pre-set values.

[0021] In a possible implementation, the step of obtaining the set of adjustment factors includes directly reading one or more adjustment factors, or obtaining an adjustment mode and obtaining one or more adjustment factors corresponding to the adjustment mode.

[0022] In a possible implementation, the step of obtaining the display brightness parameter set includes a step of obtaining the display brightness parameter set based on device information, or a step of obtaining the display brightness parameter set based on preset information.

[0023] In a possible implementation, after the step of adjusting one or more parameters in the parameter set of the first mapping curve based on the display brightness parameter set, the first maximum target system display brightness, and the adjustment coefficient set to obtain a parameter set of the second mapping curve, the method further includes a step of obtaining a mapping curve based on the one or more adjusted parameters in the parameter set of the second mapping curve.

[0024] According to a second aspect, an embodiment of the present application provides an apparatus for processing content to be displayed. The apparatus includes an acquisition module and a processing module. The acquisition module is configured to: acquire a parameter set of a first mapping curve and a first maximum target system display luminance, where the parameter set of the first mapping curve corresponds to a first maximum target system display luminance and includes one or more parameters related to the mapping curve; acquire a display luminance parameter set, where the display luminance parameter set includes a maximum display luminance and / or a minimum display luminance of a display device; and acquire an adjustment coefficient set, where the adjustment coefficient set includes one or more adjustment coefficients corresponding to one or more parameters in the parameter set of the first mapping curve. The processing module is configured to adjust one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the adjustment coefficient set to acquire a parameter set of a second mapping curve, where the parameter set of the second mapping curve includes the one or more adjusted parameters.

[0025] In a possible implementation, the processing module specifically: Pa = Pb + k × PΔ (1) configured to calculate an adjusted first parameter according to Equation (1), where the first parameter is any parameter in the parameter set of the first mapping curve, and the adjusted first parameter belongs to the parameter set of the second mapping curve; and a represents the adjusted first parameter, and P b represents the first parameter, and P Δ represents an adjustment coefficient corresponding to the first parameter,

number

number

[0026] In a possible implementation, the obtaining module is further configured to obtain one or more of a maximum luminance, a minimum luminance, an average value, and a variation range of the content to be displayed, and obtain an intermediate value of a first parameter based on one or more of the maximum display luminance, the minimum display luminance, the maximum luminance, the minimum luminance, the average value, and the variation range, where the first parameter is any parameter in the parameter set of the first mapping curve. P a =(1-w)×P b +w×P m (2) and calculating an adjusted first parameter according to Equation (2), where the adjusted first parameter belongs to a parameter set of the second mapping curve; and P a represents the adjusted first parameter, and P b represents the first parameter,

number

number

[0027] In a possible implementation, the processing module is further configured to obtain a first mapping curve based on the adjusted first parameter and parameters in the parameter set of the first mapping curve other than the first parameter, and to continue adjusting the first parameter if the luminance of the content to be displayed obtained by performing tone mapping based on the first mapping curve is higher than the original luminance of the content to be displayed, or to analyze the adjusted first parameter according to a predetermined rule, and to continue adjusting the first parameter if the adjusted first parameter complies with the predetermined rule.

[0028] In a possible implementation, the processing module is particularly configured to:

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[0029] In a possible implementation, the processing module is particularly configured to:

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[0030] In a possible implementation, the processing module is particularly configured to:

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[0031] In a possible implementation, the processing module is particularly configured to:

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[0032] In a possible implementation, the acquisition module is specifically configured to acquire a parameter set of a first mapping curve and a first maximum target system display luminance from dynamic metadata of the content to be displayed, or to acquire a parameter set of a first mapping curve from the dynamic metadata and acquire a first maximum target system display luminance corresponding to the parameter set of the first mapping curve based on a specific correspondence.

[0033] In a possible implementation, the acquisition module is specifically configured to acquire the set of adjustment coefficients from dynamic metadata of the content to be displayed, or to acquire the set of adjustment coefficients based on pre-defined values.

[0034] In a possible implementation, the acquisition module is specifically configured to directly read one or more adjustment factors, or to acquire an adjustment mode and acquire one or more adjustment factors corresponding to the adjustment mode.

[0035] In a possible implementation, the acquisition module is specifically configured to acquire the display brightness parameter set based on device information, or to acquire the display brightness parameter set based on preset information.

[0036] In a possible implementation, the obtaining module is further configured to obtain the mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0037] According to a third aspect, an embodiment of the present application provides a terminal device including one or more processors and a memory, the memory configured to store one or more programs, the one or more programs, when executed by the one or more processors, enabling the one or more processors to perform the method according to any one of the first aspect.

[0038] According to a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing program code, the program code including instructions used to perform some or all of the steps of any of the methods in the first aspect.

[0039] According to a fifth aspect, an embodiment of the present application provides a computer program product which, when run on a computer, enables the computer to perform some or all of the steps of any of the methods in the first aspect.

[0040] It should be understood that the technical solutions in the second to fifth aspects of the present application are consistent with the technical solutions in the first aspect of the present application, and the beneficial effects achieved in the aspects and corresponding feasible implementations are similar, and the details will not be described again. [Brief explanation of the drawings]

[0041] In order to describe the technical solutions and background in the embodiments of the present application more clearly, the following briefly describes the accompanying drawings used in the embodiments or background of the present application.

[0042] [Figure 1] FIG. 1 is a diagram of an example of dynamic range mapping for image processing in the real world.

[0043] [Figure 2] FIG. 2 is a schematic diagram of an example of a curve of a PQ optical-to-electrical transfer function.

[0044] [Figure 3] 1 is a schematic diagram of an example of a curve of an HLG optical-to-electrical transfer function.

[0045] [Figure 4] FIG. 1 is a schematic diagram of an example of an SLF optical-to-electrical transfer function curve.

[0046] [Figure 5] FIG. 1 is a schematic diagram of an example of an S-shaped curve.

[0047] [Figure 6] FIG. 2 is a schematic diagram of an example of a Bezier curve.

[0048] [Figure 7] FIG. 1 is a schematic diagram of an example of an S-shaped curve.

[0049] [Figure 8] 1 is a schematic block diagram of an example of a video processing system to which an embodiment of the present application may be applied;

[0050] [Figure 9] 9 is a schematic diagram of an example of the structure of a terminal device 900. FIG.

[0051] [Figure 10] 1 is a flowchart of an embodiment of a method for obtaining parameters of a mapping curve according to the present application;

[0052] [Figure 11] 11 is a structural block diagram of a video processing device 1100 configured to implement an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0053] The following describes embodiments of the present application with reference to the accompanying drawings of embodiments of the present application. In the following description, reference is made to the accompanying drawings, which form a part of this disclosure and which show, by way of illustration, specific aspects of the embodiments of the present application or in which the embodiments of the present application may be used. It should be understood that the embodiments of the present application may be used in other ways and may include structural or logical changes not depicted in the accompanying drawings. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present application is defined by the appended claims. For example, it should be understood that the disclosure relating to a described method may also apply to a corresponding device or system for performing the method, and vice versa. For example, when one or more particular method steps are described, a corresponding device may include one or more units, such as functional units, for performing one or more of the described method steps (e.g., one unit performing one or more steps, or multiple units performing one or more of the multiple steps), even if such one or more units are not explicitly described or shown in the accompanying drawings. Additionally, for example, if a particular apparatus is described based on one or more units, such as functional units, a corresponding method may include a step for implementing the functionality of the one or more units (e.g., a step for implementing the functionality of the one or more units, or multiple steps, each for implementing the functionality of one or more units in multiple units), even if such step or steps are not explicitly described or shown in the accompanying drawings. Furthermore, it should be understood that features of various exemplary embodiments and / or aspects described herein may be combined with each other, unless expressly stated otherwise.

[0054] The terms used in the embodiments of the present application are only used to describe specific embodiments of the present application, and are not intended to limit the present application. In the following, some related concepts in the embodiments of the present application will first be briefly described.

[0055] 1. Dynamic range

[0056] Dynamic range is used in many fields to refer to the ratio of the maximum to minimum variable values. In digital images, dynamic range refers to the ratio of the maximum to the minimum grayscale value in the displayable range of the image.

[0057] In nature, the luminance of a night scene under a starry sky is approximately 0.001 cd / m 2 and the brightness of the sun itself is at most 10 9 cd / m 2 and the dynamic range is 10 9 / 0.001=10 12 cd / m 2 However, in the real world, the brightness of the sun and the brightness of the starlight are not captured simultaneously. Therefore, in the same real-world scene, the dynamic range in the real world is usually 10 -3 cd / m 2 From 10 6 cd / m 2 The range is between 0 and 255, which is called high dynamic range (HDR). In most color digital images, the grayscale of the red (R), green (G), and blue (B) channels is stored by using one byte each. That is, the range of the grayscale of the R, G, and B channels is 0-255. 0-255 is the dynamic range of the image, which is called low dynamic range (LDR).

[0058] 2. Optical-electro transfer function (OETF)

[0059] The image processing of a digital camera actually maps the high dynamic range of the real world to the low dynamic range of a digital image. Figure 1 shows an example of the dynamic range mapping of image processing in the real world. As shown in Figure 1, in the real world, in addition to the luminance of starlight and the luminance of the sun, 2 Moonlight brightness of 100 cd / m 2 Indoor lighting brightness: 500cd / m 2 Outdoor brightness in cloudy weather of 2000 cd / m 2 In the real world, the luminance of a bright, sunny outdoor area is 100 cd / m 2 to 2000 cd / m 2 1cd / m2 brightness range and memory mode for display devices 2 to 200 cd / m 2 There is a mapping relationship between the luminance range up to .

[0060] Because the luminance corresponding to the storage mode of a display device cannot reach the high luminance in the real world, an optical-electro transfer function (OETF) is needed to express the luminance in the real world as the luminance corresponding to the storage mode of a display device. For example, if the luminance in the real world is 10000 cd / m 2 If the display device stores luminance information using 10 bits, the maximum value that can be stored in this storage mode is 1023. Therefore, 10000 cd / m 2 can be represented as 1023.

[0061] The previous display device was the cathode ray tube (CRT) display, and the optical-electrical transfer function of the CRT display is the gamma function, which is defined in ITU-R Recommendation BT.1886.

number

[0062] The illuminance range of display devices is continuously increasing with display device upgrades. Existing HDR displays have an illuminance of 600cd / m 2 while the illuminance of high-end HDR displays is 2000cd / m 2 Therefore, an improved optical-electrical transfer function is needed to accommodate the upgrade of display devices. Currently, there are three common types of optical-electrical transfer functions: perception quantization (PQ) optical-electrical transfer function, hybrid log-gamma (HLG) optical-electrical transfer function, and scene luminance fidelity (SLF) optical-electrical transfer function.

[0063] (1) Different from the traditional gamma function, a PQ optical-electrical transfer function is proposed based on a model of contrast perception of the human eye under different luminances. The PQ optical-electrical transfer function represents the relationship of the transformation from the linear signal value of a pixel in an image frame to the nonlinear signal value in the PQ domain. Figure 2 is a schematic diagram of an example of the curve of the PQ optical-electrical transfer function. The PQ optical-electrical transfer function can be expressed as the following equation:

number

[0064] The parameters corresponding to R, G, and B in the above formula are:

number

number

number

number

number

number

[0065] (2) The HLG optical-electrical transfer function is obtained by improving the conventional gamma curve. The HLG optical-electrical transfer function uses the conventional gamma curve in the low segment and supplements it with a logarithmic curve in the high segment. The HLG optical-electrical transfer function represents the conversion relationship from the linear signal values ​​of pixels in an image frame to nonlinear signal values ​​in the HLG domain. Figure 3 is a schematic diagram of an example curve of the HLG optical-electrical transfer function. The HLG optical-electrical transfer function can be expressed as the following equation:

number

[0066] L represents the linear signal value of a pixel in the image frame, with the value range of L being [0,12], L' represents the nonlinear signal value in the HLG domain, with the value range of L' being [0,1], and a, b, and c are all HLG optical-to-electrical transfer coefficients, where a=0.17883277, b=0.28466892, and c=0.55991073.

[0067] (3) The SLF optical-electrical transfer function is obtained based on the luminance distribution in the HDR scenario, assuming that the optical characteristics of the human eye are satisfied. The SLF optical-electrical transfer function represents the conversion relationship from the linear signal value of the pixel of the image frame to the nonlinear signal value in the SLF domain. Figure 4 is a schematic diagram of an example of the curve of the SLF optical-electrical transfer function. The SLF optical-electrical transfer function can be expressed as the following equation:

number

[0068] The parameters corresponding to R, G, and B in the above formula are:

number

[0069] 3. Dynamic Range Mapping

[0070] Dynamic range mapping can be applied to adapt between the HDR signal from the front end and the HDR display device at the back end. For example, the front end may be 4000 cd / m 2 The back-end HDR display device collects lighting signals at 500cd / m 2 It has an HDR display capability of 4000cd / m 2 Lighting signal of 500cd / m 2Mapping to a display device of 100 cd / m is a high-to-low tone mapping (TM) process. Dynamic range mapping can also be applied to adapt between an SDR signal from the front end and an HDR display device at the back end. For example, the front end may be 100 cd / m 2 The lighting signal is collected at 1000 cd / m, and the HDR display capability of the back-end HDR display device is 2000 cd / m. 2 and 100 cd / m 2 Lighting signal of 2000cd / m 2 Mapping to a display device is a low-to-high TM process.

[0071] Currently, there are two dynamic range mapping methods: static mapping and dynamic mapping. In the static mapping method, a single piece of data is used to perform the entire TM process based on the same video content or the same hard disk content. That is, the same mapping curve for different scenes usually exists. This method has the advantage that the video only needs to store less data and the processing procedure is simple. However, it has the disadvantage that information may be lost in some scenes because the same mapping curve is used for TM in all scenes. For example, if the mapping curve focuses on protecting bright areas, some details may be lost or even invisible in some extremely dark scenes. As a result, the video display effect is affected. In the dynamic mapping method, the mapping curve is dynamically adjusted for each scene or frame of the content based on specific regions. This method has the advantage that differentiated processing can be implemented for different scenes or frames, but it has the disadvantage that the video needs to store a large amount of data because related scene information needs to be stored in each frame or scene.

[0072] 4.TM technology

[0073] (1) TM processing based on S-shaped curves

[0074] FIG. 5 is a schematic diagram of an example of an S-shaped curve.

[0075] (2) TM processing based on Bezier curves

[0076] FIG. 6 is a schematic diagram of an example of a Bezier curve.

[0077] (3) TM processing based on the S-shaped curve perceived by the human eye

[0078] 7 is a schematic diagram of an example of an S-shaped curve. The optical-to-electrical transfer function corresponding to the S-shaped curve can be expressed as:

number

[0079] Each of L and L' is a normalized electrical or optical signal, both L and L' have a value range of [0,1], a has a value range of [0,1], b has a value range of [0,1], and p, n, and m have a value range of [0,N], where N is a rational number greater than 0.1, and k1, k2, and k3 are all rational numbers.

[0080] 5. Dynamic Metadata

[0081] The front end (video acquisition and / or production) includes parameters related to the mapping curve in the dynamic metadata sent to the back end (video display).

[0082] (1) S-shaped curve

[0083] The definition of dynamic metadata related to the S-curve proposed in ST2094-10 includes not only video statistics such as maximum luminance value (maximum value of PQ-encoded maxRGB), minimum luminance value (minimum value of PQ-encoded maxRGB), and average luminance value (average value of PQ-encoded maxRGB), but also parameters related to the S-curve, such as tone mapping offset, tone mapping gain, and tone mapping gamma, for directly generating the S-curve.

[0084] However, the method of generating the aforementioned parameters is fixed, and as a result, the parameters included in the dynamic metadata cannot provide greater flexibility for curve generation.

[0085] (2) Bezier curve

[0086] The definition of dynamic metadata related to Bezier curves proposed in ST2094-40 includes histogram information (distribution of MaxRGB) and parameters related to Bezier curves (Bezier curve anchors) for directly generating Bezier curves.

[0087] In addition, the ST2094 series of standards includes a maximum (peak) target system display luminance (targeted_system_display_maximum_luminance, TSDAPL).

[0088] The above parameters correspond to TSDAPL when generated in the front end, but the same curve is used for different display devices in the back end, which results in the inability to achieve the best display effect.

[0089] (3)S-shaped curve

[0090] The dynamic metadata may include video statistics such as maximum, minimum, and average luminance values, or may include parameters related to the S-curve such as p, m, a, b, n, K1, K2, and K3.

[0091] The following describes a system architecture applied to an embodiment of the present application. Figure 8 is a schematic block diagram of an example of a video processing system applied to an embodiment of the present application. As shown in Figure 8, the video processing system is divided into a front end and a back end. The front end includes a video acquisition and / or production module, and the back end includes an HDR display module and / or an SDR display module. The front end pre-processes the acquired video data and transmits the pre-processed data to the back end. In addition, the front end maintains dynamic metadata of the video data. The back end performs enhancement processing on image frames in the video based on the video data combined with the corresponding dynamic metadata to obtain images with excellent color, excellent brightness, excellent contrast, and the like, and displays the images.

[0092] In this application, the front end and the back end may be different physical devices independent of each other. For example, the front end may be a device with a video capture function, such as a video camera, a camera, or an image rendering machine, and the back end may be a device with a video playback function, such as a mobile phone, a tablet, a set-top box, or a television. In this case, a wireless connection or a wired connection may be established between the front end and the back end. The wireless connection may use technologies such as long-term evolution (LTE), fifth-generation (5G) mobile communications, and future mobile communications. The wireless connection may further include technologies such as wireless fidelity (Wi-Fi), Bluetooth, and near-field communication (NFC). The wired connection may include an Ethernet connection, a local area network connection, and the like, but is not limited thereto. In the present application, the front-end functionality and the back-end functionality may further be integrated into the same physical device, for example, a mobile phone, a tablet, a set-top box, a television, or an image drawing machine with video shooting capabilities. In the present application, a part of the front-end functionality and a part of the back-end functionality may alternatively be integrated into the same physical device, but this is not particularly limited.

[0093] The aforementioned device integrating front-end and back-end functions may be deployed indoors or outdoors, handheld, or on land, including on a vehicle, on water (e.g., on a ship), or in the air (e.g., on an airplane, balloon, or satellite). The terminal device may be a mobile phone, a tablet computer (pad), a wearable device with wireless communication capability (e.g., a smart watch), a location tracker with positioning capability, a computer with wireless transmission / reception capability, a virtual reality (VR) device, an augmented reality (AR) device, a wireless device in industrial control, a wireless device in self-driving, a wireless device in remote medical care, a wireless device in a smart grid, a wireless device in transportation safety, a wireless device in a smart city, a wireless device in a smart home, or the like. This is not a limitation in the present application.

[0094] FIG. 9 is a schematic diagram of an example of the structure of a terminal device 900. As shown in FIG. 9, the terminal device 900 includes components such as an application processor 901, a microcontroller unit (MCU) 902, a memory 903, a modem 904, a radio frequency (RF) module 905, a wireless fidelity (Wi-Fi) module 906, a Bluetooth module 907, sensors 908, input / output (I / O) devices 909, and a positioning module 910. These components may communicate with each other via one or more communication buses or signal cables. The communication bus or signal cable may be a CAN bus as provided herein. Those skilled in the art will understand that the terminal device 900 may include more or fewer components than those shown in the figure, some components may be combined, or components may be arranged in a different manner.

[0095] The components of the terminal device 900 will be specifically described below with reference to FIG.

[0096] The application processor 901 is the control center of the terminal device 900 and is connected to the components of the terminal device 900 via various interfaces and buses. In some embodiments, the processor 901 may include one or more processing units.

[0097] The memory 903 stores computer programs such as the operating system 911 and applications 912 shown in FIG. 9 . The application processor 901 is configured to execute the computer programs in the memory 903 and implement functions defined by the computer programs. For example, the application processor 901 executes the operating system 911 to implement various functions of the operating system on the terminal device 900. The memory 903 also stores data other than computer programs, such as data generated during the operation of the operating system 911 and applications 912. The memory 903 is a non-volatile storage medium and generally includes an internal memory and an external memory. The internal memory includes, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a cache, or the like. The external memory includes, but is not limited to, a flash memory, a hard disk, a compact disc, a universal serial bus (USB), a flash drive, or the like. The computer program is typically stored in the external memory. Before executing a computer program, the processor loads the program from external memory into internal memory.

[0098] The memory 903 may be separate and connected via a bus to the application processor 901. Alternatively, the memory 903 and the application processor 901 may be integrated into a chip subsystem.

[0099] The MCU 902 is a coprocessor configured to acquire and process data from the sensors 908. The MCU 902 has lower processing power and power consumption than the application processor 901, but has an "always on" feature and can continuously collect and process sensor data when the application processor 901 is in sleep mode to ensure normal operation of the sensors with extremely low power consumption. In one embodiment, the MCU 902 can be a sensor hub chip. The sensors 908 can include a light sensor and a motion sensor. Specifically, the light sensor can include an ambient light sensor and a proximity sensor. The ambient light sensor can adjust the brightness of the display 9091 based on the brightness of the ambient light. The proximity sensor can power off the display screen when the terminal device 900 is close to the ear. As a type of motion sensor, an accelerometer sensor can detect acceleration values ​​in various directions (generally, three axes) and can detect the value and direction of gravity when the accelerometer sensor is stationary. The sensors 908 may further include other sensors, such as a gyroscope, a barometer, a hygrometer, a thermometer, or an infrared sensor, which will not be described in detail herein. The MCU 902 and the sensors 908 may be integrated on the same chip or may be separate components connected via a bus.

[0100] The modem 904 and the radio frequency module 905 constitute the communication subsystem of the terminal device 900 and are configured to implement the main functions of a standard protocol for wireless communication. The modem 904 is configured to perform encoding / decoding, signal modulation / demodulation, equalization, and the like. The radio frequency module 905 is configured to receive and transmit radio signals. The radio frequency module 905 includes, but is not limited to, an antenna, at least one amplifier, a coupler, a duplexer, and the like. The radio frequency module 905 cooperates with the modem 904 to implement wireless communication functions. The modem 904 may function as an independent chip or may be combined with other chips or circuits to form a system-level chip or integrated circuit. These chips or integrated circuits may be applied to all terminal devices that implement wireless communication functions, including mobile phones, computers, notebook computers, tablet computers, routers, wearable devices, vehicles, home appliances, and the like.

[0101] The terminal device 900 may further perform wireless communication by using a Wi-Fi module 906, a Bluetooth module 907, or the like. The Wi-Fi module 906 is configured to provide the terminal device 900 with network access conforming to Wi-Fi-related standard protocols. The terminal device 900 may access a Wi-Fi access point by using the Wi-Fi module 906 to access the Internet. In some other embodiments, the Wi-Fi module 906 may alternatively function as a Wi-Fi wireless access point and provide Wi-Fi network access to other terminal devices. The Bluetooth module 907 is configured to implement short-range communication between the terminal device 900 and other terminal devices (e.g., a mobile phone or a smart watch). The Wi-Fi module 906 in this embodiment of the present application may be an integrated circuit, a Wi-Fi chip, or the like. The Bluetooth module 907 may be an integrated circuit, a Bluetooth chip, or the like.

[0102] The positioning module 910 is configured to determine the geographical position of the terminal device 900. It can be understood that the positioning module 910 can specifically be a receiver of a positioning system, such as a global positioning system (GPS), a Beidou satellite navigation system, or a Russian GLONASS.

[0103] The Wi-Fi module 906, the Bluetooth module 907, and the positioning module 910 may be separate chips or integrated circuits, or may be integrated together. For example, in one embodiment, the Wi-Fi module 906, the Bluetooth module 907, and the positioning module 910 may be integrated on the same chip. In other embodiments, the Wi-Fi module 906, the Bluetooth module 907, the positioning module 910, and the MCU 902 may alternatively be integrated on the same chip.

[0104] The input / output devices 909 include, but are not limited to, a display 9091, a touch screen 9092, audio circuitry 9093, and the like.

[0105] The touch screen 9092 may collect touch events (e.g., operations performed by the user on or near the touch screen 9092 by using a finger or any suitable object, such as a stylus pen) of the user of the terminal device 900 on or near the touch screen 9092 and transmit the collected touch events to other components (e.g., the application processor 901). An operation performed by the user near the touch screen 9092 may be referred to as a floating touch. Through the floating touch, the user may select, move, or drag a target (e.g., an icon) without directly touching the touch screen 9092. In addition, the touch screen 9092 may be implemented using multiple types of touch screens, such as resistive, capacitive, infrared, and surface acoustic wave types.

[0106] The display (also referred to as a display screen) 9091 is configured to display information input by a user or information displayed by a user. The display 9091 may be configured, for example, in the form of a liquid crystal display or an organic light-emitting diode. The touchscreen 9092 may cover the display 9091. After detecting a touch event, the touchscreen 9092 transmits the touch event to the application processor 901 to determine the type of the touch event. The application processor 901 may then provide a corresponding visual output on the display 9091 based on the type of touch event. In FIG. 9 , the touchscreen 9092 and the display 9091 function as two independent components to implement the input and output functions of the terminal device 900. However, in some embodiments, the touchscreen 9092 and the display 9091 may be integrated to implement the input and output functions of the terminal device 900. In addition, the touchscreen 9092 and the display 9091 may be disposed on the front side of the terminal device 900 in a full-panel format to implement a bezel-less structure.

[0107] The audio circuit 9093, speaker 9094, and microphone 9095 may provide an audio interface between a user and the terminal device 900. The audio circuit 9093 may transmit electrical signals into which received audio data has been converted to the speaker 9094. The speaker 9094 converts the electrical signals into sound signals for output. In addition, the microphone 9095 converts collected sound signals into electrical signals, and the audio circuit 9093 receives the electrical signals and converts the electrical signals into audio data, and then transmits the audio data to, for example, another terminal device or outputs the audio data to the memory 903 for further processing by using the modem 904 and the radio frequency module 905.

[0108] In addition, the terminal device 900 may further have a fingerprint recognition function. For example, the fingerprint collection component may be configured on the back side of the terminal device 900 (e.g., below the rear camera), or the fingerprint collection component may be configured on the front side of the terminal device 900 (e.g., below the touchscreen 9092). In another example, the fingerprint collection component may be configured within the touchscreen 9092 to implement the fingerprint recognition function. Specifically, the fingerprint collection component may be integrated with the touchscreen 9092 to implement the fingerprint recognition function of the terminal device 900. In this case, the fingerprint collection component is configured within the touchscreen 9092, and may be part of the touchscreen 9092 or configured within the touchscreen 9092 in other ways. The main part of the fingerprint collection component in this embodiment of the present application is a fingerprint sensor. The fingerprint sensor may use any type of detection technology, including, but not limited to, optical detection technology, capacitive detection technology, piezoelectric detection technology, ultrasonic detection technology, or the like.

[0109] Furthermore, the operating system 911 held in the terminal device 900 may be iOS®, Android®, Microsoft®, or other operating systems, which is not limited in this embodiment of the present application.

[0110] A terminal device 900 running the Android® operating system is used as an example. The terminal device 900 may be logically divided into a hardware layer, an operating system 911, and an application layer. The hardware layer includes hardware resources such as the aforementioned application processor 901, MCU 902, memory 903, modem 904, Wi-Fi module 906, sensor 908, and positioning module 910. The application layer includes one or more applications, such as application 912. The application 912 may be any type of application, such as a social application, an e-commerce application, or a browser. The operating system 911 is a computer program that functions as software middleware between the hardware layer and the application layer and manages and controls hardware and software resources.

[0111] In one embodiment, the operating system 911 includes a kernel, a hardware abstraction layer (HAL), libraries and runtime, and a framework. The kernel is configured to provide basic system components and services, such as power management, memory management, thread management, and hardware drivers. The hardware drivers include Wi-Fi drivers, sensor drivers, positioning module drivers, and the like. The hardware abstraction layer encapsulates kernel driver programs, provides an interface to the framework, and hides underlying implementation details. The hardware abstraction layer runs in user space, and the kernel driver programs run in kernel space.

[0112] The libraries and runtimes, also referred to as runtime libraries, provide library files and an execution environment required for an executable program to run. In one embodiment, the libraries and runtimes include the Android runtime (ART), libraries, and a scenario package runtime. The ART is a virtual machine or virtual machine instance that can convert application bytecode into machine code. The libraries are program libraries that provide support for the executable program during operation, including a browser engine (such as WebKit), a script execution engine (e.g., a JavaScript engine), a graphics processing engine, and the like. The scenario package runtime is the operating environment of the scenario package, and mainly includes a page execution environment (page context) and a script execution environment (script context). The page execution environment calls corresponding libraries to parse page code in HTML, CSS, or other formats, and the script execution environment calls corresponding function libraries to parse and execute code or executable files implemented in a scripting language such as JavaScript.

[0113] The framework is configured to provide various basic common components and services such as window management and position management for application programs in the application layer. In one embodiment, the framework includes a geofence service, a policy service, a notification manager, and the like.

[0114] All of the functions of the components in the operating system 911 described above may be implemented by the application processor 901 by executing programs stored in the memory 903 .

[0115] Those skilled in the art will appreciate that terminal device 900 may include fewer or more components than those shown in FIG. 9, and that the terminal device shown in FIG. 9 includes only components that are more relevant to the implementations disclosed herein.

[0116] The solution in the embodiment of the present application will be described in detail below.

[0117] 10 is a flowchart of an embodiment of a method for obtaining parameters of a mapping curve according to the present application. As shown in FIG. 10, process 1000 may be applied to the video processing system shown in FIG. 8 or the terminal device shown in FIG. 9. The execution entity of process 1000 includes a back end in the terminal device or the video processing system. Process 1000 is described as a series of steps or operations. It should be understood that the steps or operations of process 1000 may be performed in various orders and / or simultaneously, and are not limited to the execution order shown in FIG. 10. The method for obtaining parameters of a mapping curve according to the present application includes the following steps.

[0118] Step 1001: Obtain a parameter set of a first mapping curve and a first maximum target system display luminance.

[0119] In the present application, the front end may be the front end in the video processing system shown in FIG. 8, and the back end may be the back end in the video processing system shown in FIG. 8. In this case, data from the front end may be transmitted to the back end by using a wireless network or a wired network. Alternatively, the front end and the back end may be integrated into the terminal device shown in FIG. 9. In this case, data from the front end may be transmitted to the back end by using an internal transmission path of the terminal device, for example, a Controller Area Network (CAN) bus. After receiving the data, the back end may store the data in a buffer for subsequent processing. The buffer may be, for example, an RGB color gamut pixel buffer of the frame to be processed and / or a metadata buffer of the frame to be processed.

[0120] After capturing the video, the front end may preprocess the video, for example, by using an optical-to-electrical transfer function to map real-world luminance to a luminance that matches the stored mode, adjust the brightness, chrominance, contrast, and the like of the video based on the captured information, and encode the video to generate a bitstream. The front end sends the processed data to the back end.

[0121] The data from the front end may include video data (also referred to as data of the content to be displayed) and dynamic metadata. The video data may be data related to image frames in the video, such as pixel data. The dynamic metadata may include data related to the video data and data related to the mapping curve. The data related to the video data may include a storable first maximum target system display luminance (targeted_system_display_maximum_luminance), a storable maximum luminance MaxSource, a storable minimum luminance MinSource, a storable average luminance AvgSource of the video in memory, or a storable variation range. The principle of the storable variation range is similar to that of a variance or distribution confidence interval, and the variation range is used to describe the luminance aggregate range of a video signal. The data related to the mapping curve may include parameters related to the mapping curve, such as scaling coefficients, offset coefficients, and bending shape coefficients. The parameter set of the first mapping curve includes one or more parameters in the data related to the mapping curve. For example, the data associated with the S-shaped curve includes eight parameters a, b, p, n, m, k1, k2, and k3, and the parameter set of the first mapping curve may include all eight parameters or only some of the eight parameters, where each of the some of the parameters is a rational number.

[0122] Optionally, data related to the video data may alternatively be extracted directly from the video content without being transmitted based on dynamic metadata.

[0123] The parameter set of the first mapping curve corresponds to a first maximum target system display luminance, i.e., one or more parameters in the parameter set of the first mapping curve are generated by using the first maximum target system display luminance as a target or are related to the first maximum target system display luminance. The front end may include the parameter set of the first mapping curve and the first maximum target system display luminance in the dynamic metadata. Alternatively, only the parameter set of the first mapping curve may be retained in the dynamic metadata, in which case the parameter set of the first mapping curve corresponds to a default maximum target system display luminance, and the front end and the back end have previously agreed on the default maximum target system display luminance. In this way, after receiving the parameter set of the first mapping curve, the back end may know the first maximum target system display luminance by default, provided that the front end includes the dynamic metadata in the parameter set of the first mapping curve corresponding to the dynamic metadata. When the backend needs to adjust the peak target system display luminance based on the actual situation, one or more parameters in the parameter set of the first mapping curve can be adjusted based on the relationship between the actual luminance and the default peak target system display luminance to obtain a parameter set of a new mapping curve corresponding to the actual luminance.

[0124] It should be noted that the content and data format included in the video data in this application are not specifically limited. For example, in terms of the color space of pixel data, the format of the video data may be YUV or RGB. In terms of data bit width, the video data may include 8 bits, 10 bits, 12 bits, or the like. The content included in the dynamic metadata is not specifically limited. For example, data related to a mapping curve may be parameters related to the aforementioned S-shaped curve, parameters related to the aforementioned Bezier curve, or parameters related to an S-shaped curve.

[0125] Step 1002: Obtain a display brightness parameter set.

[0126] In the present application, a display brightness parameter set may be obtained based on device information. The display brightness parameter set includes a maximum display brightness (MaxDisplay) and / or a minimum display brightness (MinDisplay) of a display device. The device information may be device parameters written to the device before shipping, or may be information provided by a manufacturer. The device information indicates the attributes and capabilities of the device.

[0127] Maximum display luminance refers to the maximum illuminance that can be presented by a device during display. Minimum display luminance refers to the minimum illuminance that can be presented by a device during display. Minimum display luminance is usually 0 cd / m 2 or 1 cd / m 2 The minimum display luminance may alternatively be set to another value based on the display performance of the device, which is not specifically limited in this application.

[0128] Step 1003: Obtain a set of adjustment coefficients.

[0129] The adjustment factor set includes information indicating that one or more parameters associated with the mapping curve need to be adjusted.

[0130] The adjustment coefficient set includes one or more adjustment coefficients, and the one or more adjustment coefficients correspond to one or more parameters in the parameter set of the first mapping curve. As described above, the parameter set of the first mapping curve includes one or more parameters associated with the mapping curve, and one adjustment coefficient in the adjustment coefficient set may correspond to one parameter in the parameter set of the first mapping curve, i.e., each parameter associated with the mapping curve corresponds to one adjustment coefficient. In addition, one adjustment coefficient in the adjustment coefficient set may alternatively correspond to multiple parameters in the parameter set of the first mapping curve, i.e., each adjustment coefficient corresponds to multiple parameters associated with the mapping curve. Alternatively, the adjustment coefficient set may not include an adjustment coefficient corresponding to one or more parameters in the parameter set of the first mapping curve, i.e., one or more parameters associated with the mapping curve in the parameter set of the first mapping curve do not correspond to any adjustment coefficient in the adjustment coefficient set. In this case, it indicates that the parameters do not need to be adjusted. Alternatively, the parameter set of the first mapping curve may include parameters that do not correspond to any adjustment coefficients in the adjustment coefficient set, i.e., one or more adjustment coefficients do not correspond to any parameters in the parameter set of the first mapping curve. In this case, it indicates that the front end does not currently send the parameters to the back end, but that the parameters need to be adjusted. The back end may obtain the parameters by using other methods.

[0131] In the present application, the device may obtain the adjustment coefficient set from the dynamic metadata. Before transmitting the bitstream, the front end may set a manner of adjusting one or more parameters related to the mapping curve, write the adjustment manner into the dynamic metadata, and send the dynamic metadata to the back end. Alternatively, the device may obtain the adjustment coefficient set based on a preset value. The preset value may correspond to one or more parameters related to the mapping curve, or may be an adjustment mode index. Based on the index, the device obtains adjustment coefficients corresponding to the preset values ​​of one or more parameters related to the mapping curve.

[0132] Step 1004: Adjust one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the adjustment coefficient set to obtain a parameter set of a second mapping curve.

[0133] The parameter set of the second mapping curve includes one or more adjusted parameters, which correspond to one or more parameters in the parameter set of the first mapping curve and are obtained by adjusting one or more parameters in the parameter set of the first mapping curve. It should be noted that the parameters included in the parameter set of the second mapping curve may correspond one-to-one to the parameters included in the parameter set of the first mapping curve. That is, each parameter included in the parameter set of the first mapping curve is added to the parameter set of the second mapping curve after being adjusted. This is applicable to the case where the parameter set of the first mapping curve includes all parameters related to the mapping curve. Alternatively, the parameters included in the parameter set of the second mapping curve may be parameters not included in the parameter set of the first mapping curve. That is, each parameter included in the parameter set of the first mapping curve is added to the parameter set of the second mapping curve after being adjusted, and some other parameters are obtained by the device using other methods, and then these some parameters are added to the parameter set of the second mapping curve after being adjusted or without being adjusted. This is applicable to the case where the parameter set of the first mapping curve includes some parameters related to the mapping curve, and the data included in the parameter set of the second mapping curve may alternatively be a set of adjusted parameters of the first mapping curve and unadjusted parameters of the first mapping curve.

[0134] In the following, the first parameter is used as an example to describe the method for obtaining the parameter set of the second mapping curve in this application, where the first parameter is any parameter in the parameter set of the first mapping curve.

[0135] Method 1: Calculate the adjusted first parameter according to equation (1). P a =P b +k×PΔ (1) where P a represents the adjusted first parameter, and P b represents the first parameter, and P Δ represents an adjustment coefficient corresponding to the first parameter,

number

number

[0136] The MaxDisplay value in this application is an absolute luminance value, for example, 100 cd / m 2 or 1000 cd / m 2 The value of MaxDisplay may be a normalized luminance value, whose value range is 0-1, and the value of MaxDisplay may be a luminance value in the PQ domain, for example, 0-10000 cd / m 2 It should be noted that in this application, M TPLThe value is the absolute luminance value, e.g., 100 cd / m 2 or 1000 cd / m 2 M TPL The values ​​of may be normalized luminance values, and M TPL The value range of is 0-1, and M TPL The value of is the luminance value in the PQ domain, e.g., 0-10000cd / m 2 In this application, the value of M may be an absolute luminance value, e.g., 100 cd / m 2 or 1000 cd / m 2 and the value of M may be a normalized luminance value, the value of M being in the range of 0-1, and the value of M being a luminance value in the PQ domain, e.g., 0-10000 cd / m 2 This is also true for the following method, and the details will not be described again.

[0137] All or some of the parameters in the parameter set of the first mapping curve may be adjusted according to the above equation (1) to obtain adjusted parameters added to the parameter set of the second mapping curve.

[0138] Method 2: Calculate the adjusted first parameter according to equation (2). P a =(1-w)×P b +w×P m (2) where: P a represents the adjusted first parameter, and P b represents the first parameter,

number

number

[0139] P m It should be noted that P may be obtained based on more or fewer parameters than the above-mentioned maximum display brightness, minimum display brightness, memorizable maximum brightness, memorizable minimum brightness, memorizable average value, and / or memorizable variation range. This is not specifically limited in this application. This is also true for the following methods, and the details will not be described again. In this application, P m To obtain the above, we refer to the method of generating a mapping curve in the related art, which is not specifically limited in this application.

[0140] It should be noted that in Method 2, the device may obtain another parameter set related to the mapping curve based on data related to the video data, such as the maximum, minimum, average, and / or variation range of the video that can be stored in memory, the device's maximum display brightness, the device's minimum display brightness, and / or other parameters not directly related to the mapping curve. The parameters in the parameter set may correspond one-to-one to the parameters in the parameter set of the first mapping curve, or the parameter set may include parameters not present in the parameter set of the first mapping curve. In this way, the device may obtain two parameter sets related to the mapping curve. One of the sets may originate from the front end, and the other set may be obtained by the device through calculations based on the characteristics of the video data. The two parameter sets are then fused using a weighting method to obtain a final parameter set. In this way, a more flexible brightness processing method may be used at different positions of the video by adjusting the weights of the two parameter sets to obtain a video that better meets the display performance of the device.

[0141] In addition, P m The method for calculating (a) can be further applied to parameters related to the mapping curve but not included in the parameter set of the first mapping curve. The manner in which the above-mentioned device obtains parameters by using other methods is similar to this method.

[0142] In a possible implementation, the device may obtain a first mapping curve based on the adjusted first parameter and parameters in the parameter set of the first mapping curve other than the first parameter, and may continue adjusting the first parameter if the luminance of the video obtained by performing tone mapping based on the first mapping curve is higher than the original luminance of the video, thereby ensuring that the mapping curve does not include a portion higher than the straight line satisfying x=y.

[0143] In a possible implementation, the adjusted first parameter is analyzed according to a preset rule, and if the adjusted first parameter meets the preset rule, the adjustment of the first parameter continues. For example, p a ×r a >Tp a where p a is the first parameter, and r a is a scaling factor, and Tp a is a certain threshold, for example, 3.2363. In this case, p a is adjusted to the upper limit Tp, where Tp = Tp a / r a Alternatively, r a A pre-defined table (Ta, Tp) can be searched for Tp corresponding to p a >If Tp, then p a is adjusted to the upper limit value Tp. It should be noted that if the same value cannot be found by table lookup, the queried value may be determined based on a nearby value or a weighted average of nearby values, or in other manners. The above two inequalities indicate that the mapping curve obtained based on the current parameter set associated with the mapping curve includes a portion higher than the straight line satisfying x=y. Therefore, a dimension reduction process needs to be performed on the corresponding parameters. It should be noted that in addition to the above two methods, other methods may be used in the present application to ensure that the mapping curve does not include a portion higher than the straight line satisfying x=y. This is not particularly limited.

[0144] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, the adjusted scaling factor is calculated according to equation (3).

number

[0145] If a scaling factor is included in the acquisition of the mapping curve, the device may calculate the scaling factor based on the acquired one or more adjusted parameters in the parameter set of the second mapping curve and according to equation (3). In this way, the scaling factor is acquired based on the adjusted parameters, and therefore the finally generated mapping curve better meets the characteristics of the video. The scaling factor determines the degree of scaling of the linear signal value of the pixel of the image frame in the equation of the mapping curve. For example, in the following equation, a is the scaling factor:

number

[0146] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, the adjusted scaling factor is calculated according to equation (4).

number

[0147] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, the adjusted scaling factor is calculated according to equation (5).

number

[0148] In a possible implementation, when the parameter set of the first mapping curve includes a scaling factor, the adjusted scaling factor is calculated according to equation (6).

number

[0149] In a possible implementation, when the parameter set of the first mapping curve includes an offset coefficient, the adjusted offset coefficient is determined in the following manner: r a =MinDisplay, where MinDisplay represents the minimum display luminance, or r a =G, where G represents a preset value and can be a rational number, for example, 0 or 1.

[0150] If a scaling factor is included in the acquisition of the mapping curve, the device may calculate the scaling factor based on any one of the acquired one or more adjusted parameters in the parameter set of the second mapping curve and according to the above formula. In this way, the scaling factor is acquired based on the adjusted parameters, and therefore the finally generated mapping curve better meets the characteristics of the video.

[0151] Step 1005: Obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0152] Based on one or more adjusted parameters, a whole mapping curve or a part of a tone mapping curve can be obtained. The calculation of the curve is to obtain a mapping from normalized HDR / SDR data to normalized display data, and then inversely normalize the obtained mapping value to the data actually displayed on the device based on the maximum display luminance and minimum display luminance of the device.

[0153] It should be noted that the aforementioned inverse normalization may be in a non-linear space or may be a normalization to 0-1 in a linear space. 2 May be 0.001-100000cd / m 2 The range and process of denormalization may be not specifically limited in this application. In addition, obtaining the mapping curve not only includes performing tone mapping, but also includes adjusting the mapped video to adjust saturation processing, color gamut conversion processing, noise reduction processing, sharpening processing, and / or the like of the mapped video before the mapped video is displayed, which is not specifically limited in this application.

[0154] In this application, one or more parameters related to the mapping curve are adjusted. In the adjustment process, the display capabilities of the backend are taken into account, so that more accurate tone adjustment can be performed on display devices with different brightness levels. This greatly improves flexibility and also achieves good presentation effects when the curve parameters are set appropriately.

[0155] The following will further illustrate the solution of the embodiment of the method in FIG. 10 by using some specific embodiments. [Embodiment 1]

[0156] For an S-curve, the dynamic metadata may include statistics of the video in memory, such as the maximum luminance that can be stored, the minimum luminance that can be stored, and the average luminance that can be stored, and may include parameters related to the S-curve, such as p, m, a, b, n, K1, K2, and K3.

[0157] 1: Obtain a first mapping curve parameter set and a first maximum target system display luminance.

[0158] Dynamic metadata is Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b}, the parameter set of the first mapping curve that satisfies the maximum target system display luminance (targeted_system_display_maximum_luminance) M TPL , and / or the format or characteristics of the video data such as the maximum storable brightness MaxSource, the minimum storable brightness MinSource, the average storable brightness AvgSource, and / or the storable variation range of the video in the memory.

[0159] It should be noted that the content and data format of the video data are not specifically limited in this application. For example, in terms of the color space of pixel data, the format of the video data may be YUV or RGB. In terms of data bit width, the video data may include 8 bits, 10 bits, 12 bits, or the like.

[0160] 2: Get the backend display parameter set.

[0161] The display parameter set includes the backend maximum display luminance (MaxDisplay), minimum display luminance (MinDisplay), and / or maximum targeted system display luminance (targeted_system_display_maximum_luminance) T TPL The maximum display luminance, MaxDisplay, may be obtained based on device parameters or information about the manufacturer, and the minimum display luminance, MinDisplay, may be 0 cd / m 2 , 1cd / m 2 , or 0 cd / m 2 or 1 cd / m 2 The minimum display luminance may be set to a PQ value corresponding to the minimum display luminance of the device. Alternatively, the minimum display luminance may be set to another value based on the display performance of the device, which is not specifically limited in this application.

[0162] 3: Obtain the adjustment factor set.

[0163] Corresponding to the parameter set Mb of the first mapping curve, the adjustment coefficient set M Δ is {p Δ ,m Δ ,a Δ ,b Δ ,n Δ ,K1 Δ ,K2 Δ , and K3 Δ}. Generally, the adjustment factor set may be obtained based on metadata or may be preset.

[0164] 4: Adjust one or more parameters in the parameter set of the first mapping curve based on the local maximum display luminance, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of the second mapping curve.

[0165] Ma={p a ,m a ,a a ,b a ,n a ,K1 a ,K2 a ,K3 a}, Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b One or more parameters in the parameter set of the first mapping curve that satisfies} are adjusted. The main steps are as follows:

[0166] A:Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b The parameter set of the first mapping curve that satisfies b (Q b is an arbitrary parameter in Mb). Δ is the corresponding adjustment coefficient Q Δ If it contains, Q a =Q b +k×Q Δ otherwise, Q a =Q b is.

number

number

[0167] B:b a =MinDisplay or b a Set =0.

[0168] C:a a is set by the following formula:

number

[0169] D: If the mapping curve obtained based on the current parameter set of the second mapping curve includes a portion higher than the straight line satisfying x=y, p a The main methods are as follows:

[0170] p a ×a a >Tp a It is considered that the mapping curve includes a part higher than the straight line satisfying x=y when Tp a is a preset value, and Tp = Tp a / a a or a a A pre-set table (Ta, Tp) is searched for Tp corresponding to p a >Tp, then p ais adjusted to an upper limit value Tp. It should be noted that if the same value cannot be found by table lookup, the queried value may be determined based on a nearby value or a weighted average of nearby values, or in other manners.

[0171] In this case, the scaling factor a a is calculated according to the following formula:

number

number

number

[0172] L=MaxSource and L1=MinSource.

[0173] a a The calculation of is also true for the following method, and the details will not be explained again.

[0174] 5: Obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve. The process of obtaining a mapping curve is essentially a process of obtaining a normalized optical or electrical signal based on the parameter set.

[0175] For a function calculation related to one or more adjusted parameters in the parameter set of the second mapping curve, obtained based on one or more adjusted parameters in the parameter set of the second mapping curve, the mapping curve can be obtained according to the following formula:

number

number

number

number

[0176] The parameters {p, m, a, b, n, K1, K2, and K3} in the formula all come from the parameter set of the second mapping curve. L and L' are each normalized electrical or optical signals, L' is a rational number having a value range of 0.0-1.0, L is a rational number having a value range of 0.0-1.0, a value range is 0.0-1.0, b value range is 0.0-1.0, p, n, and m value range is 0.1-N, N is a rational number greater than 0.1, and K1, K2, and K3 are rational numbers. The calculation of L' is also true for the following method, and the details will not be described again.

[0177] It should be noted that all of the above four equations can be used to obtain a mapping curve, but the differences lie in one or more adjusted parameters related to the mapping curve and in the parameter set of the second mapping curve. The mapping curve obtained according to the equations may be the entire curve, or a segment or part of the segmented mapping curve. [Embodiment 2]

[0178] For an S-curve, the dynamic metadata may include statistics of the video in memory, such as the maximum luminance that can be stored, the minimum luminance that can be stored, the average luminance that can be stored, and the variation range that can be stored, and may include parameters related to the S-curve, such as p, m, a, b, n, K1, K2, and K3.

[0179] 1: Obtain a first mapping curve parameter set and a first maximum target system display luminance.

[0180] 2: Get the backend display parameter set.

[0181] 3: Obtain the adjustment factor set.

[0182] The technical principles of Steps 1 to 3 in Embodiment 2 are similar to those of Steps 1 to 3 in Embodiment 1, respectively, and the details will not be described again in this specification.

[0183] 4: Adjust one or more parameters in the parameter set of the first mapping curve based on the local maximum display luminance, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of the second mapping curve.

[0184] Ma={p a ,m a ,a a ,b a ,n a ,K1 a ,K2 a ,K3 a}, Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b One or more parameters in the parameter set of the first mapping curve that satisfies} are adjusted. The main steps are as follows:

[0185] A: Mm={p m ,m m ,a m ,b m ,n m ,K1 m ,K2 m ,K3 m} and obtain another set of parameters related to the mapping curve, where one or more parameters in Mm are the parameters P in the above equation (2). m It can be used as.

[0186] B:Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b The parameter set of the first mapping curve that satisfies b (Q b is an arbitrary parameter in Mb). m Mm={p m ,m m ,a m ,b m ,n m ,K1 m ,K2 m ,K3 m}, Q a =(1-w)×Q b +w×Q m otherwise, Q a =Q b is.

number

number

[0187] C:b a =MinDisplay or ba Set =0.

[0188] D: Scaling coefficient a a For the calculation formula, please refer to embodiment 1. The details will not be described again in this specification.

[0189] 5: Obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0190] The technical principle of step 5 in embodiment 2 is similar to that of step 5 in embodiment 1, and the details will not be described again in this specification. [Embodiment 3]

[0191] For an S-curve, the dynamic metadata may include statistics of the video in memory, such as the maximum luminance that can be stored, the minimum luminance that can be stored, the average luminance that can be stored, and the variation range that can be stored, and may include parameters related to the S-curve, such as p, m, a, b, n, K1, K2, and K3.

[0192] 1: Obtain a first mapping curve parameter set and a first maximum target system display luminance.

[0193] 2: Get the backend display parameter set.

[0194] 3: Obtain the adjustment factor set.

[0195] The technical principles of Steps 1 to 3 in Embodiment 3 are similar to those of Steps 1 to 3 in Embodiment 1, respectively, and the details will not be described again in this specification.

[0196] 4: Adjust one or more parameters in the parameter set of the first mapping curve based on the local maximum display luminance, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of the second mapping curve.

[0197] Ma={p a ,m a ,a a ,b a ,n a ,K1 a ,K2 a ,K3 a}, Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b One or more parameters in the parameter set of the first mapping curve that satisfies} are adjusted. The main steps are as follows:

[0198] A: Mm={p m ,m m ,a m ,b m ,n m ,K1 m ,K2 m ,K3 m} and obtain another set of parameters related to the mapping curve, where one or more parameters in Mm are the parameters P in the above equation (2). m It can be used as.

[0199] B:Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b The parameter set of the first mapping curve that satisfies b (Q bis an arbitrary parameter in Mb). m Mm={p m ,m m ,a m ,b m ,n m ,K1 m ,K2 m ,K3 m}, Q a =(1-w)×Q b +w×Q m otherwise, Q a =Q b is.

number

number

[0200] C:b a =MinDisplay or b a Set =0.

[0201] D:a a is set by the following formula:

number

[0202] E: If the mapping curve obtained based on the current parameter set of the second mapping curve includes a part higher than the straight line satisfying x=y, p aThe main methods are as follows:

[0203] p a ×a a >Tp a It is considered that the mapping curve includes a part higher than the straight line satisfying x=y when Tp a is a preset value, and Tp = Tp a / a a or a a A pre-set table (Ta, Tp) is searched for Tp corresponding to p a >Tp, then p a is adjusted to an upper limit value Tp. It should be noted that if the same value cannot be found by table lookup, the queried value may be determined based on a nearby value or a weighted average of nearby values, or in other manners.

[0204] Scaling factor a a For the calculation formula, please refer to embodiment 1. The details will not be described again in this specification.

[0205] 5: Obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0206] The technical principle of step 5 in embodiment 3 is similar to that of step 5 in embodiment 1, and the details will not be described again in this specification. [Embodiment 4]

[0207] For an S-curve, the dynamic metadata may include statistics of the video in memory, such as the maximum luminance that can be stored, the minimum luminance that can be stored, and the average luminance that can be stored, and may include parameters related to the S-curve, such as p, m, a, b, n, K1, K2, and K3.

[0208] 1: Obtain a first mapping curve parameter set and a first maximum target system display luminance.

[0209] 2: Get the backend display parameter set.

[0210] 3: Obtain the adjustment factor set.

[0211] The technical principles of Steps 1 to 3 in Embodiment 4 are similar to those of Steps 1 to 3 in Embodiment 1, respectively, and the details will not be described again in this specification.

[0212] 4: Adjust one or more parameters in the parameter set of the first mapping curve based on the local maximum display luminance, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of the second mapping curve.

[0213] Ma={p a ,m a ,a a ,b a ,n a ,K1 a ,K2 a ,K3 a}, Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b One or more parameters in the parameter set of the first mapping curve that satisfies} are adjusted. The main steps are as follows:

[0214] A:Mb={p b ,m b ,a b ,b b ,n b ,K1 b ,K2 b ,K3 b The parameter set of the first mapping curve that satisfies b (Q b is an arbitrary parameter in Mb). Δis the corresponding adjustment coefficient Q Δ If it contains, Q a =Q b +k×Q Δ otherwise, Q a =Q b is.

number

number

[0215] B:b a =MinDisplay or b a Set =0.

[0216] Scaling factor a a For the calculation formula, please refer to embodiment 1. The details will not be described again in this specification.

[0217] 5: Obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0218] The technical principle of Step 5 in Embodiment 4 is similar to that of Step 5 in Embodiment 1, and the details will not be described again in this specification. [Embodiment 5]

[0219] This embodiment is used to describe a pre-operational stage of the process of acquiring a basic HDR curve (parameters) in any one of the first to fourth embodiments, and specifically includes the following stages.

[0220] 1: Obtain the base curve parameter Stone_mapping from the dynamic metadata (metadata) information.

[0221] m_p, m_a, m_m, m_n, m_b, K1, K2, and K3 are obtained based on the tone mapping identifier tone_mapping_mode and the base curve identifier base_flag in the metadata information, and non-existent parameters are set to the assigned value N_A.

[0222] 2: The maximum correction luminance value max_lum of the frame to be processed and the minimum luminance value min_lum of the frame to be processed are obtained from the metadata information.

[0223] The maximum correction luminance value max_lum of the frame to be processed is updated.

[0224] 3:P tone_mapping To obtain the base curve parameter S tone_mapping Update parameters that have unassigned values ​​in .

[0225] A:When tone_mapping_mode is 0, the following base curve parameters are called to get the processing update parameters:

[0226] The input is the maximum display luminance (MaxDisplay) in the display luminance range of the display device (value in the PQ domain), the minimum display luminance (MinDisplay) in the display luminance range of the display device (value in the PQ domain), and metadata information. The output is the base curve parameters P, including m_p, m_a, m_m, m_n, m_b, K1, K2, and K3. tone_mapping is.

[0227] (1) Set m_m, m_n, K1, K2, and K3 to preset values ​​2.4, 1, 1, 1, and 1, respectively. After the above parameters are preset, the following curve is obtained:

number

[0228] (2) Set m_b to MinDisplay.

[0229] (3) Calculate m_p based on average_maxrgb(avgL) in the metadata information.

number

[0230]

number

[0231] (4) Update m_p based on the maximum corrected luminance value max_lum.

number

[0232]

number

[0233] (5) Based on m_p, m_m, m_n, m_b, K1, K2, and K3, H(L)

number

number

[0234] MaxSource represents the maximum corrected luminance value max_lum (in the PQ domain) of the frame to be processed, and MinSource represents the minimum luminance value min_lum (in the PQ domain) of the frame to be processed.

[0235] B: When tone_mapping_mode is 1, if the maximum target system display luminance targeted_system_display_maximum_luminance is equal to MaxDisplay, set m_p, m_a, m_m, m_n, m_b, K1, K2, and K3 to m_p_0, m_a_0, m_m_0, m_n_0, m_b_0, K1_0, K2_0, and K3_0; otherwise, adjust the base curve parameters by using any one of the solutions from embodiment 1 to embodiment 4.

[0236] When entering the aforementioned branch B, i.e., when tone_mapping_mode is 1, it should be noted that the decision process of "when the maximum target system display luminance targeted_system_display_maximum_luminance is equal to MaxDisplay, set m_p, m_a, m_m, m_n, m_b, K1, K2, and K3 to m_p_0, m_a_0, m_m_0, m_n_0, m_b_0, K1_0, K2_0, and K3_0" is an optional step, and the base curve parameters can be directly adjusted by using any one of the solutions from embodiment 1 to embodiment 4, and the output results will be consistent. Performing a decision process such as "if the maximum target system display luminance targeted_system_display_maximum_luminance is equal to MaxDisplay, then set m_p, m_a, m_m, m_n, m_b, K1, K2, and K3 to m_p_0, m_a_0, m_m_0, m_n_0, m_b_0, K1_0, K2_0, and K3_0" may reduce the complexity and calculation time in an actual hardware implementation process.

[0237] For example, the implementation of embodiment 1 may be as follows:

[0238] The inputs are the maximum display luminance (MaxDisplay) in the display luminance range of the display device (value in the PQ domain), the minimum display luminance (MinDisplay) in the display luminance range of the display device (value in the PQ domain), the RGB color gamut pixel buffer f[Nframe][3] of the frame to be processed, and m_p_0, m_a_0, m_m_0, m_n_0, m_b_0, K1_0, K2_0, K3_0, targeted_system_display_maximum_luminance(M TPL ), and metadata information including base_param_Delta. The output is the base curve parameters P including m_p, m_a, m_m, m_n, m_b, K1, K2, and K3. tone_mapping is.

[0239] (1) Set m_m, m_n, K1, K2, and K3 to m_m_0, m_n_0, K1_0, K2_0, and K3_0, respectively.

[0240] (2) Set m_b to MinDisplay.

[0241] (3) Set m_a as follows:

number

[0242] (4) Set m_p as follows:

number

[0243] (5) Obtain the following equation:

number

[0244] (6) Substitute L=MaxSource into the following formula to obtain m_a.

number

[0245] For example, the implementation of embodiment 2 can be as follows:

[0246] The inputs are the maximum display luminance (MaxDisplay) in the display luminance range of the display device (value in the PQ domain), the minimum display luminance (MinDisplay) in the display luminance range of the display device (value in the PQ domain), average_maxrgb in the metadata, the RGB color gamut pixel buffer f[Nframe][3] of the frame to be processed, and m_p_0, m_m_0, m_n_0, m_a_0, m_b_0, K1_0, K2_0, K3_0, targeted_system_display_maximum_luminance(M TPL ), and metadata information including base_param_Delta. The output is the base curve parameters P including m_p, m_m, m_n, m_a, m_b, K1, K2, and K3. tone_mapping is.

[0247] (1) Base curve parameters P1 including m_p_1, m_m_1, m_n_1, m_a_1, m_b_1, K1_1, K2_1, and K3_1 tone_mapping Generate.

[0248] (2) Calculate w according to the following formula:

number

[0249] (3) Calculate m_p, m_m, m_n, K1, K2, and K3 according to m_p=(1-w)×m_p_0+w×m_p_1, m_m=(1-w)×m_m_0+w×m_m_1, m_n=(1-w)×m_n_0+w×m_n_1, K1=(1-w)×K1_0+w×K1_1, K2=(1-w)×K2_0+w×K2_1, and K3=(1-w)×K3_0+w×K3_1.

[0250] (4) Set m_b to MinDisplay.

[0251] (5) Obtain the following equation:

number

[0252] (6) Substitute L=MaxSource into the following formula to obtain m_a.

number

[0253] Based on the same inventive idea as the above-mentioned method, an embodiment of the present application further provides a video processing device. Fig. 11 is a structural block diagram of a video processing device 1100 configured to implement an embodiment of the present application. As shown in Fig. 11, the video processing device 1100 includes an acquisition module 1101 and a processing module 1102. The acquisition module 1101 is configured to: acquire a parameter set of a first mapping curve and a first maximum target system display luminance, where the parameter set of the first mapping curve corresponds to a first maximum target system display luminance, and the parameter set of the first mapping curve includes one or more parameters related to the mapping curve; acquire a display luminance parameter set, where the display luminance parameter set includes a maximum display luminance and / or a minimum display luminance of a display device; and acquire an adjustment coefficient set, where the adjustment coefficient set includes one or more adjustment coefficients, and the one or more adjustment coefficients correspond to one or more parameters in the parameter set of the first mapping curve. The processing module 1102 is configured to adjust one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of a second mapping curve, wherein the parameter set of the second mapping curve includes the one or more adjusted parameters.

[0254] In a possible implementation, the processing module 1102 specifically: P a =P b +k×P Δ (1) and calculating an adjusted first parameter according to Equation (1), where the first parameter is any parameter in the parameter set of the first mapping curve; and a represents the adjusted first parameter, and P b represents the first parameter, and P Δ represents an adjustment coefficient corresponding to the first parameter,

number

number

[0255] In a possible implementation, the acquisition module 1101 is further configured to: acquire one or more of a storable maximum brightness, a storable minimum brightness, a storable average value, and a storable variation range; and acquire an intermediate value of a first parameter based on one or more of a maximum display brightness, a minimum display brightness, a storable maximum brightness, a storable minimum brightness, a storable average value, and a storable variation range, where the first parameter is any parameter in the parameter set of the first mapping curve. P a =(1-w)×P b +w×P m (2) and calculating the adjusted first parameter according to equation (2), arepresents the adjusted first parameter, and P b represents the first parameter,

number

number

[0256] In a possible implementation, the processing module 1102 is further configured to obtain a first mapping curve based on the adjusted first parameter and parameters in the parameter set of the first mapping curve other than the first parameter, and continue adjusting the first parameter if the luminance of the video obtained by performing tone mapping based on the first mapping curve is higher than the original luminance of the video, or analyze the adjusted first parameter according to a predetermined rule, and continue adjusting the first parameter if the adjusted first parameter complies with the predetermined rule.

[0257] In a possible implementation, the processing module 1102 specifically performs the following when the parameter set of the first mapping curve includes a scaling factor:

number

[0258] In a possible implementation, the processing module 1102 specifically performs the following when the parameter set of the first mapping curve includes a scaling factor:

number

[0259] In a possible implementation, the processing module 1102 specifically performs the following when the parameter set of the first mapping curve includes a scaling factor:

number

[0260] In a possible implementation, the processing module 1102 specifically performs the following when the parameter set of the first mapping curve includes a scaling factor:

number

[0261] In a possible implementation, the acquisition module 1101 is specifically configured to acquire a parameter set of a first mapping curve and a first maximum target system display luminance from the dynamic metadata of the video, or to acquire a parameter set of a first mapping curve from the dynamic metadata and acquire a first maximum target system display luminance corresponding to the parameter set of the first mapping curve based on a specific correspondence.

[0262] In a possible implementation, the acquisition module 1101 is specifically configured to acquire the set of adjustment coefficients from dynamic metadata of the video, or to acquire the set of adjustment coefficients based on a preset value.

[0263] In a possible implementation, the acquisition module 1101 is specifically configured to directly read one or more adjustment factors, or to acquire an adjustment mode and acquire one or more adjustment factors corresponding to the adjustment mode.

[0264] In a possible implementation, the acquisition module 1101 is specifically configured to acquire a display brightness parameter set based on device information, or to acquire a display brightness parameter set based on preset information.

[0265] In a possible implementation, the obtaining module 1101 is further configured to obtain a mapping curve based on one or more adjusted parameters in the parameter set of the second mapping curve.

[0266] It should be further noted that the specific implementation processes of the acquisition module 1101 and the processing module 1102 refer to the detailed description in the embodiment of Figure 10. For the sake of conciseness, the details will not be described again in this specification.

[0267] Those skilled in the art will understand that the functionality described in connection with the various illustrative logical blocks, modules, and algorithm steps disclosed and described herein may be implemented by hardware, software, firmware, or any combination thereof. If implemented by software, the functionality described in connection with the illustrative logical blocks, modules, and steps may be stored on or transmitted via a computer-readable medium as one or more instructions or code and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media corresponding to tangible media, such as data storage media, and may also include any communication medium that facilitates the transfer of a computer program from one place to another (e.g., according to a communication protocol). As such, computer-readable media may generally correspond to (1) non-transitory tangible computer-readable storage media or (2) communication media, such as a signal or carrier. Data storage media may be any available medium from which one or more computers or one or more processors can access to obtain instructions, code, and / or data structures for implementing the techniques described herein. A computer program product may include a computer-readable medium.

[0268] By way of example, and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, flash memory, or any other medium that can store required program code in the form of instructions or data structures or that can be accessed by a computer. Additionally, any connection is appropriately referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source over coaxial cable, fiber optic, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio waves, or microwave, the coaxial cable, fiber optic, twisted pair, DSL, or wireless technologies such as infrared, radio waves, or microwave are included within the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carriers, signals, or other transitory media, and in fact refer to non-transitory tangible storage media. As used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), and Blu-ray discs. Disks typically replicate data magnetically, while discs replicate data optically by using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0269] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or equivalent integrated or discrete logic circuitry. Accordingly, the term "processor," as used herein, may refer to such structures or any other structure applicable to implementing the techniques described herein. Additionally, in some aspects, the functionality described in connection with the exemplary logic blocks, modules, and stages described herein may be provided in dedicated hardware and / or software modules configured for encoding and decoding, or may be incorporated into a combined codec. Additionally, the techniques may be implemented entirely within one or more circuits or logic elements.

[0270] The techniques of the present application may be implemented in a variety of apparatuses or devices, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Various components, modules, or units are described herein to emphasize functional aspects of devices configured to perform the disclosed techniques, but are not necessarily realized by different hardware units. Indeed, as noted above, the various units may be combined into encoder and decoder hardware units in combination with appropriate software and / or firmware, or may be provided by interoperable hardware units (including one or more processors as described above).

[0271] In the above-mentioned embodiments, the description of each embodiment has its own focus, and for the parts not described in detail in one embodiment, reference is made to the related descriptions in other embodiments.

[0272] The above description is merely an exemplary specific implementation of the present application and is not intended to limit the scope of protection of the present application. Any variations or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application shall fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims. [Other possible items] [Item 1] 1. A method for obtaining parameters of a mapping curve, comprising: obtaining a first mapping curve parameter set and a first maximum target system display luminance, the first mapping curve parameter set corresponding to the first maximum target system display luminance, the first mapping curve parameter set including one or more parameters associated with a mapping curve; obtaining a display luminance parameter set, the display luminance parameter set including a maximum display luminance and / or a minimum display luminance of a display device; obtaining an adjustment coefficient set, the adjustment coefficient set including one or more adjustment coefficients, the one or more adjustment coefficients corresponding to the one or more parameters in a parameter set of the first mapping curve; adjusting the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a second mapping curve parameter set, wherein the second mapping curve parameter set includes one or more adjusted parameters; A method comprising: [Item 2] adjusting the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a second mapping curve parameter set, P a =P b +k×P Δ (1) calculating an adjusted first parameter according to equation (1), wherein the first parameter is any parameter in a parameter set of the first mapping curve, and the adjusted first parameter belongs to a parameter set of the second mapping curve; and P a represents the adjusted first parameter, and P b represents the first parameter, and P Δ represents an adjustment coefficient corresponding to the first parameter,

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Claims

1. 1. A method for obtaining parameters of a mapping curve, comprising: obtaining a first mapping curve parameter set and a first maximum target system display luminance, the first mapping curve parameter set corresponding to the first maximum target system display luminance, the first mapping curve parameter set including one or more parameters associated with a mapping curve; obtaining a display luminance parameter set, the display luminance parameter set including a maximum display luminance and / or a minimum display luminance of a display device; obtaining a set of adjustment factors, the set of adjustment factors including one or more adjustment factors, the one or more adjustment factors corresponding to the one or more parameters in a parameter set of the first mapping curve; adjusting a first parameter of the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a second mapping curve parameter set, wherein the second mapping curve parameter set includes the adjusted first parameter; analyzing the adjusted first parameter according to a predetermined rule, and continuing to adjust the first parameter if the adjusted first parameter complies with the predetermined rule; A method comprising:

2. A method for obtaining parameters of a mapping curve, comprising: obtaining a first mapping curve parameter set and a first maximum target system display luminance, the first mapping curve parameter set corresponding to the first maximum target system display luminance, the first mapping curve parameter set including one or more parameters associated with a mapping curve; obtaining a display luminance parameter set, the display luminance parameter set including a maximum display luminance and / or a minimum display luminance of a display device; obtaining a set of adjustment factors, the set of adjustment factors including one or more adjustment factors, the one or more adjustment factors corresponding to the one or more parameters in a parameter set of the first mapping curve; adjusting a first parameter of the one or more parameters in the first mapping curve parameter set based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a second mapping curve parameter set, wherein the second mapping curve parameter set includes the adjusted first parameter; obtaining a first mapping curve based on the adjusted first parameter and parameters in the parameter set of the first mapping curve other than the first parameter; continuing to adjust the first parameter when a luminance of the content to be displayed obtained by performing tone mapping based on the first mapping curve is higher than an original luminance of the content to be displayed; A method comprising:

3. adjusting the first parameter of the one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of a second mapping curve, comprising: When the parameter set of the first mapping curve includes a scaling factor, [Equation 5] calculating the adjusted scaling factor according to equation (3) and r ａ represents the adjusted scaling factor, and P1 ａ , P2 ａ , ... represent parameters in the parameter set of the second mapping curve, MaxSource represents the maximum brightness of the content to be displayed in memory, and f(MaxSource, P1 ａ , P2 ａ 3. The method of claim 1 or 2, wherein MaxDisplay represents a function calculation relating the maximum brightness of the content to be displayed in the memory and one or more adjusted parameters in the parameter set of the second mapping curve, and MaxDisplay represents the maximum display brightness.

4. adjusting the first parameter of the one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of a second mapping curve, comprising: When the parameter set of the first mapping curve includes a scaling factor, [Equation 6] calculating the adjusted scaling factor according to equation (4) and r ａ represents the adjusted scaling factor, and P1 ａ , P2 ａ , ... represent parameters in the parameter set of the second mapping curve, MaxSource represents the maximum luminance of the content to be displayed in memory, MinSource represents the minimum luminance of the content to be displayed in memory, and f(MaxSource, P1 ａ , P2 ａ , ...) represents a function calculation relating the maximum luminance of the content to be displayed in the memory and one or more adjusted parameters in the parameter set of the second mapping curve, and f(MinSource, P1 ａ , P2 ａ 3. The method of claim 1 or 2, wherein MaxDisplay represents the maximum display luminance and MinDisplay represents the minimum display luminance, and wherein MaxDisplay, MinDisplay, ...) represent a function calculation relating the minimum luminance of the content to be displayed in the memory and one or more adjusted parameters in the parameter set of the second mapping curve.

5. adjusting the first parameter of the one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of a second mapping curve, comprising: When the parameter set of the first mapping curve includes a scaling factor, [Equation 7] calculating the adjusted scaling factor according to equation (5) and r ａ represents the adjusted scaling factor, and P1 ａ , P2 ａ , ... represent parameters in the parameter set of the second mapping curve, MaxSource represents the maximum brightness of the content to be displayed in memory, and f(MaxSource, P1 ａ , P2 ａ 3. The method of claim 1 or 2, wherein MaxDisplay represents the maximum display luminance and MinDisplay represents the minimum display luminance, and wherein MaxDisplay, MinDisplay, ...) represent a function calculation relating the maximum luminance of the content to be displayed in the memory and one or more adjusted parameters in the parameter set of the second mapping curve.

6. adjusting the first parameter of the one or more parameters in the parameter set of the first mapping curve based on the display luminance parameter set, the first maximum target system display luminance, and the set of adjustment coefficients to obtain a parameter set of a second mapping curve, comprising: When the parameter set of the first mapping curve includes a scaling factor, [Equation 8] calculating the adjusted scaling factor according to equation (6) and r ａ represents the adjusted scaling factor, and P1 ａ , P2 ａ , ... represent parameters in the parameter set of the second mapping curve, MaxSource represents the maximum luminance of the content to be displayed in memory, MinSource represents the minimum luminance of the content to be displayed in memory, and f(MaxSource, P1 ａ , P2 ａ , ...) represents a function calculation relating the maximum luminance of the content to be displayed in the memory and one or more adjusted parameters in the parameter set of the second mapping curve, and f(MinSource, P1 ａ , P2 ａ 3. The method of claim 1 or 2, wherein ∑maxDisplay, ...

7. Prior to the step of adjusting the first parameter, the method further comprises: acquiring one or more of a maximum luminance, a minimum luminance, an average luminance, and a fluctuation range of the content to be displayed; obtaining an intermediate value of the first parameter based on one or more of the maximum display luminance, the minimum display luminance, the maximum luminance, the minimum luminance, the average value, and the variation range; 7. The method of claim 1, further comprising:

8. 1. A video processing device comprising: at least one processor; one or more memories coupled to said at least one processor and storing programming instructions for execution by said at least one processor to cause said video processing device to perform the method of any one of claims 1 to 7; A video processing device comprising:

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