| Name |
| |
| EXT_surface_SMPTE2086_metadata |
| |
| Name Strings |
| |
| EGL_EXT_surface_SMPTE2086_metadata |
| |
| Contact |
| |
| Weiwan Liu (weiwliu 'at' nvidia.com) |
| |
| Contributors |
| |
| Tom Cooksey |
| Courtney Goeltzenleuchter |
| Mathias Heyer |
| Lauri Hyvarinen |
| James Jones |
| Daniel Koch |
| Jeff Leger |
| Sandeep Shinde |
| |
| IP Status |
| |
| No known IP claims. |
| |
| Status |
| |
| Complete |
| |
| Version |
| |
| Version 8 - Oct 16, 2017 |
| |
| Number |
| |
| EGL Extension #109 |
| |
| Dependencies |
| |
| This extension requires EGL 1.4. |
| |
| This extension is written against the wording of the EGL 1.5 specification |
| (August 27, 2014). |
| |
| Overview |
| |
| This extension adds a new set of EGL surface attributes for the metadata |
| defined by the SMPTE (the Society of Motion Picture and Television |
| Engineers) ST 2086 standard. The SMPTE 2086 metadata includes the color |
| primaries, white point and luminance range of the mastering display, which |
| all together define the color volume that contains all the possible colors |
| the mastering display can produce. The mastering display is the display |
| where creative work is done and creative intent is established. To preserve |
| such creative intent as much as possible and achieve consistent color |
| reproduction on different viewing displays, it is useful for the display |
| pipeline to know the color volume of the original mastering display where |
| content is created or tuned. This avoids performing unnecessary mapping of |
| colors that are not displayable on the original mastering display. |
| |
| This extension adds the ability to pass the SMPTE 2086 metadata via EGL, |
| from which the color volume can be derived. While the general purpose of the |
| metadata is to assist in the transformation between different color volumes |
| of different displays and help achieve better color reproduction, it is not |
| in the scope of this extension to define how exactly the metadata should be |
| used in such a process. It is up to the implementation to determine how to |
| make use of the metadata. |
| |
| New Procedures and Functions |
| |
| None. |
| |
| New Tokens |
| |
| Accepted as attribute by eglSurfaceAttrib and eglQuerySurface: |
| |
| EGL_SMPTE2086_DISPLAY_PRIMARY_RX_EXT 0x3341 |
| EGL_SMPTE2086_DISPLAY_PRIMARY_RY_EXT 0x3342 |
| EGL_SMPTE2086_DISPLAY_PRIMARY_GX_EXT 0x3343 |
| EGL_SMPTE2086_DISPLAY_PRIMARY_GY_EXT 0x3344 |
| EGL_SMPTE2086_DISPLAY_PRIMARY_BX_EXT 0x3345 |
| EGL_SMPTE2086_DISPLAY_PRIMARY_BY_EXT 0x3346 |
| EGL_SMPTE2086_WHITE_POINT_X_EXT 0x3347 |
| EGL_SMPTE2086_WHITE_POINT_Y_EXT 0x3348 |
| EGL_SMPTE2086_MAX_LUMINANCE_EXT 0x3349 |
| EGL_SMPTE2086_MIN_LUMINANCE_EXT 0x334A |
| |
| Additions to Chapter "3.5.6 Surface Attributes" of the EGL 1.5 Specification |
| |
| Add the following paragraph before the "Errors" section on page 43, |
| |
| If attribute is EGL_SMPTE2086_DISPLAY_PRIMARY_RX_EXT, EGL_SMPTE2086_- |
| DISPLAY_PRIMARY_RY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_GX_EXT, EGL_- |
| SMPTE2086_DISPLAY_PRIMARY_GY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_BX_EXT |
| or EGL_SMPTE2086_DISPLAY_PRIMARY_BY_EXT, then value indicates the |
| corresponding xy chromaticity coordinate[12] of the mastering display's |
| red, green or blue color primary, as configured for the mastering |
| process. The floating-point display primary coordinates should be |
| multiplied by EGL_METADATA_SCALING_EXT (50000)[13], before being passed |
| into eglSurfaceAttrib as integers. |
| |
| If attribute is EGL_SMPTE2086_WHITE_POINT_X_EXT or EGL_SMPTE2086_WHITE_- |
| POINT_Y_EXT, then value indicates the corresponding xy chromaticity |
| coordinate[12] of the mastering display's white point, as configured for |
| the mastering process. The floating-point white point chromaticity |
| coordinates should be multiplied by EGL_METADATA_SCALING_EXT (50000), |
| before being passed into eglSurfaceAttrib as integers. |
| |
| If attribute is EGL_SMPTE2086_MAX_LUMINANCE_EXT or EGL_SMPTE2086_MIN_- |
| LUMINANCE_EXT, then value indicates the maximum or minimum display |
| luminance of the mastering display, as configured for the mastering |
| process. The unit of value is 1 nit (candela per square meter). The |
| floating-point luminance values should be multiplied by |
| EGL_METADATA_SCALING_EXT, a constant scaling factor of 50000, before |
| being passed into eglSurfaceAttrib as integers. |
| |
| By defining the mastering display's color volume through color |
| primaries, white point, and luminance range, applications give EGL |
| and the underlying display pipeline hints as to how to reproduce colors |
| more closely to the original content when created on the mastering |
| display. Exactly how the color volume information is used to assist the |
| color reproduction process is implementation dependant. |
| |
| The initial values of EGL_SMPTE2086_DISPLAY_PRIMARY_RX_EXT, EGL_- |
| SMPTE2086_DISPLAY_PRIMARY_RY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_GX_EXT, |
| EGL_SMPTE2086_DISPLAY_PRIMARY_GY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_BX_- |
| EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_BY_EXT, EGL_SMPTE2086_WHITE_POINT_X_- |
| EXT, EGL_SMPTE2086_WHITE_POINT_Y_EXT, EGL_SMPTE2086_MAX_LUMINANCE_EXT |
| and EGL_SMPTE2086_MIN_LUMINANCE_EXT are EGL_DONT_CARE, which causes the |
| hints to be ignored. If value is not in the implementation's supported |
| range for attribute, a EGL_BAD_PARAMETER error is generated, and some or |
| all of the metadata fields are ignored. |
| |
| Add the following footnote at the end of page 43, and increment all the |
| subsequent footnote numbers in Chapter 3, |
| |
| [12] Chromaticity coordinates x and y are as specified in CIE |
| 15:2004 "Calculation of chromaticity coordinates" (Section 7.3) and are |
| limited to between 0 and 1 for real colors for the mastering display. |
| |
| Change the original footnote 12 at the end of section "3.5.6 Surface |
| Attributes" on page 45 to, |
| |
| [13] EGL_DISPLAY_SCALING (10000) and EGL_METADATA_SCALING_EXT (50000) |
| are used where EGL needs to take or return floating-point attribute |
| values, which would normally be smaller than 1, as integers while still |
| retaining sufficient precision to be meaningful. |
| |
| Addition to Table 3.5 "Queryable surface attributes and types", |
| |
| Attribute Type |
| ------------------------------------------------ |
| EGL_SMPTE2086_DISPLAY_PRIMARY_RX_EXT integer |
| EGL_SMPTE2086_DISPLAY_PRIMARY_RY_EXT integer |
| EGL_SMPTE2086_DISPLAY_PRIMARY_GX_EXT integer |
| EGL_SMPTE2086_DISPLAY_PRIMARY_GY_EXT integer |
| EGL_SMPTE2086_DISPLAY_PRIMARY_BX_EXT integer |
| EGL_SMPTE2086_DISPLAY_PRIMARY_BY_EXT integer |
| EGL_SMPTE2086_WHITE_POINT_X_EXT integer |
| EGL_SMPTE2086_WHITE_POINT_Y_EXT integer |
| EGL_SMPTE2086_MAX_LUMINANCE_EXT integer |
| EGL_SMPTE2086_MIN_LUMINANCE_EXT integer |
| |
| Description |
| ------------------------------------------------------------------------------------------ |
| x chromaticity coordinate for red display primary multiplied by EGL_METADATA_SCALING_EXT |
| y chromaticity coordinate for red display primary multiplied by EGL_METADATA_SCALING_EXT |
| x chromaticity coordinate for green display primary multiplied by EGL_METADATA_SCALING_EXT |
| y chromaticity coordinate for green display primary multiplied by EGL_METADATA_SCALING_EXT |
| x chromaticity coordinate for blue display primary multiplied by EGL_METADATA_SCALING_EXT |
| y chromaticity coordinate for blue display primary multiplied by EGL_METADATA_SCALING_EXT |
| x chromaticity coordinate for white point multiplied by EGL_METADATA_SCALING_EXT |
| y chromaticity coordinate for white point multiplied by EGL_METADATA_SCALING_EXT |
| Maximum luminance in nit multiplied by EGL_METADATA_SCALING_EXT |
| Minimum luminance in nit multiplied by EGL_METADATA_SCALING_EXT |
| |
| Add the following paragraph at the end of section "3.5.6 Surface Attributes" |
| on page 45, |
| |
| Querying EGL_SMPTE2086_DISPLAY_PRIMARY_RX_EXT, EGL_SMPTE2086_DISPLAY_- |
| PRIMARY_RY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_GX_EXT, EGL_SMPTE2086_- |
| DISPLAY_PRIMARY_GY_EXT, EGL_SMPTE2086_DISPLAY_PRIMARY_BX_EXT or EGL_- |
| SMPTE2086_DISPLAY_PRIMARY_BY_EXT returns respectively the xy |
| chromaticity coordinate of the mastering display's red, green or blue |
| color primary, multiplied by the constant value EGL_METADATA_SCALING_EXT |
| (50000). The display primary coordinates can be set via eglSurfaceAttrib |
| as described above. |
| |
| Querying EGL_SMPTE2086_WHITE_POINT_X_EXT, or EGL_SMPTE2086_WHITE_POINT_- |
| Y_EXT returns respectively the xy chromaticity coordinate of the |
| mastering display's white point, multiplied by the constant value EGL_- |
| METADATA_SCALING (50000). The white point coordinates can be set via |
| eglSurfaceAttrib as described above. |
| |
| Querying EGL_SMPTE2086_MAX_LUMINANCE_EXT or EGL_SMPTE2086_MIN_- |
| LUMINANCE_EXT returns respectively the maximum and minimum display |
| luminance of the mastering display. The values returned are in units of |
| 1 nit (candela per square meter), multiplied by the constant value EGL_- |
| METADATA_SCALING (50000). The value of EGL_SMPTE2086_MAX_LUMINANCE_EXT |
| and EGL_SMPTE2086_MIN_LUMINANCE_EXT can be set via eglSurfaceAttrib as |
| described above. |
| |
| Errors |
| |
| Described in the body text above. |
| |
| Issues |
| |
| 1. Should this extension define a valid data range for each metadata field? |
| |
| RESOLVED: No. It is not in the scope of this extension to define how the |
| metadata hints should be used in the display pipeline and, as a result, |
| what the valid data ranges are for the metadata fields. It is |
| implementation dependant, but related standards, such as SMPTE ST 2086, |
| can be used as reference. As described in the body, implemetations may |
| generate a EGL_BAD_PARAMTER error to notify applications that the input |
| metadata values are invalid or not supported. |
| |
| Revision History |
| |
| Version 1, 2016/04/22 |
| - Initial draft |
| |
| Version 2, 2016/05/25 |
| - Rename to EXT and introduce a new scaling factor |
| |
| Version 3, 2016/10/19 |
| - Add an error and revise issue 1 |
| |
| Version 4, 2016/11/22 |
| - Change status to complete |
| |
| Version 5, 2016/11/29 |
| - Add token assigments |
| |
| Version 6, 2017/02/28 |
| - Add 'EXT' suffix to 'EGL_METADATA_SCALING' |
| |
| Version 7, 2017/10/13 |
| - Rename EGL_INVALID_VALUE (which doesn't exist) to EGL_FALSE |
| |
| Version 8, 2017/10/16 |
| - Fix v7 change to use EGL_BAD_PARAMETER as the error code |
| generated vs. EGL_FALSE which is the expected return value of |
| the function. |
| |
