Scarfski/basis_universal
1
0
Fork 0
mirror of https://github.com/BinomialLLC/basis_universal.git synced 2026-06-08 08:33:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fix link for Candela per square meter in README

Browse Source 
Updated the link for the Candela per square meter reference in the README.
This commit is contained in:
Rich Geldreich
2026-01-24 21:09:29 -05:00
committed by GitHub
parent 00910a1c56
commit 6218d273ba
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
README.md
View File

@@ -305,7 +305,7 @@ Note the unified `-quality` and `-effort` options work in HDR, too. These exampl
Be aware that the .EXR reader we're using is [TinyEXR's](https://github.com/syoyo/tinyexr), which doesn't support all possible .EXR compression modes. Tools like [ImageMagick](https://imagemagick.org/) can be used to create .EXR files that TinyEXR can read.
Alternatively, LDR images (such as .PNG) can be compressed to an HDR format by specifying `-hdr`, `-hdr_6x6`, or `-hdr_6x6i`. By default LDR images, when compressed to an HDR format, are first upconverted to HDR by converting them from sRGB to linear light and scaled to 100 [nits](https://en.wikipedia.org/wiki/Candela_per_square_metre) (candelas per square meter). The sRGB conversion step can be disabled by specifying `-hdr_ldr_no_srgb_to_linear`, and the normalized RGB linear light to nit multiplier can be changed by specifying `-hdr_ldr_upconversion_nit_multiplier X`.
Alternatively, LDR images (such as .PNG) can be compressed to an HDR format by specifying `-hdr`, `-hdr_6x6`, or `-hdr_6x6i`. By default LDR images, when compressed to an HDR format, are first upconverted to HDR by converting them from sRGB to linear light and scaled to 100 [nits](https://grokipedia.com/page/Candela_per_square_metre) (candelas per square meter). The sRGB conversion step can be disabled by specifying `-hdr_ldr_no_srgb_to_linear`, and the normalized RGB linear light to nit multiplier can be changed by specifying `-hdr_ldr_upconversion_nit_multiplier X`.
Note: If you're compressing LDR/SDR image files to an HDR format, the codec's default behavior is to convert the 8-bit image data to linear light (by undoing the sRGB transfer function). It then multiplies the linear light RGB values by the LDR->HDR upconversion multiplier, which is in [nits (candela per sq. meter)](https://en.wikipedia.org/wiki/Candela_per_square_metre). In previous versions of the codec, this multiplier was effectively 1 nit, but it now defaults to 100 nits in all modes. (The typical luminance of LDR monitors is 80-100 nits.) To change this, use the "-hdr_ldr_upconversion_nit_multiplier X" command line option. (This is done because the HDR 6x6 codecs function internally in the [ICtCp HDR colorspace](https://en.wikipedia.org/wiki/ICtCp). LDR/SDR images must be upconverted to linear light HDR images scaled to a proper max. luminance based on how the image data will be displayed on actual SDR/HDR monitors.)