From 380f72f1566a39dd92f1572b8c0aa68e6c799895 Mon Sep 17 00:00:00 2001 From: Patrick Hulce Date: Sat, 25 Jan 2025 20:17:12 -0600 Subject: [PATCH] docs: clarify exr2aces output format Inspired by discussion in https://github.com/AcademySoftwareFoundation/openexr/issues/1962. Adds additional background to the ACES Image Container format produced by exr2aces. Signed-off-by: Patrick Hulce --- website/bin/exr2aces.rst | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/website/bin/exr2aces.rst b/website/bin/exr2aces.rst index 622850e8f1..eab3009cee 100644 --- a/website/bin/exr2aces.rst +++ b/website/bin/exr2aces.rst @@ -15,8 +15,10 @@ Description Read an OpenEXR file from infile and save the contents in ACES image file outfile. -The ACES image file format is a subset of the OpenEXR file -format. ACES image files are restricted as follows: +The ACES image file format defined by `SMPTE ST 2065-4`_ +is a subset of the OpenEXR file format. + +ACES image container files generally follow these restrictions: - Images are stored as scanlines; tiles are not allowed. @@ -36,6 +38,12 @@ format. ACES image files are restricted as follows: - The "chromaticities" header attribute must specify the ACES RGB primaries and white point. +Note that perfect adherence to the specification is not strictly +necessary for many use cases and often diverges in minor ways +(e.g. the use of PIZ compression in exr2aces is technically off-spec), +but the file generated here is generally suitable for broadly +compatible archival. + Options: -------- @@ -52,3 +60,4 @@ Options: print version information +.. _SMPTE ST 2065-4: https://doi.org/10.5594/SMPTE.ST2065-4.2013