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This is the recommended filter.
Color Metadata NCLC/NCLX
The above gets the underlying data stored correctly, but there are additional metadata flags that can be set that are interpreted by some players, these are the NCLC color tags for color primaries, transfer function and conversion matrix. This is defined as a ISO spec here (see https://www.iso.org/standard/73412.html). The numbers below are part of the definition.
NCLC stands for Non-Consistent Luminance Coding, a brief overview of its history is here. For MP4 files, its also known as NCLX. Additionally this metadata can also be represented in the h264 metadata stream in the video usability Information (VUI) block.
You can read the metadata using mp4box.js which is a visual browser of the mp4 metadata, and look at moov/trak/mdia/minf/stbl/stsd/avc1/colr
NOTE: None of the flags below affect the encoding of the source imagery, they are meant to be used to guide how the mp4 file is decoded.
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