Comment 32 for bug 1930982

The circumstantial evidence "seems like" something in the function here (https://searchfox.org/mozilla-central/source/gfx/wr/swgl/src/composite.h#534) is underflowing. But I would need someone who can reliably reproduce the issue to find out where in those math equations are actually doing so. I tried testing in my patch if the additions were the culprit, but that seems unlikely.

It's possible the multiplications "rbCoeffs * uv" or "gCoeffs * uv" are underflowing based on whatever values the ARM video codecs seem to be supplying. However, this is not happening on x86 at all, which is strange, and it is also happening on ARM across platform, which is further strange, since there isn't really much in the way of platform specific code here.

Sotaro, might you be able to investigate this?