No it's not. But, the previous code was already effectively doing "c * c" for the last 15 years. So for now, just keep doing that, a bit faster.
A more proper way would be to do proper color-space aware luma calculation. Which under default settings is sRGB indeed, but not necessarily so (VSE can be set to operate in some other color space). Someday!
A more proper way would be to do proper color-space aware luma calculation. Which under default settings is sRGB indeed, but not necessarily so (VSE can be set to operate in some other color space). Someday!