Dolby Digital (5.1 to 7.1) upmixing is incorrect

[Hydra-Spectre]

I have noticed many issues with the Dolby Digital (5.1 to 7.1 augmented) upmixing config.

The general upmixing is just incorrect. The front channels aren't supposed to spread into the side surrounds. The upmixing should fully transfer the rears over to the side surrounds while doing a mono duplicate of them to the rears with some matrix decoding from Dolby Digital EX/DTS-ES.

I figured this is supposedly based on Dolby Pro Logic IIx upmixing 5.1 to 6.1, but it doesn't work well, which is a shame. I would love a corrected version to decode my 6.1 matrixed movies to proper 6.1.