General question regarding GPU Acceleration

[Djinn]

I get that GPU acceleration for encoding is available for one-pass conversions, and it's disabled when you switch to higher-quality two-pass conversions.

Can someone explain to me why this is the case? Don't get me wrong; I have faith in DVDFab, and I trust there's a good reason - but I'm curious as to what it is. It would be incredible if I could get both the quality of two-pass conversions, and the speed of GPU acceleration.

[Wilson.Wang]

hi Djinn,

Soft X264 two pass is scan first, then use scaned data to improve encode quality.
Nvidia Nvenc two pass is a param, just encode once, but tell hardware use high quality params to improve encode. But should not expect quality like soft two pass.
We will modify this to avoid confuse. Just let nvenc hardware use two pass params if select two pass set.

Yours,
Wilson