This is my first post on the forum and I registered specifically to ask this question because I've Googled phrases such as:
- handbrake nvenc_h265 compare encoder-preset values "hq" "hp" "fast" "medium" "slow" "default"
- handbrake nvenc_h265 "default" vs "slow"
- handbrake "nvenc" "default" vs "high quality"

... and based on the search results I'm getting, I clearly need a better way to articulate what I'm looking for!

The gist of it is I can't find an authoritative guide or documentation on the exact differences between these settings:

PS C:\Program Files\HandBrake> ./HandBrakeCLI --encoder-preset-list nvenc_h265

Available --encoder-preset values for 'nvenc_h265' encoder:
... and would love it if someone could explain them clearly to me. In particular I don't understand if "high quality" being at the top of the scale is significant and if my expectations should be that encodes with this will actually yield less quality than "default" or "medium". x265 is so much more clear-cut!

I have a decent grasp of the differences between CPU-based encoding (such as with x265) vs Nvidia's GPU encoder, in so much as I've done numerous encodes of my own and can definitely see the pros & cons.

But where this is all leading is I want to figure out the best possible outcome that I can get with NVEnc, and see at what tier that compares with my x265 encodes. For example should I expect (subjectively) a "slow nvenc" to be comparable to a "superfast x265"?

And then following on from that, see if there's a way to set the NVEnc & tune to get something equivalent to say "medium x265". That would be ideal. I'm accepting of the trade-off in quality & slightly higher bitrate, for the enormous speed increase (aren't we all), but I just want to see how comparable they can realistically be.
I should also mention that I'm using the GTX1050, so... Pascal, which may be important if your data/findings are for the newer chip sets having the B-frame inclusion.

Thank you all.