H264_nvenc harware encoding do not set quality properly

[kwiwtov]

Using h264_nvenc to save my project. If I set quality settings the result file is:

60% quality = 5.3mb
70% = 12mb
80% = 18 mb
90% = 18 mb (!)
100% = 3 mb (!!!)

So as you can see, after 80% quantizer stops work properly and do not increases bitrate and even significantly decreses it on 100%

Used settings:
1280 x 30fps 264 H.main profile

System: windows 10 x64 ver 1909
Shotcut 19.10.20

The same settings on CPU encoding works fine and linearly increases file size

[shotcut]

This is not a bug under our control. NVENC does not really support >70% very well. Ask NVIDIA

See also Export is Making Larger and Larger File Sizes [19.10.20 - Win 10]

[kwiwtov]

OK. Thank you for quick answer!